CA2111808C - Method for forming a bragg grating in an optical medium - Google Patents
Method for forming a bragg grating in an optical mediumInfo
- Publication number
- CA2111808C CA2111808C CA002111808A CA2111808A CA2111808C CA 2111808 C CA2111808 C CA 2111808C CA 002111808 A CA002111808 A CA 002111808A CA 2111808 A CA2111808 A CA 2111808A CA 2111808 C CA2111808 C CA 2111808C
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- Prior art keywords
- grating
- optical fiber
- actinic radiation
- optical
- phase grating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Links
- 238000000034 method Methods 0.000 title claims abstract description 43
- 230000003287 optical effect Effects 0.000 title claims abstract description 29
- 239000013307 optical fiber Substances 0.000 claims abstract description 51
- 239000011521 glass Substances 0.000 claims abstract description 12
- 230000005855 radiation Effects 0.000 claims description 34
- 238000005253 cladding Methods 0.000 claims description 8
- 230000003595 spectral effect Effects 0.000 claims description 8
- 230000005670 electromagnetic radiation Effects 0.000 claims description 7
- 238000002310 reflectometry Methods 0.000 claims description 7
- 230000000638 stimulation Effects 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 7
- 230000015572 biosynthetic process Effects 0.000 abstract description 3
- 239000000835 fiber Substances 0.000 description 44
- 230000000737 periodic effect Effects 0.000 description 7
- 238000005286 illumination Methods 0.000 description 6
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 238000000609 electron-beam lithography Methods 0.000 description 2
- 230000002452 interceptive effect Effects 0.000 description 2
- 238000000411 transmission spectrum Methods 0.000 description 2
- 241000046695 Mitra lens Species 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000005350 fused silica glass Substances 0.000 description 1
- 238000001093 holography Methods 0.000 description 1
- 238000000059 patterning Methods 0.000 description 1
- 239000006089 photosensitive glass Substances 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02057—Optical fibres with cladding with or without a coating comprising gratings
- G02B6/02076—Refractive index modulation gratings, e.g. Bragg gratings
- G02B6/02123—Refractive index modulation gratings, e.g. Bragg gratings characterised by the method of manufacture of the grating
- G02B6/02133—Refractive index modulation gratings, e.g. Bragg gratings characterised by the method of manufacture of the grating using beam interference
- G02B6/02138—Refractive index modulation gratings, e.g. Bragg gratings characterised by the method of manufacture of the grating using beam interference based on illuminating a phase mask
Abstract
The invention involves a method for making Bragg gratings in glass optical fibers, or other glass optical waveguides (10), which is relatively insensitive to perturbations in the actinic light used for processing. This method is suitable for mass production and lends itself well to the manufacturing environment. The inventive method involves first providing an optical phase grating (20). An interference pattern is generated by impinging a single light beam (30) on the grating. The optical waveguide to be processed is exposed to this interference pattern, leading to the formation of a Bragg grating in the waveguide.
Description
2~~~gpg METHOD FOR FORMING A BRAGG GRATING IN AN OPTICAL MEDIUM
Field of the Invention This invention relates to methods of processing optical media in order to form gratings within them, and more particularly, to methods for forming Bragg gratings in photosensitive optical fibers.
Art Background Certain prior-art methods for making Bragg gratings in optical fibers involve side-illumination of the fiber by a pair of interfering, actinic light beams.
Although they are capable of producing gratings of high quality, these methods are disadvantageous because they are difficult to implement in a manufacturing environment. That is, each of these prior art methods requires interferometric systems having high mechanical stability, and/or demands rigorous control of the spatiotemporal properties of the actinic beams.
Summary of the Invention We have discovered a method for making Bragg gratings in glass optical fibers, or other glass optical waveguides, which is relatively insensitive to perturbations in the actinic light used for processing. This method is suitable for mass production and lends itself well to the manufacturing environment.
The inventive method involves first providing an optical phase grating.
An interference pattern is generated by impinging a single light beam on the grating.
The optical waveguide to be processed is exposed to this interference pattern, leading to the formation of a Bragg grating in the waveguide.
In accordance with one aspect of the present invention there is provided a method for forming a grating in an optical fiber having a core and a cladding, and comprising a glass that is sensitive to at least some wavelengths of electromagnetic radiation, to be referred to as "actinic radiation," the method comprising the steps of: a) providing an optical phase grating having an average period to be denoted P 1;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern; and c) exposing at least a first optical fiber to the interference pattern such that a grating pattern of refractive index »c'~. . , .._...._.........~........_..........--....._............. ._ .....
....,_.._~..m.".~.~...-----....... ..,.._,..m.~....~.,_....~.-....... . ....
- la -modulations is formed in at least the core of the optical fiber, the optical fiber grating pattern having an average period to be denoted P2; wherein d) during the exposing step, the optical fiber is exposed to actinic radiation from two non-adjacent, diffractive orders, resulting in a value for P2 that is approximately ( 1 /n) x P 1, wherein n is an integer greater than 1.
In accordance with another aspect of the present invention there is provided a method for processing an optical fiber having a core and a cladding, and comprising a glass that is sensitive to at least some wavelengths of electromagnetic radiation, to be referred to as "actinic radiation," the method comprising forming a first grating in the optical fiber and forming at least a second grating in the optical fiber, wherein each respective grating-forming step comprises: a) providing an optical phase grating; b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern; and c) exposing the optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, wherein: d) the exposing steps are carried out such that the respective first and second gratings are formed in spatially separated portions of the optical fiber, and such that an optical cavity is defined within the optical fiber between the first and second gratings.
Brief Description of the Drawings FIG. 1 schematically depicts an illumination geometry for processing an optical fiber according to the invention.
FIG. 2 schematically depicts the illumination geometry of FIG. l, with fiu they details.
FIG. 3 is the transmission spectrum of a fiber grating made according to the invention, in one embodiment.
Detailed Description An optical phase grating imposes a periodic, or nearly periodic, phase modulation on the incident, actinic beam. As a result, impingement on the grating of a single beam may result in the generation of two or more beams of diffracted radiation. The phase grating of the inventive method, to he referred to as a "phase mask," can be made by any of numerous methods well-known in those arts that 2~1~.8~8 relate to diffraction gratings and holography. These methods include both lithographic and holographic techniques.
The period of the phase mask will generally be the same as the period of the desired Bragg grating in the fiber or other waveguide to be processed.
