CA2237963C - A method of and a device for making bragg gratings in optical fibres or waveguides - Google Patents
A method of and a device for making bragg gratings in optical fibres or waveguides Download PDFInfo
- Publication number
- CA2237963C CA2237963C CA002237963A CA2237963A CA2237963C CA 2237963 C CA2237963 C CA 2237963C CA 002237963 A CA002237963 A CA 002237963A CA 2237963 A CA2237963 A CA 2237963A CA 2237963 C CA2237963 C CA 2237963C
- Authority
- CA
- Canada
- Prior art keywords
- waveguides
- radiation
- reciprocation
- fibres
- gratings
- 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.)
- Expired - Fee Related
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 title claims abstract description 16
- 230000005855 radiation Effects 0.000 claims abstract description 31
- 238000009826 distribution Methods 0.000 claims abstract description 7
- 238000004519 manufacturing process Methods 0.000 claims abstract description 5
- 230000008859 change Effects 0.000 claims abstract description 4
- 230000000737 periodic effect Effects 0.000 claims description 6
- 230000008676 import Effects 0.000 claims 1
- 239000007787 solid Substances 0.000 claims 1
- 239000000835 fiber Substances 0.000 abstract description 16
- 230000008878 coupling Effects 0.000 description 5
- 238000010168 coupling process Methods 0.000 description 5
- 238000005859 coupling reaction Methods 0.000 description 5
- 239000013307 optical fiber Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000005286 illumination Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 206010034972 Photosensitivity reaction Diseases 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical class O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000005352 clarification Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 238000001093 holography Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000036211 photosensitivity 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
-
- 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
- G02B6/02152—Refractive index modulation gratings, e.g. Bragg gratings characterised by the method of manufacture of the grating involving moving the fibre or a manufacturing element, stretching of the fibre
Abstract
A method and a device are described for the simultaneous fabrication of identical Bragg gratings in different optical fibres or optical waveguides. The fibres/waveguides (1) are mounted side-by-side on a common support (2), along with a phase mask (3), which gives the desired intensity distribution to a writing radiation of the grating. Said common support (2) is reciprocated transversally to the longitudinal axis of the fibres or waveguides, at an appropriately low frequency such that each fibre/waveguide is exposed to such a radiation, at each pass under the radiation, for a time sufficient to start a refractive index change.
Description
CA 02237963 1998-0~-19 A METHOD OF AND A DEVICE FOR MAKING BRAGG GRATINGS IN OPTICAL
This invention relates to the fabrication of optical fibre components for optical telecommunications, and more specifically its object is to provide a method of and a device for making identical Bragg gratings in separate photosensitive optical fibres or 20 waveguides.
In optical telecommunication systems use is commonly made of wavelength selective optical components that are based on Bragg gratings made in an optical fibre or planar waveguide and that exploit the fact that a Bragg grating with a given pitch reflects a certain wavelength and transmits the other wavelengths. Said gratings are 25 made of spans of fibre or waveguide that show periodic refractive index changes along their length. A commonly used technique for obtaining these periodic refractive index changes is to illuminate the fibre or the waveguide with an interference fringe pattern obtained through holography or through direct interference between two UV beams or by means of a mask on which a grating has been made which spatially modulates a 30 characteristic of the radiation sent to the fibre or waveguide, e.g. its phase.
In some applications, e.g. for making band pass filters or devices for wavelength insertion-extraction (Add-Drop Multiplexers) it is necessary to make pairs of absolutely identical gratings in both branches of an optical waveguide coupler. In its basic structure, an optical waveguide coupler is formed by two portions of fibre or guide, 35 which are joined in their middle part (coupling region), as depicted in Figure 1. In order to obtain a grating device of the kind mentioned before, a grating is made in each of the two fibre or waveguide portions (in the region where they are separate), so that the CA 02237963 1998-0~-19 radiation at the wavelength of interest, sent through a coupler branch (for instance, branch 100A), is reflected by both gratings and goes out through one of the other branches, at the same end from which it has been launched (e.g. through branch 101 B). If the two gratings are not substantially identical, a non-negligible percentage of S such a radiation is reflected towards the input branch, causing disturbances. The term "substantially identical" means here that the spectral response curves must coincide to an extent greater than 90% in the band of interest, in order to keep the unwanted reflection below 10%.
It is extremely difficult to make identical gratings on separate fibres or 10 waveguides by separately writing the gratings on each fibre or guide. As a matter of fact, the characteristics of the sources by which the fibres or guides are illuminated to make such gratings may vary with time and it is therefore difficult to guarantee that all characteristics are still substantially identical at the end of the grating writing into a fibre or guide, when passing to another fibre or guide. On the other hand, the core of a 15 guide (and especially of a fibre) is of particularly small dimensions (a few micron diameter) and it is therefore also difficult to guarantee the same relative position between the different fibres or guides and the optical system focusing the writing radiation.
A different approach is to irradiate the fibres or waveguides by means of a beam20 that has such a width as to illuminate the cores of all fibres or waveguides. In this case, too, it appears rather difficult to ensure a uniform illumination of all fibres or waveguides by the beam. Besides, the process time becomes longer, and work benchvibrations might occur, which would affect the overall quality.
The present invention aims to provide a method and a device which allow such 25 uniform illumination of all fibres or guides involved in grating writing.
The invention concerns a method wherein the optical fibres or waveguides are exposed, for a portion of their lengths, to a radiation whose intensity distribution is such as to cause periodic refractive index changes in the irradiated fibre or waveguide portion and wherein, for making identical gratings on multiple fibres or waveguides, 30 such fibres or waveguides are located side-by-side and are jointly subjected to a reciprocation transversally to their longitudinal axis, at such a low frequency that, at each pass under the radiation, each fibre or waveguide is exposed to the radiation for a time sufficient to ensure an adequate change in their refractive index.
The present invention also concerns a device for carrying out the process, 35 wherein a source sends towards the fibres or waveguides, through an optical system, a radiation which at its incidence onto the fibres or waveguides shows an intensity distribution such as to originate periodic refractive index changes in the irradiated CA 02237963 1998-0~-19 zone, and wherein, to make identical gratings on multiple fibres or waveguides, these are mounted side-by-side on a common support, associated to means for causing its reciprocation transversally to the longitudinal axis of the waveguides, at such a low frequency that, at each pass under the radiation, each waveguide remains exposed to 5 the radiation for a time sufficient to ensure the refractive index change.
The paper "High-Return Loss Narrowband All-Fibre Bandpass Bragg Transmission Filter, by F. Bilodeau et al., IEEE Photonics Technology Letter, Vol. 6, No 1, January 1994, pages 80-82, discloses a filter based on a coupler like thatpreviously described herein, and states that the filter has a high return loss (30 dB or 10 more) due to the presence of two substantially identical gratings, simultaneously written in both fibres, downstream of the coupling zone with reference to the direction along which the radiation is sent into the filter. No information is given about the approach followed to solve the problem of ensuring uniform irradiation of both fibres during their simultaneous writing.
Also GB-A 2283831 discloses a coupler in which gratings are made in a zone located downstream of the coupling region and states that such gratings are simultaneously written and are substantially identical or form a single grating.Nevertheless, no information is provided about the way such identity is guaranteed.
For the sake of further clarification, reference is made to the accompanying drawings, wherein:
- Figure 1 shows an optical coupler with gratings; and - Figure 2 shows a device for carrying out the method according to this invention.
With reference to Figure 1, a coupler in fibre or waveguide that can be used in grating devices, such as band pass filters or add-drop multiplexers, is formed by two portions of optical fibre or waveguide, which are joined in the central part and form the four branches 100A, 100B, 101A, 101B of the coupler.
The central part 102 forms the coupling region. Both fibres or waveguides have agrating 103, 104, located downstream of coupling region 102, so that the radiation at the wavelength of interest, sent through a coupler branch (e.g. branch 100A), isreflected by both gratings 103,104 and goes out through one of the other branches (in Figure, branch 101B), on the same side where it has been launched. Both gratingsmust be substantially identical (i.e. must have spectral response curves which, in the band of interest, coincide by more than 90%) in order to minimise the percentage of incident radiation which is reflected towards input branch 100A, causing disturbances.
In Figure 2 a device suitable for fabricating identical gratings on a group of fibres 1 is depicted. Fibres 1 are mounted in a support 2, which also carries a phase mask 3.
This support must guarantee that the position of fibres 1 relative to phase mask 3 CA 02237963 1998-0~-19 remains constant with time. In a conventional way, phase mask 3 is illuminated by the UV radiation emitted by a laser 4, through an optical system capable of creating onto the phase mask an image of the source formed by a thin strip of the same length as the grating to be fabricated.