(The optical waveguiding medium to be processed will hereafter be referred to as an optical fiber. This is for convenience, and is not intended to limit the scope of the invention.) However, a fiber Bragg grating having a period that is a sub-multiple of the phase-mask period is readily made by exposing the fiber to radiation in non-adjacent diffractive orders of the phase mask. Thus, the mask period may, in fact, be twice the period of the fiber Bragg grating, or some other integer multiple of that period. In at least some cases, the manufacture of phase masks will be simplified if the phase-mask period is greater than the fiber-grating period.
The period of the grating formed in the fiber (or other waveguide) by the inventive method will be largely independent of the wavelength of the actinic radiation (for a given phase mask). As a result, the requirement for temporal coherence of the source of actinic radiation is substantially relaxed relative to prior art methods. Moreover, this independence makes it possible to fully determine the period of a resulting fiber grating by specifying only the mask properties, irrespective of the source of actinic radiation. This relaxes constraints on the spectral stability of the radiation source, and allows flexibility in the selection of the radiation source. In particular, a phase mask that has been created by the interfering beams from a given radiation source can then be used to process an optical fiber by illuminating it with radiation from an entirely different source.
With reference to FIG. 1, fiber 10 (which is to be processed) is situated near phase mask 20. The portion of fiber 10 that is to be processed is preferably situated some distance away from the phase mask, in order to establish, on the fiber, the required interference pattern. A typical separation between the center of the fiber core and the surface of the phase mask is 0.5 mm. (It should be noted that the core of a typical communication optical fiber will generally be situated far enough from the phase mask even when the cladding is touching the phase mask.) In the figure, the axis perpendicular to the phase mask is denoted the z-axis, the axis parallel to the grating lines of the phase mask is denoted the x-axis, and the axis perpendicular to the x- and z-axes is denoted the y-axis. Light beam 30, which is incident on the phase mask, makes an incidence angle 8 with the z axis.
The longitudinal axis of fiber 10 is oriented at a rotational angle a relative to the y axis, and at a tilt angle 90 ° - (3 relative to the z-axis. According to a currently 21~~f~08 preferred method, the angles a and (3 are both zero. When the fiber is processed using light from adjacent diffractive orders, the angle 8 will generally not be zero.
However, normal incidence (8 = 0) may be appropriate when non-adj acent orders are used.
An appropriate phase mask may be, for example) a transmission surface grating, a reflection surface grating, or even a volume hologram. For example, we have made a transmission phase mask, about 0.5 cm long, by patterning a thin chromium layer deposited on the surface of a fused silica plate. The chromium layer was patterned by electron beam lithography to form an amplitude mask having a period of 520 nm, with lines and spaces approximately equally wide. The silica plate was subjected to reactive ion etching through the amplitude mask, forming corrugations about 250 nm deep, and the patterned chromium layer was then removed.
The corrugations are depicted schematically as feature 40 of FIG. 2.
'The purpose of these corrugations is to vary the phase of incident light in a spatially periodic or nearly periodic manner. Moreover, the energy distribution into the various diffractive orders of the phase mask depends on the design of the corrugations, as is well known in the art of grating-diffraction theory.
The mask was illuminated with light at a wavelength of 242 nm from a pulsed laser source 50. The light in the resulting diffraction pattern was distributed in an approximate 2:1 ratio between the zeroeth-order and first-order diffracted beams, respectively. There was also significant light emitted in other orders.
A
commercially available AT&T ACCUTETHERTnt optical fiber was aligned parallel to the phase mask and approximately perpendicular to the lines of the phase mask.
The distance between the fiber and the phase mask was about 0.5 mm.
The beam was focused onto the fiber by a cylindrical lens 55 having a focal length of 1 m. Lens 55 was situated between source 50 and phase mask 20.
It should be noted that by using a suitable magnifying or reducing projection system 57 situated between phase mask 20 and fiber 10, it is possible to form a fiber grating having a period that is different from the period of the phase mask. In fact, by using a zoom system (i.e., a projective optical system having variable reduction and/or variable magnification), it is possible to continuously vary the period of the resulting fiber grating. This is advantageous, for example, when it is simpler to manufacture phase masks having a larger period than the resulting gratings.
21~.~~Q~
Field of the Invention This invention relates to methods of processing optical media in order to form gratings within them, and more particularly, to methods for forming Bragg gratings in photosensitive optical fibers.
Art Background Certain prior-art methods for making Bragg gratings in optical fibers involve side-illumination of the fiber by a pair of interfering, actinic light beams.
Although they are capable of producing gratings of high quality, these methods are disadvantageous because they are difficult to implement in a manufacturing environment. That is, each of these prior art methods requires interferometric systems having high mechanical stability, and/or demands rigorous control of the spatiotemporal properties of the actinic beams.
Summary of the Invention We have discovered a method for making Bragg gratings in glass optical fibers, or other glass optical waveguides, which is relatively insensitive to perturbations in the actinic light used for processing. This method is suitable for mass production and lends itself well to the manufacturing environment.
The inventive method involves first providing an optical phase grating.
An interference pattern is generated by impinging a single light beam on the grating.
The optical waveguide to be processed is exposed to this interference pattern, leading to the formation of a Bragg grating in the waveguide.
In accordance with one aspect of the present invention there is provided a method for forming a grating in an optical fiber having a core and a cladding, and comprising a glass that is sensitive to at least some wavelengths of electromagnetic radiation, to be referred to as "actinic radiation," the method comprising the steps of: a) providing an optical phase grating having an average period to be denoted P 1;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern; and c) exposing at least a first optical fiber to the interference pattern such that a grating pattern of refractive index »c'~. . , .._...._.........~........_..........--....._............. ._ .....
....,_.._~..m.".~.~...-----....... ..,.._,..m.~....~.,_....~.-....... . ....
- la -modulations is formed in at least the core of the optical fiber, the optical fiber grating pattern having an average period to be denoted P2; wherein d) during the exposing step, the optical fiber is exposed to actinic radiation from two non-adjacent, diffractive orders, resulting in a value for P2 that is approximately ( 1 /n) x P 1, wherein n is an integer greater than 1.
In accordance with another aspect of the present invention there is provided a method for processing an optical fiber having a core and a cladding, and comprising a glass that is sensitive to at least some wavelengths of electromagnetic radiation, to be referred to as "actinic radiation," the method comprising forming a first grating in the optical fiber and forming at least a second grating in the optical fiber, wherein each respective grating-forming step comprises: a) providing an optical phase grating; b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern; and c) exposing the optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, wherein: d) the exposing steps are carried out such that the respective first and second gratings are formed in spatially separated portions of the optical fiber, and such that an optical cavity is defined within the optical fiber between the first and second gratings.