The optical system includes, in known manner, a first lens 5 to expand the beam emitted by the source; a group of lenses 6,7,8 to generate a collimated beam; a diaphragm 9 between lenses 6,7 to shape the beam, giving it for instance a t'~Ussi~n intensity distribution; a cylindrical lens 10 to form the source image on phase mask 3.
Advantageously, the radiation emitted by source 4 is sent towards the optical 10 system through a pair of mirrors 11,12, which allow obtaining, between source 4 and phase mask 3, a sufficiently long path to make the secondary mode effect negligible and at the same time allow keeping the device to a small size.
For the fabrication of identical gratings on the different fibres 1, support 2 is mounted on a guide (not depicted), perpendicular to the longitudinal axis of the fibres, lS along which guide said support can be reciprocated, for instance under the control of a motor 13, so as to cause the UV radiation to scan the fibres. Scanning of the fibres determines that at each pass under the radiation said fibres substantially receive the same beam, thus obtaining the actual identity of the gratings being fabricated and avoiding problems due for instance to an alignment between fibres 1 and optical 20 system 5 - 10 which might be not completely accurate. To guarantee this, it is advantageous that laser 4 be a continuous wave laser; also a pulsed laser can beused, such an excimer laser, but it must show a high pulse repetition rate, e.g. a rate higher than one hundred Hz ~e.g. 100 - 150 Hz).
The frequency of the reciprocation and the overall duration of irradiation are 25 dependent on the source power, on the photosensitivy characteristics of the fibres as well as on the number of fibres into which the gratings are to be written. In any case such frequency shall have to be sufficiently low as to guarantee that each fibre, at each step, remains exposed for a sufficient time such as to ensure the start of the refractive index variation: thanks to the repeated passages of each fibre before the 30 irradiating beam, an integration in time is then obtained of the irradiated power so that at the process end the refractive index differences actually needed for a grating are obtained.
In an exemplary embodiment of this invention, in which the gratings have been written on conventional hydrogenated silica fibres, reciprocation frequencies of 1 Hz or 35 less have proven as adequate; values lower than 1 Hz are required in particular if a pulsed laser is used. By using a continuous wave laser with a power of the order of a few hundred mW (e.g. 500 mW), the fabrication of the gratings on a pair of fibres has CA 02237963 1998-0~-19 required a few minutes, which time is quite compatible with industrial production requirements. Said time can be cut down if use is made of laser of higher power (1- 2 W) or of fibres having a higher photosensitivity with respect to conventional fibres (e.g.
fibres doped with Germanium in high concentrations and/or having particular refractive 5 index distributions).
It is evident that the description above is provided purely by way of a non limiting example and that variations and/or modifications are possible without thereby departing from the scope of the invention itself. For instance, even if Fig. 2 shows a group of fibres, the description applies also to the case of planar waveguides: in 10 particular, in the case of a waveguide coupler in which the two waveguides are fabricated on a some wafer, the wafer will be mounted on support 2.
This invention relates to the fabrication of optical fibre components for optical telecommunications, and more specifically its object is to provide a method of and a device for making identical Bragg gratings in separate photosensitive optical fibres or 20 waveguides.
In optical telecommunication systems use is commonly made of wavelength selective optical components that are based on Bragg gratings made in an optical fibre or planar waveguide and that exploit the fact that a Bragg grating with a given pitch reflects a certain wavelength and transmits the other wavelengths. Said gratings are 25 made of spans of fibre or waveguide that show periodic refractive index changes along their length. A commonly used technique for obtaining these periodic refractive index changes is to illuminate the fibre or the waveguide with an interference fringe pattern obtained through holography or through direct interference between two UV beams or by means of a mask on which a grating has been made which spatially modulates a 30 characteristic of the radiation sent to the fibre or waveguide, e.g. its phase.
In some applications, e.g. for making band pass filters or devices for wavelength insertion-extraction (Add-Drop Multiplexers) it is necessary to make pairs of absolutely identical gratings in both branches of an optical waveguide coupler. In its basic structure, an optical waveguide coupler is formed by two portions of fibre or guide, 35 which are joined in their middle part (coupling region), as depicted in Figure 1. In order to obtain a grating device of the kind mentioned before, a grating is made in each of the two fibre or waveguide portions (in the region where they are separate), so that the CA 02237963 1998-0~-19 radiation at the wavelength of interest, sent through a coupler branch (for instance, branch 100A), is reflected by both gratings and goes out through one of the other branches, at the same end from which it has been launched (e.g. through branch 101 B). If the two gratings are not substantially identical, a non-negligible percentage of S such a radiation is reflected towards the input branch, causing disturbances. The term "substantially identical" means here that the spectral response curves must coincide to an extent greater than 90% in the band of interest, in order to keep the unwanted reflection below 10%.
It is extremely difficult to make identical gratings on separate fibres or 10 waveguides by separately writing the gratings on each fibre or guide. As a matter of fact, the characteristics of the sources by which the fibres or guides are illuminated to make such gratings may vary with time and it is therefore difficult to guarantee that all characteristics are still substantially identical at the end of the grating writing into a fibre or guide, when passing to another fibre or guide. On the other hand, the core of a 15 guide (and especially of a fibre) is of particularly small dimensions (a few micron diameter) and it is therefore also difficult to guarantee the same relative position between the different fibres or guides and the optical system focusing the writing radiation.
A different approach is to irradiate the fibres or waveguides by means of a beam20 that has such a width as to illuminate the cores of all fibres or waveguides. In this case, too, it appears rather difficult to ensure a uniform illumination of all fibres or waveguides by the beam. Besides, the process time becomes longer, and work benchvibrations might occur, which would affect the overall quality.
The present invention aims to provide a method and a device which allow such 25 uniform illumination of all fibres or guides involved in grating writing.
The invention concerns a method wherein the optical fibres or waveguides are exposed, for a portion of their lengths, to a radiation whose intensity distribution is such as to cause periodic refractive index changes in the irradiated fibre or waveguide portion and wherein, for making identical gratings on multiple fibres or waveguides, 30 such fibres or waveguides are located side-by-side and are jointly subjected to a reciprocation transversally to their longitudinal axis, at such a low frequency that, at each pass under the radiation, each fibre or waveguide is exposed to the radiation for a time sufficient to ensure an adequate change in their refractive index.
The present invention also concerns a device for carrying out the process, 35 wherein a source sends towards the fibres or waveguides, through an optical system, a radiation which at its incidence onto the fibres or waveguides shows an intensity distribution such as to originate periodic refractive index changes in the irradiated CA 02237963 1998-0~-19 zone, and wherein, to make identical gratings on multiple fibres or waveguides, these are mounted side-by-side on a common support, associated to means for causing its reciprocation transversally to the longitudinal axis of the waveguides, at such a low frequency that, at each pass under the radiation, each waveguide remains exposed to 5 the radiation for a time sufficient to ensure the refractive index change.
The paper "High-Return Loss Narrowband All-Fibre Bandpass Bragg Transmission Filter, by F. Bilodeau et al., IEEE Photonics Technology Letter, Vol. 6, No 1, January 1994, pages 80-82, discloses a filter based on a coupler like thatpreviously described herein, and states that the filter has a high return loss (30 dB or 10 more) due to the presence of two substantially identical gratings, simultaneously written in both fibres, downstream of the coupling zone with reference to the direction along which the radiation is sent into the filter. No information is given about the approach followed to solve the problem of ensuring uniform irradiation of both fibres during their simultaneous writing.
Also GB-A 2283831 discloses a coupler in which gratings are made in a zone located downstream of the coupling region and states that such gratings are simultaneously written and are substantially identical or form a single grating.Nevertheless, no information is provided about the way such identity is guaranteed.
For the sake of further clarification, reference is made to the accompanying drawings, wherein:
- Figure 1 shows an optical coupler with gratings; and - Figure 2 shows a device for carrying out the method according to this invention.
With reference to Figure 1, a coupler in fibre or waveguide that can be used in grating devices, such as band pass filters or add-drop multiplexers, is formed by two portions of optical fibre or waveguide, which are joined in the central part and form the four branches 100A, 100B, 101A, 101B of the coupler.
The central part 102 forms the coupling region. Both fibres or waveguides have agrating 103, 104, located downstream of coupling region 102, so that the radiation at the wavelength of interest, sent through a coupler branch (e.g. branch 100A), isreflected by both gratings 103,104 and goes out through one of the other branches (in Figure, branch 101B), on the same side where it has been launched. Both gratingsmust be substantially identical (i.e. must have spectral response curves which, in the band of interest, coincide by more than 90%) in order to minimise the percentage of incident radiation which is reflected towards input branch 100A, causing disturbances.
In Figure 2 a device suitable for fabricating identical gratings on a group of fibres 1 is depicted. Fibres 1 are mounted in a support 2, which also carries a phase mask 3.