Brief Description of the Drawings FIG. 1 schematically depicts an illumination geometry for processing an optical fiber according to the invention.
FIG. 2 schematically depicts the illumination geometry of FIG. l, with fiu they details.
FIG. 3 is the transmission spectrum of a fiber grating made according to the invention, in one embodiment.
Detailed Description An optical phase grating imposes a periodic, or nearly periodic, phase modulation on the incident, actinic beam. As a result, impingement on the grating of a single beam may result in the generation of two or more beams of diffracted radiation. The phase grating of the inventive method, to he referred to as a "phase mask," can be made by any of numerous methods well-known in those arts that 2~1~.8~8 relate to diffraction gratings and holography. These methods include both lithographic and holographic techniques.
The period of the phase mask will generally be the same as the period of the desired Bragg grating in the fiber or other waveguide to be processed.
(The optical waveguiding medium to be processed will hereafter be referred to as an optical fiber. This is for convenience, and is not intended to limit the scope of the invention.) However, a fiber Bragg grating having a period that is a sub-multiple of the phase-mask period is readily made by exposing the fiber to radiation in non-adjacent diffractive orders of the phase mask. Thus, the mask period may, in fact, be twice the period of the fiber Bragg grating, or some other integer multiple of that period. In at least some cases, the manufacture of phase masks will be simplified if the phase-mask period is greater than the fiber-grating period.
The period of the grating formed in the fiber (or other waveguide) by the inventive method will be largely independent of the wavelength of the actinic radiation (for a given phase mask). As a result, the requirement for temporal coherence of the source of actinic radiation is substantially relaxed relative to prior art methods. Moreover, this independence makes it possible to fully determine the period of a resulting fiber grating by specifying only the mask properties, irrespective of the source of actinic radiation. This relaxes constraints on the spectral stability of the radiation source, and allows flexibility in the selection of the radiation source. In particular, a phase mask that has been created by the interfering beams from a given radiation source can then be used to process an optical fiber by illuminating it with radiation from an entirely different source.
With reference to FIG. 1, fiber 10 (which is to be processed) is situated near phase mask 20. The portion of fiber 10 that is to be processed is preferably situated some distance away from the phase mask, in order to establish, on the fiber, the required interference pattern. A typical separation between the center of the fiber core and the surface of the phase mask is 0.5 mm. (It should be noted that the core of a typical communication optical fiber will generally be situated far enough from the phase mask even when the cladding is touching the phase mask.) In the figure, the axis perpendicular to the phase mask is denoted the z-axis, the axis parallel to the grating lines of the phase mask is denoted the x-axis, and the axis perpendicular to the x- and z-axes is denoted the y-axis. Light beam 30, which is incident on the phase mask, makes an incidence angle 8 with the z axis.
The longitudinal axis of fiber 10 is oriented at a rotational angle a relative to the y axis, and at a tilt angle 90 ° - (3 relative to the z-axis. According to a currently 21~~f~08 preferred method, the angles a and (3 are both zero. When the fiber is processed using light from adjacent diffractive orders, the angle 8 will generally not be zero.
However, normal incidence (8 = 0) may be appropriate when non-adj acent orders are used.
An appropriate phase mask may be, for example) a transmission surface grating, a reflection surface grating, or even a volume hologram. For example, we have made a transmission phase mask, about 0.5 cm long, by patterning a thin chromium layer deposited on the surface of a fused silica plate. The chromium layer was patterned by electron beam lithography to form an amplitude mask having a period of 520 nm, with lines and spaces approximately equally wide. The silica plate was subjected to reactive ion etching through the amplitude mask, forming corrugations about 250 nm deep, and the patterned chromium layer was then removed.
The corrugations are depicted schematically as feature 40 of FIG. 2.
'The purpose of these corrugations is to vary the phase of incident light in a spatially periodic or nearly periodic manner. Moreover, the energy distribution into the various diffractive orders of the phase mask depends on the design of the corrugations, as is well known in the art of grating-diffraction theory.
The mask was illuminated with light at a wavelength of 242 nm from a pulsed laser source 50. The light in the resulting diffraction pattern was distributed in an approximate 2:1 ratio between the zeroeth-order and first-order diffracted beams, respectively. There was also significant light emitted in other orders.
A
commercially available AT&T ACCUTETHERTnt optical fiber was aligned parallel to the phase mask and approximately perpendicular to the lines of the phase mask.
The distance between the fiber and the phase mask was about 0.5 mm.
The beam was focused onto the fiber by a cylindrical lens 55 having a focal length of 1 m. Lens 55 was situated between source 50 and phase mask 20.
It should be noted that by using a suitable magnifying or reducing projection system 57 situated between phase mask 20 and fiber 10, it is possible to form a fiber grating having a period that is different from the period of the phase mask. In fact, by using a zoom system (i.e., a projective optical system having variable reduction and/or variable magnification), it is possible to continuously vary the period of the resulting fiber grating. This is advantageous, for example, when it is simpler to manufacture phase masks having a larger period than the resulting gratings.
21~.~~Q~
The fiber received an energy dose of about 1.7 mJ per pulse at 30 pulses per second. The total exposure time was about 20 minutes.
The transmission spectrum of the resulting grating 60 is shown in FIG. 3. As is evident in the figure, the grating had a main reflectivity peak centered at 1508.4 nm with a FWHM of 0.54 nm. Significantly, the peak reflectivity was greater than 90%. Such high reflectivities are important for making fiber lasers.
Clearly, peak reflectivities of 40% and more are readily attainable by this technique.
We believe that the inventive technique is readily applied not only to glass optical fibers, but also to other waveguiding geometries of photosensitive glass.
These include, for example, planar waveguides and channel waveguides. We intend the scope of the invention to include alternative waveguiding geometries such as these.
The inventive method is readily applied to produce multiple fiber gratings from a single phase mask. In one aspect, this is achieved by the sequential processing of a group of optical fibers. In a second aspect, this is achieved by the simultaneous processing of a group of optical fibers by exposing them to the interference pattern generated by a single phase mask.
In yet a third aspect, the multiple gratings are made in spatially separated regions of a single optical fiber. One way to achieve this is to provide a single phase mask that includes two or more spatially separated phase gratings, each corresponding to one of the respective fiber regions. These phase gratings may be illuminated either simultaneously or sequentially. Sequential illumination may be, e.g., by a continuous scan, or by separate exposure steps. Illumination may be by a single actinic beam, by multiple actinic beams that have been split from a single source, or by actinic beams from multiple sources.
A second way to achieve this is to provide a single phase mask that includes one phase grating long enough to generate appropriate interference patterns in all of the fespective fiber regions. Each of the respective fiber regions then corresponds to a particular section of the long phase grating. These corresponding sections ale, e.g., illuminated sequentially. If the long phase grating has a spatially varying period, it is readily used to form a group of two or more fiber gratings having different periods. Such a grating is also readily used to make a chirped fiber grating; i.e., a grating having a spatially varying period. For this purpose, illumination in a continuous scan of the phase mask will often be desirable.
~1~18J8 Formation of two or more spatially separated gratings in a single fiber is useful, e.g., for making optical cavities in fibers. If a suitable gain medium, such as a rare-earth-doped core, is included in the optical cavity, a fiber laser (or other waveguide laser, for a waveguide that is not an optical fiber) can be made in this fashion.
The inventive method offers control over several significant aspects of the fiber grating that is to be formed. For example, the amplitude of the refractive-index modulations in the fiber grating can itself be spatially modulated. With reference to FIG. 1, this is achieved, e.g., by an exposure step during which phase mask 20 is scanned, in the direction parallel to fiber 10, by actinic beam 30.
During the scan, the intensity of beam 30 is varied in a predetermined manner.
Moreover, the fiber grating can be blazed; that is, the phase fronts of actinic radiation within the fiber can be tilted in such a way that the resulting grating will couple light into or out of the fiber with enhanced efficiency. Blazing is achieved by rotating the phase mask relative to the fiber through an appropriate angle a, as shown in FIG. 1.
Furthermore, the profile of the phase mask can be generated by computer, and implemented, under computer control, by a method such as electron-beam lithography. This makes it possible to achieve numerous special effects.
For example, an appropriate phase mask having curved lines can be used to form a fiber grating that is capable of focusing light that is coupled into or out of the fiber.
The properties of the fiber grating are also affected by varying the angles 8 and Vii. (See FIG. 1.) By varying 8, some control is exerted over the diffraction efficiency into the various orders of the phase mask. Variations of 8 also affect the tilt angle of the grating formed within the optical fiber.
Varying (3 does not affect the diffraction efficiencies, but it offers some control over the period of the fiber grating. That is because the projection of the fiber grating onto the phase mask must have a period that is independent of ~3. Thus, a small change of (3 from zero will increase the period of the fiber grating by a factor of sec Vii. Changing (3 will also change the blaze of the fiber grating.
As noted, the relative amounts of light diffracted into the various orders of the phase mask can be changed somewhat by changing the incidence angle 8.
As is well-known in the relevant arts, the relative efficiencies of the diffractive orders can also be controlled by appropriate design of the phase mask. For example, normal incidence on a phase mask having a square grating profile of the appropriate amplitude will result in suppression of all even orders, with equal intensities 2111~~8 refracted into the +1 and -1 orders.
In the preceding discussion, it has been assumed that the phase mask is a phase grating; i.e., an optical element that imposes a periodic, or nearly periodic, phase modulation on the incident, actinic beam. However, it should be noted that in some cases it may be useful to provide an optical element that imposes, instead, a non-periodic phase modulation. Such a phase modulation will generate a complex wavefront when the optical element is illuminated with a single beam of actinic radiation. This complex wavefront may be useful for producing optical elements that include refractive index modulations more complex than Bragg gratings.
The transmission spectrum of the resulting grating 60 is shown in FIG. 3. As is evident in the figure, the grating had a main reflectivity peak centered at 1508.4 nm with a FWHM of 0.54 nm. Significantly, the peak reflectivity was greater than 90%. Such high reflectivities are important for making fiber lasers.
Clearly, peak reflectivities of 40% and more are readily attainable by this technique.
We believe that the inventive technique is readily applied not only to glass optical fibers, but also to other waveguiding geometries of photosensitive glass.
These include, for example, planar waveguides and channel waveguides. We intend the scope of the invention to include alternative waveguiding geometries such as these.
The inventive method is readily applied to produce multiple fiber gratings from a single phase mask. In one aspect, this is achieved by the sequential processing of a group of optical fibers. In a second aspect, this is achieved by the simultaneous processing of a group of optical fibers by exposing them to the interference pattern generated by a single phase mask.
In yet a third aspect, the multiple gratings are made in spatially separated regions of a single optical fiber. One way to achieve this is to provide a single phase mask that includes two or more spatially separated phase gratings, each corresponding to one of the respective fiber regions. These phase gratings may be illuminated either simultaneously or sequentially. Sequential illumination may be, e.g., by a continuous scan, or by separate exposure steps. Illumination may be by a single actinic beam, by multiple actinic beams that have been split from a single source, or by actinic beams from multiple sources.
A second way to achieve this is to provide a single phase mask that includes one phase grating long enough to generate appropriate interference patterns in all of the fespective fiber regions. Each of the respective fiber regions then corresponds to a particular section of the long phase grating. These corresponding sections ale, e.g., illuminated sequentially. If the long phase grating has a spatially varying period, it is readily used to form a group of two or more fiber gratings having different periods. Such a grating is also readily used to make a chirped fiber grating; i.e., a grating having a spatially varying period. For this purpose, illumination in a continuous scan of the phase mask will often be desirable.
~1~18J8 Formation of two or more spatially separated gratings in a single fiber is useful, e.g., for making optical cavities in fibers. If a suitable gain medium, such as a rare-earth-doped core, is included in the optical cavity, a fiber laser (or other waveguide laser, for a waveguide that is not an optical fiber) can be made in this fashion.
The inventive method offers control over several significant aspects of the fiber grating that is to be formed. For example, the amplitude of the refractive-index modulations in the fiber grating can itself be spatially modulated. With reference to FIG. 1, this is achieved, e.g., by an exposure step during which phase mask 20 is scanned, in the direction parallel to fiber 10, by actinic beam 30.
During the scan, the intensity of beam 30 is varied in a predetermined manner.
Moreover, the fiber grating can be blazed; that is, the phase fronts of actinic radiation within the fiber can be tilted in such a way that the resulting grating will couple light into or out of the fiber with enhanced efficiency. Blazing is achieved by rotating the phase mask relative to the fiber through an appropriate angle a, as shown in FIG. 1.
Furthermore, the profile of the phase mask can be generated by computer, and implemented, under computer control, by a method such as electron-beam lithography. This makes it possible to achieve numerous special effects.
For example, an appropriate phase mask having curved lines can be used to form a fiber grating that is capable of focusing light that is coupled into or out of the fiber.