This support must guarantee that the position of fibres 1 relative to phase mask 3 CA 02237963 1998-0~-19 remains constant with time. In a conventional way, phase mask 3 is illuminated by the UV radiation emitted by a laser 4, through an optical system capable of creating onto the phase mask an image of the source formed by a thin strip of the same length as the grating to be fabricated.
The optical system includes, in known manner, a first lens 5 to expand the beam emitted by the source; a group of lenses 6,7,8 to generate a collimated beam; a diaphragm 9 between lenses 6,7 to shape the beam, giving it for instance a t'~Ussi~n intensity distribution; a cylindrical lens 10 to form the source image on phase mask 3.
Advantageously, the radiation emitted by source 4 is sent towards the optical 10 system through a pair of mirrors 11,12, which allow obtaining, between source 4 and phase mask 3, a sufficiently long path to make the secondary mode effect negligible and at the same time allow keeping the device to a small size.
For the fabrication of identical gratings on the different fibres 1, support 2 is mounted on a guide (not depicted), perpendicular to the longitudinal axis of the fibres, lS along which guide said support can be reciprocated, for instance under the control of a motor 13, so as to cause the UV radiation to scan the fibres. Scanning of the fibres determines that at each pass under the radiation said fibres substantially receive the same beam, thus obtaining the actual identity of the gratings being fabricated and avoiding problems due for instance to an alignment between fibres 1 and optical 20 system 5 - 10 which might be not completely accurate. To guarantee this, it is advantageous that laser 4 be a continuous wave laser; also a pulsed laser can beused, such an excimer laser, but it must show a high pulse repetition rate, e.g. a rate higher than one hundred Hz ~e.g. 100 - 150 Hz).
The frequency of the reciprocation and the overall duration of irradiation are 25 dependent on the source power, on the photosensitivy characteristics of the fibres as well as on the number of fibres into which the gratings are to be written. In any case such frequency shall have to be sufficiently low as to guarantee that each fibre, at each step, remains exposed for a sufficient time such as to ensure the start of the refractive index variation: thanks to the repeated passages of each fibre before the 30 irradiating beam, an integration in time is then obtained of the irradiated power so that at the process end the refractive index differences actually needed for a grating are obtained.
In an exemplary embodiment of this invention, in which the gratings have been written on conventional hydrogenated silica fibres, reciprocation frequencies of 1 Hz or 35 less have proven as adequate; values lower than 1 Hz are required in particular if a pulsed laser is used. By using a continuous wave laser with a power of the order of a few hundred mW (e.g. 500 mW), the fabrication of the gratings on a pair of fibres has CA 02237963 1998-0~-19 required a few minutes, which time is quite compatible with industrial production requirements. Said time can be cut down if use is made of laser of higher power (1- 2 W) or of fibres having a higher photosensitivity with respect to conventional fibres (e.g.
fibres doped with Germanium in high concentrations and/or having particular refractive 5 index distributions).
It is evident that the description above is provided purely by way of a non limiting example and that variations and/or modifications are possible without thereby departing from the scope of the invention itself. For instance, even if Fig. 2 shows a group of fibres, the description applies also to the case of planar waveguides: in 10 particular, in the case of a waveguide coupler in which the two waveguides are fabricated on a some wafer, the wafer will be mounted on support 2.
Claims (12)
1. Method of making Bragg gratings in single mode optical waveguides (1), in which the waveguides (1) are exposed for a portion of their length to the action of a radiation with an intensity distribution such as to cause periodic refractive index changes along the irradiated zone, characterised in that, for making identical gratings on multiple waveguides (1), said waveguides (1) are located side-by-side and are jointly subjected to a reciprocation transversal to their longitudinal axis, at such a low frequency that, at each pass under the radiation, each waveguide remains exposed to the radiation for a time sufficient to start the refractive index variation.
2. Method as claimed in claim 1, in which said radiation is sent onto the waveguides (1) by means of a phase mask (3), characterised in that said mask (3) is subjected to the reciprocation jointly with the waveguides (1).
3. Method as claimed in claim 1 or 2, characterised in that such reciprocation has a frequency of the order of 1 Hz or less.
4. Method as claimed in any of claims 1 to 3, characterised in that said radiation is a continuous radiation.
5. Method as claimed in any of claims 1 to 3, characterised in that such a radiation is a pulsed radiation with a pulse repetition rate much higher than the frequency of the reciprocation.