The properties of the fiber grating are also affected by varying the angles 8 and Vii. (See FIG. 1.) By varying 8, some control is exerted over the diffraction efficiency into the various orders of the phase mask. Variations of 8 also affect the tilt angle of the grating formed within the optical fiber.
Varying (3 does not affect the diffraction efficiencies, but it offers some control over the period of the fiber grating. That is because the projection of the fiber grating onto the phase mask must have a period that is independent of ~3. Thus, a small change of (3 from zero will increase the period of the fiber grating by a factor of sec Vii. Changing (3 will also change the blaze of the fiber grating.
As noted, the relative amounts of light diffracted into the various orders of the phase mask can be changed somewhat by changing the incidence angle 8.
As is well-known in the relevant arts, the relative efficiencies of the diffractive orders can also be controlled by appropriate design of the phase mask. For example, normal incidence on a phase mask having a square grating profile of the appropriate amplitude will result in suppression of all even orders, with equal intensities 2111~~8 refracted into the +1 and -1 orders.
In the preceding discussion, it has been assumed that the phase mask is a phase grating; i.e., an optical element that imposes a periodic, or nearly periodic, phase modulation on the incident, actinic beam. However, it should be noted that in some cases it may be useful to provide an optical element that imposes, instead, a non-periodic phase modulation. Such a phase modulation will generate a complex wavefront when the optical element is illuminated with a single beam of actinic radiation. This complex wavefront may be useful for producing optical elements that include refractive index modulations more complex than Bragg gratings.
Claims (8)
1. A method for forming a grating in an optical fiber having a core and a cladding, and comprising a glass that is sensitive to at least some wavelengths of electromagnetic radiation, to be referred to as "actinic radiation," the method comprising the steps of:
a) providing an optical phase grating having an average period to be denoted P1;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern;
and c) exposing at least a first optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, the optical fiber grating pattern having an average period to be denoted P2; wherein d) during the exposing step, the optical fiber is exposed to actinic radiation from two non-adjacent, diffractive orders, resulting in a value for P2 that is approximately (1/n) x P1, wherein n is an integer greater than 1.
a) providing an optical phase grating having an average period to be denoted P1;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern;
and c) exposing at least a first optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, the optical fiber grating pattern having an average period to be denoted P2; wherein d) during the exposing step, the optical fiber is exposed to actinic radiation from two non-adjacent, diffractive orders, resulting in a value for P2 that is approximately (1/n) x P1, wherein n is an integer greater than 1.
2. The method of claim 1, wherein n = 2.
3. A method for forming a grating in an optical fiber having a core and a cladding, and comprising a glass that is sensitive to at least some wavelengths of electromagnetic radiation, to be referred to as "actinic radiation," the method comprising the steps of:
a) providing an optical phase grating;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern;
and c) exposing at least a first optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, wherein the impinging step comprises:
d) scanning the actinic beam along the phase grating, and during the scanning step, varying the intensity of the actinic beam.
a) providing an optical phase grating;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern;
and c) exposing at least a first optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, wherein the impinging step comprises:
d) scanning the actinic beam along the phase grating, and during the scanning step, varying the intensity of the actinic beam.
4. A method for forming a grating in an optical fiber having a core and a cladding, and comprising a glass that is sensitive to at least some wavelengths of electromagnetic radiation, to be referred to as "actinic radiation," the method comprising the steps of:
a) providing an optical phase grating;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern;
and c) exposing at least a first optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, wherein:
d) the phase grating has a spatially varying period, and the impinging step is conducted such that the resulting optical fiber grating pattern has a spatially varying period.
a) providing an optical phase grating;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern;
and c) exposing at least a first optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, wherein:
d) the phase grating has a spatially varying period, and the impinging step is conducted such that the resulting optical fiber grating pattern has a spatially varying period.
5. A method for forming a grating in an optical fiber having a core and a cladding, and comprising a glass that is sensitive to at least some wavelengths of electromagnetic radiation, to be referred to as "actinic radiation," the method comprising the steps of:
a) providing an optical phase grating;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern;
and c) exposing at least a first optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, wherein:
d) a peak reflectivity is associated with the optical fiber grating pattern with respect to at least one peak wavelength, and the exposing step is carried out such that the resulting peak reflectivity is at least 40%.
a) providing an optical phase grating;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern;
and c) exposing at least a first optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, wherein:
d) a peak reflectivity is associated with the optical fiber grating pattern with respect to at least one peak wavelength, and the exposing step is carried out such that the resulting peak reflectivity is at least 40%.
6. The method of claim 5, wherein the exposing step is carried out such that the resulting peak reflectivity is at least 90%.
7. A method for processing an optical fiber having a core and a cladding, and comprising a glass that is sensitive to at least some wavelengths of electromagnetic radiation, to be referred to as "actinic radiation," the method comprising forming a first grating in the optical fiber and forming at least a second grating in the optical fiber, wherein each respective grating-forming step comprises:
a) providing an optical phase grating;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern;
and c) exposing the optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, wherein:
d) the exposing steps are carried out such that the respective first and second gratings are formed in spatially separated portions of the optical fiber, and such that an optical cavity is defined within the optical fiber between the first and second gratings.
a) providing an optical phase grating;
b) impinging a single beam of actinic radiation on the phase grating such that actinic radiation of the same spectral content is diffracted into at least two diffractive orders of the phase grating, resulting in an interference pattern;
and c) exposing the optical fiber to the interference pattern such that a grating pattern of refractive index modulations is formed in at least the core of the optical fiber, wherein:
d) the exposing steps are carried out such that the respective first and second gratings are formed in spatially separated portions of the optical fiber, and such that an optical cavity is defined within the optical fiber between the first and second gratings.
8. The method of claim 7, wherein the optical fiber further comprises a laser gain medium, the exposing steps are carried out such that at least a portion of the gain medium is included within the optical cavity, and the exposing steps are further carried out such that appropriate stimulation will cause the resulting optical cavity to function as a laser.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US004,770 | 1993-01-14 | ||
US08/004,770 US5327515A (en) | 1993-01-14 | 1993-01-14 | Method for forming a Bragg grating in an optical medium |
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CA2111808A1 CA2111808A1 (en) | 1994-07-15 |
CA2111808C true CA2111808C (en) | 1999-11-23 |
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CA002111808A Expired - Fee Related CA2111808C (en) | 1993-01-14 | 1993-12-17 | Method for forming a bragg grating in an optical medium |
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US (1) | US5327515A (en) |
EP (1) | EP0606726B1 (en) |
JP (1) | JP3243102B2 (en) |
CA (1) | CA2111808C (en) |
DE (1) | DE69325640T2 (en) |
Families Citing this family (111)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5104209A (en) | 1991-02-19 | 1992-04-14 | Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of Communications | Method of creating an index grating in an optical fiber and a mode converter using the index grating |
US5367588A (en) * | 1992-10-29 | 1994-11-22 | Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of Communications | Method of fabricating Bragg gratings using a silica glass phase grating mask and mask used by same |
US5478371A (en) * | 1992-05-05 | 1995-12-26 | At&T Corp. | Method for producing photoinduced bragg gratings by irradiating a hydrogenated glass body in a heated state |
US5475780A (en) * | 1993-06-17 | 1995-12-12 | At&T Corp. | Optical waveguiding component comprising a band-pass filter |
EP0635736A1 (en) * | 1993-07-19 | 1995-01-25 | AT&T Corp. | Method for forming, in optical media, refractive index perturbations having reduced birefringence |
US5563732A (en) * | 1994-01-06 | 1996-10-08 | At&T Corp. | Laser pumping of erbium amplifier |
AUPM386794A0 (en) * | 1994-02-14 | 1994-03-10 | University Of Sydney, The | Optical grating |
GB2289771B (en) * | 1994-05-26 | 1997-07-30 | Northern Telecom Ltd | Forming Bragg gratings in photosensitive waveguides |
DE4432410B4 (en) * | 1994-08-31 | 2007-06-21 | ADC Telecommunications, Inc., Eden Prairie | Optoelectronic multi-wavelength device |
FR2728356B1 (en) * | 1994-12-15 | 1997-01-31 | Alcatel Fibres Optiques | DEVICE FOR PRINTING A BRAGG NETWORK IN AN OPTICAL FIBER |
US5604829A (en) * | 1995-04-17 | 1997-02-18 | Hughes Aircraft Company | Optical waveguide with diffraction grating and method of forming the same |
GB9509932D0 (en) * | 1995-05-17 | 1995-07-12 | Northern Telecom Ltd | Bragg gratings in waveguides |
WO1996036892A1 (en) * | 1995-05-19 | 1996-11-21 | Cornell Research Foundation, Inc. | Cascaded self-induced holography |
GB2302413B (en) * | 1995-06-20 | 1997-11-12 | Northern Telecom Ltd | Bragg gratings in waveguides |
GB2302599B (en) * | 1995-06-20 | 1998-08-26 | Northern Telecom Ltd | Forming Bragg gratings in photosensitive optical waveguides |
US5903690A (en) * | 1996-07-05 | 1999-05-11 | D-Star Technologies, Inc. | Method for changing the refraction index in germanium silicate glass |
US5620495A (en) * | 1995-08-16 | 1997-04-15 | Lucent Technologies Inc. | Formation of gratings in polymer-coated optical fibers |
JPH11511568A (en) | 1995-08-29 | 1999-10-05 | アロヨ・オプティクス・インコーポレイテッド | Optical coupler using wavelength selective diffraction grating |
US6236782B1 (en) | 1995-08-29 | 2001-05-22 | Arroyo Optics, Inc. | Grating assisted coupler devices |
US5875272A (en) * | 1995-10-27 | 1999-02-23 | Arroyo Optics, Inc. | Wavelength selective optical devices |
US5903689A (en) * | 1995-11-16 | 1999-05-11 | Institut National D'optique | Method for spatially controlling the period and amplitude of BRAGG filters |
US5748814A (en) * | 1995-11-16 | 1998-05-05 | Institut National D'optique | Method for spatially controlling the period and amplitude of Bragg filters |
FR2742881B1 (en) * | 1995-12-26 | 1998-02-06 | Alsthom Cge Alcatel | POINT-BY-POINT REGISTRATION METHOD AND SYSTEM OF A BRAGG NETWORK IN AN OPTICAL FIBER |
US5668901A (en) * | 1996-02-14 | 1997-09-16 | Corning Incorporated | Low reflectivity fiber bragg grating with rectangular reflection function |
US5896484A (en) * | 1996-02-15 | 1999-04-20 | Corning Incorporated | Method of making a symmetrical optical waveguide |
US5764829A (en) * | 1996-02-26 | 1998-06-09 | Lucent Technologies Inc. | Optical signal shaping device for complex spectral shaping applications |
US5708738A (en) * | 1996-03-05 | 1998-01-13 | The United States Of America As Represented By The Secretary Of The Navy | Apparatus and process for making fiber optic bragg gratings |
US6272886B1 (en) * | 1996-10-23 | 2001-08-14 | 3M Innovative Properties Company | Incremental method of producing multiple UV-induced gratings on a single optical fiber |
KR100318041B1 (en) | 1996-08-12 | 2001-12-24 | 와다 아끼히로 | Grating element, light wavelength selection utilizing the same, and optical signal transmitting system |
US6169830B1 (en) | 1996-08-26 | 2001-01-02 | Arroyo Optics, Inc. | Methods of fabricating grating assisted coupler devices |
US5773486A (en) * | 1996-09-26 | 1998-06-30 | Lucent Technologies Inc. | Method for the manufacture of optical gratings |
EP0996862A1 (en) * | 1996-12-30 | 2000-05-03 | D-Star Technologies, Inc. | Near-ultraviolet formation of refractive-index grating using phase mask |
US5745617A (en) * | 1996-12-30 | 1998-04-28 | D-Star Technologies, Llc | Near-ultra-violet formation of refractive-index grating using reflective phase mask |
CA2197706A1 (en) | 1997-02-14 | 1998-08-14 | Peter Ehbets | Method of fabricating apodized phase mask |
IT1292316B1 (en) * | 1997-05-20 | 1999-01-29 | Cselt Centro Studi Lab Telecom | PROCEDURE AND DEVICE FOR THE CREATION OF FIBER BRAGG GRATINGS OR OPTICAL WAVE GUIDES. |
US6093927A (en) * | 1997-06-09 | 2000-07-25 | Trw Inc. | Automated precision wavelength control for fiber optic Bragg grating writing |
FR2764394B1 (en) * | 1997-06-10 | 1999-08-06 | France Telecom | PHOTO REGISTRATION BENCH FOR BRAGG NETWORKS |
KR19990004127A (en) * | 1997-06-27 | 1999-01-15 | 윤종용 | Fiber Bragg Grating Fabricator |
US5953471A (en) * | 1997-07-01 | 1999-09-14 | Lucent Technologies, Inc. | Optical communication system having short period reflective Bragg gratings |
JP3526215B2 (en) * | 1997-07-03 | 2004-05-10 | 大日本印刷株式会社 | Phase mask for optical fiber processing and method of manufacturing the same |
US6728444B2 (en) * | 1997-10-02 | 2004-04-27 | 3M Innovative Properties Company | Fabrication of chirped fiber bragg gratings of any desired bandwidth using frequency modulation |
US6035083A (en) * | 1997-10-02 | 2000-03-07 | 3M Innovative Company | Method for writing arbitrary index perturbations in a wave-guiding structure |
CA2217806A1 (en) * | 1997-10-07 | 1999-04-07 | Mark Farries | Grating and method of providing a grating in an ion diffused waveguide |
GB9722550D0 (en) * | 1997-10-24 | 1997-12-24 | Univ Southampton | Fabrication of optical waveguide gratings |
WO1999027399A1 (en) * | 1997-11-26 | 1999-06-03 | Mitsubishi Cable Industries, Ltd. | Fiber grating, its manufacturing method and its manufacturing device |
CA2283403C (en) * | 1998-01-22 | 2009-05-19 | Dai Nippon Printing Co., Ltd. | Diffraction grating-fabricating phase mask, and its fabrication method |
US6055106A (en) * | 1998-02-03 | 2000-04-25 | Arch Development Corporation | Apparatus for applying optical gradient forces |
JP3869121B2 (en) | 1998-06-26 | 2007-01-17 | 古河電気工業株式会社 | Method for forming fiber grating |
JP2002529762A (en) * | 1998-10-30 | 2002-09-10 | コーニング インコーポレイテッド | Wavelength tuning of light-induced diffraction grating |
JP2000232248A (en) | 1999-02-10 | 2000-08-22 | Fujikura Ltd | Multi-wavelength exciting light multiplexing device, and multi-wavelength exciting light source and optical amplifier incooperating the device |
US6146713A (en) | 1999-03-25 | 2000-11-14 | Acme Grating Ventures, Llc | Optical transmission systems and apparatuses including Bragg gratings and methods of making |
JP3827883B2 (en) * | 1999-05-07 | 2006-09-27 | 三菱電線工業株式会社 | Optical fiber |
US7167615B1 (en) | 1999-11-05 | 2007-01-23 | Board Of Regents, The University Of Texas System | Resonant waveguide-grating filters and sensors and methods for making and using same |
JP2001242313A (en) | 2000-02-28 | 2001-09-07 | Dainippon Printing Co Ltd | Method of manufacturing phase mask for processing of optical fiber and optical fiber with bragg diffraction grating manufactured by using that phase mask for processing of optical fiber |
TW569041B (en) * | 2000-05-18 | 2004-01-01 | Sumitomo Electric Industries | Reflection-grid optical waveguide-path type and its production method |
KR100342493B1 (en) * | 2000-07-25 | 2002-06-28 | 윤종용 | Optical fiber grating fabricating apparatus for minimizing diffraction effect |
WO2002009483A1 (en) * | 2000-07-26 | 2002-01-31 | The Regents Of The University Of California | Manipulation of live cells and inorganic objects with optical micro beam arrays |
US6828262B2 (en) | 2000-07-31 | 2004-12-07 | Corning Incorporated | UV photosensitive melted glasses |
US6510264B2 (en) | 2000-07-31 | 2003-01-21 | Corning Incorporated | Bulk internal bragg gratings and optical devices |
US6632759B2 (en) | 2000-07-31 | 2003-10-14 | Corning Incorporated | UV photosensitive melted germano-silicate glasses |
US6731839B2 (en) | 2000-07-31 | 2004-05-04 | Corning Incorporated | Bulk internal Bragg gratings and optical devices |
KR100342532B1 (en) * | 2000-08-04 | 2002-06-28 | 윤종용 | Fabrication device of polarization insensitive long period fiber grating |
US6708741B1 (en) | 2000-08-24 | 2004-03-23 | Ocean Spray Cranberries, Inc. | Beverage dispenser |
US6744038B2 (en) | 2000-11-13 | 2004-06-01 | Genoptix, Inc. | Methods of separating particles using an optical gradient |
US6784420B2 (en) * | 2000-11-13 | 2004-08-31 | Genoptix, Inc. | Method of separating particles using an optical gradient |
US20030007894A1 (en) * | 2001-04-27 | 2003-01-09 | Genoptix | Methods and apparatus for use of optical forces for identification, characterization and/or sorting of particles |
US6936811B2 (en) * | 2000-11-13 | 2005-08-30 | Genoptix, Inc. | Method for separating micro-particles |
US6833542B2 (en) * | 2000-11-13 | 2004-12-21 | Genoptix, Inc. | Method for sorting particles |
US20020160470A1 (en) * | 2000-11-13 | 2002-10-31 | Genoptix | Methods and apparatus for generating and utilizing linear moving optical gradients |
US20020123112A1 (en) * | 2000-11-13 | 2002-09-05 | Genoptix | Methods for increasing detection sensitivity in optical dielectric sorting systems |
US6778724B2 (en) * | 2000-11-28 | 2004-08-17 | The Regents Of The University Of California | Optical switching and sorting of biological samples and microparticles transported in a micro-fluidic device, including integrated bio-chip devices |
US6694067B1 (en) | 2001-01-05 | 2004-02-17 | Los Gatos Research | Cavity enhanced fiber optic and waveguide chemical sensor |
US20040009540A1 (en) * | 2001-04-27 | 2004-01-15 | Genoptix, Inc | Detection and evaluation of cancer cells using optophoretic analysis |
US20030194755A1 (en) * | 2001-04-27 | 2003-10-16 | Genoptix, Inc. | Early detection of apoptotic events and apoptosis using optophoretic analysis |
US6693701B2 (en) * | 2001-05-29 | 2004-02-17 | Ibsen Photonics A/S | Method and apparatus for diffractive transfer of a mask grating |
CN1854778A (en) | 2001-06-20 | 2006-11-01 | 阿尔利克斯公司 | Optical switches and routers and optical filters |
US7006537B2 (en) * | 2001-08-07 | 2006-02-28 | Hrl Laboratories, Llc | Single polarization fiber laser |
JP3816769B2 (en) | 2001-09-03 | 2006-08-30 | 大日本印刷株式会社 | Manufacturing method of optical fiber processing phase mask, optical fiber processing phase mask, optical fiber with Bragg grating, and dispersion compensation device using the optical fiber |
US6768839B2 (en) | 2001-09-14 | 2004-07-27 | E. I. Du Pont De Nemours And Company | Tunable, polymeric core, fiber Bragg gratings |
US6842544B2 (en) * | 2001-09-14 | 2005-01-11 | E. I. Du Pont De Nemours And Company | Method for apodizing a planar waveguide grating |
CA2358659A1 (en) | 2001-10-09 | 2003-04-09 | Yves Painchaud | Bragg grating marking method using fringe control |
US6987909B1 (en) | 2001-11-30 | 2006-01-17 | Corvis Corporation | Optical systems and athermalized optical component apparatuses and methods for use therein |
CA2465292C (en) * | 2001-12-13 | 2006-10-10 | Institut National D'optique | Tunable phase mask assembly |
US6643066B2 (en) | 2001-12-13 | 2003-11-04 | Institut National D'optique | Tunable phase mask assembly |
US6654521B2 (en) * | 2002-01-23 | 2003-11-25 | Teraxion Inc. | Diffraction compensation of FBG phase masks for multi-channel sampling applications |
US20120019884A1 (en) * | 2003-03-17 | 2012-01-26 | Pd-Ld, Inc. | Bragg Grating Elements For Optical Devices |
US6724956B2 (en) * | 2002-04-03 | 2004-04-20 | Fitel Usa Corporation | Method and apparatus for providing dispersion compensation |
US20030211461A1 (en) * | 2002-05-01 | 2003-11-13 | Genoptix, Inc | Optophoretic detection of durgs exhibiting inhibitory effect on Bcr-Abl positive tumor cells |
US20040033539A1 (en) * | 2002-05-01 | 2004-02-19 | Genoptix, Inc | Method of using optical interrogation to determine a biological property of a cell or population of cells |
US6707976B1 (en) | 2002-09-04 | 2004-03-16 | Fitel Usa Corporation | Inverse dispersion compensating fiber |
US20040053209A1 (en) * | 2002-09-12 | 2004-03-18 | Genoptix, Inc | Detection and evaluation of topoisomerase inhibitors using optophoretic analysis |
US20040067167A1 (en) * | 2002-10-08 | 2004-04-08 | Genoptix, Inc. | Methods and apparatus for optophoretic diagnosis of cells and particles |
US20040121307A1 (en) * | 2002-12-19 | 2004-06-24 | Genoptix, Inc | Early detection of cellular differentiation using optophoresis |
US20040121474A1 (en) * | 2002-12-19 | 2004-06-24 | Genoptix, Inc | Detection and evaluation of chemically-mediated and ligand-mediated t-cell activation using optophoretic analysis |
US6842222B2 (en) * | 2003-04-04 | 2005-01-11 | Infineon Technologies Ag | Method of reducing pitch on semiconductor wafer |
US7745221B2 (en) * | 2003-08-28 | 2010-06-29 | Celula, Inc. | Methods and apparatus for sorting cells using an optical switch in a microfluidic channel network |
CA2502266A1 (en) * | 2004-03-26 | 2005-09-26 | Kyocera Corporation | External resonator and semiconductor laser module using the same |
DE102004049233A1 (en) * | 2004-10-09 | 2006-04-20 | Schott Ag | Process for the microstructuring of substrates made of flat glass |
US20080090158A1 (en) * | 2005-03-08 | 2008-04-17 | Teraxion Inc. | Method for designing an index profile suitable for encoding into a phase mask for manufacturing a complex optical grating |
US7352931B1 (en) | 2005-03-08 | 2008-04-01 | Teraxion Inc. | Method and phase mask for manufacturing a multi-channel optical grating |
US7257301B2 (en) * | 2005-03-31 | 2007-08-14 | Baker Hughes Incorporated | Optical fiber |
CA2548029A1 (en) * | 2006-05-23 | 2007-11-23 | Itf Laboratories Inc. | Method and system for writing fiber bragg grating having apodized spectrum on optical fibers |
KR100782879B1 (en) * | 2006-12-07 | 2007-12-06 | 한국전자통신연구원 | The fabrication device of optical fiber bragg grating and optical fiber and optical fiber laser including the optical fiber bragg grating |
TWI326773B (en) * | 2006-12-29 | 2010-07-01 | Ind Tech Res Inst | Improved optical fiber and the manufacturing method thereof |
US20090016686A1 (en) * | 2007-07-13 | 2009-01-15 | Nufern | Optical fiber gratings for handling increased power levels and methods of making |
EP3709061B1 (en) | 2009-08-19 | 2022-12-14 | Lawrence Livermore National Security, LLC | Method of fabricating and method of using a diffractive optic |
US8728719B2 (en) * | 2009-08-19 | 2014-05-20 | Lawrence Livermore National Security, Llc | Diffractive laser beam homogenizer including a photo-active material and method of fabricating the same |
DE102015119875A1 (en) | 2015-06-19 | 2016-12-22 | Laser- Und Medizin-Technologie Gmbh, Berlin | Lateral-emitting optical fibers and method for introducing micro-modifications into an optical waveguide |
JP6701458B2 (en) * | 2017-12-26 | 2020-05-27 | 三菱電機株式会社 | Light pattern generator |
US11245534B2 (en) | 2018-02-06 | 2022-02-08 | NB Research LLC | System and method for securing a resource |
NL2021258B1 (en) * | 2018-06-14 | 2019-12-20 | Illumina Inc | Device for luminescent imaging |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4749248A (en) * | 1985-11-06 | 1988-06-07 | American Telephone And Telegraph Company At&T Bell Laboratories | Device for tapping radiation from, or injecting radiation into, single made optical fiber, and communication system comprising same |
US4974930A (en) * | 1989-11-13 | 1990-12-04 | At&T Bell Laboratories | Mode scrambler with non-invasive fabrication in an optical fiber's cladding |
US5042897A (en) * | 1989-12-26 | 1991-08-27 | United Technologies Corporation | Optical waveguide embedded light redirecting Bragg grating arrangement |
US5066133A (en) * | 1990-10-18 | 1991-11-19 | United Technologies Corporation | Extended length embedded Bragg grating manufacturing method and arrangement |
-
1993
- 1993-01-14 US US08/004,770 patent/US5327515A/en not_active Expired - Lifetime
- 1993-12-08 EP EP93309849A patent/EP0606726B1/en not_active Expired - Lifetime
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JP3243102B2 (en) | 2002-01-07 |
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JPH06235808A (en) | 1994-08-23 |
EP0606726B1 (en) | 1999-07-14 |
DE69325640D1 (en) | 1999-08-19 |
EP0606726A2 (en) | 1994-07-20 |
CA2111808A1 (en) | 1994-07-15 |
US5327515A (en) | 1994-07-05 |
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