6. Method as claimed in claim 5, characterised in that the pulse repetition rate is at least 100 Hz.
7. Device for making Bragg gratings in optical waveguides, in which a source (4)sends towards the waveguides (1) through an optical system (5 - 10) a radiation which at its incidence on the waveguides (1) has an intensity distribution such as to cause periodic refractive index changes in the irradiated zone, characterised in that, to make identical gratings on multiple waveguides (1), said waveguides aremounted side-by-side on a common support (2) associated with means (13) to import it a reciprocation transversal to the longitudinal axis of the waveguides (1), at such a low frequency that, at each pass under the radiation, each waveguide remains exposed to the radiation for a sufficient time so as to start the refractive index change.
8. Device as claimed in claim 7, characterised in that said support (2) also carries a phase mask (3), solid with the waveguides (1).
9. Device as claimed in claim 7 or 8, characterised in that the means (13) for causing a reciprocation of said support (2) are arranged to induce a motion at a frequency of the order of 1 Hz or less.
10. Device as claimed in any of claims 7 to 9, characterised in that the source (4) is a continuous wave source.
11. Device as claimed in any of claims 7 to 9, characterised in that source (4) is a pulsed source, with a pulse repetition rate much higher than the frequency of the reciprocation.
12. Device as claimed in claim 11, characterised in that the pulse repetition rate is at least 100 Hz.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ITTO97A000424 | 1997-05-20 | ||
| IT97TO000424A IT1292316B1 (en) | 1997-05-20 | 1997-05-20 | PROCEDURE AND DEVICE FOR THE CREATION OF FIBER BRAGG GRATINGS OR OPTICAL WAVE GUIDES. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2237963A1 CA2237963A1 (en) | 1998-11-20 |
| CA2237963C true CA2237963C (en) | 2002-07-09 |
Family
ID=11415715
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002237963A Expired - Fee Related CA2237963C (en) | 1997-05-20 | 1998-05-19 | A method of and a device for making bragg gratings in optical fibres or waveguides |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5953472A (en) |
| EP (1) | EP0880042B1 (en) |
| JP (1) | JP2920762B2 (en) |
| CA (1) | CA2237963C (en) |
| DE (2) | DE880042T1 (en) |
| IT (1) | IT1292316B1 (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU761179B2 (en) * | 1998-10-30 | 2003-05-29 | Corning Incorporated | Wavelength tuning of photo-induced gratings |
| US6249624B1 (en) * | 1998-12-04 | 2001-06-19 | Cidra Corporation | Method and apparatus for forming a Bragg grating with high intensity light |
| IT1305114B1 (en) * | 1998-12-21 | 2001-04-10 | Cselt Centro Studi Lab Telecom | PROCEDURE FOR MAKING FIBER OPTIC RETICLES AND RELATED DEVICE. |
| JP2000249819A (en) * | 1999-02-26 | 2000-09-14 | Mitsubishi Electric Corp | Method and device for production of grating |
| KR100334812B1 (en) | 1999-07-02 | 2002-05-02 | 윤종용 | Apodized fiber grating fabricating system |
| KR100334799B1 (en) * | 1999-07-07 | 2002-05-02 | 윤종용 | Apparatus and method for fabricating fiber grating |
| US6690685B1 (en) * | 1999-09-29 | 2004-02-10 | Corning O.T.I., Spa | Method for producing a fiber laser |
| KR100315671B1 (en) * | 1999-12-28 | 2001-11-29 | 윤종용 | Apparatus and method for fabricating multi-period optical fiber grating |
| US6522808B1 (en) * | 2000-01-15 | 2003-02-18 | Corning Incorporated | System and method for writing fiber gratings and other components |
| KR100342493B1 (en) * | 2000-07-25 | 2002-06-28 | 윤종용 | Optical fiber grating fabricating apparatus for minimizing diffraction effect |
| US6603559B2 (en) * | 2001-10-11 | 2003-08-05 | Yuan Ze University | Silicon-on-insulator optical waveguide Michelson interferometer sensor for temperature monitoring |
| DE102009005972B4 (en) | 2009-01-23 | 2011-06-16 | Laser-Laboratorium Göttingen eV | Method for generating a periodic pattern |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0191063B1 (en) * | 1984-08-13 | 1992-05-13 | United Technologies Corporation | Method for impressing grating within fiber optics |
| US5093876A (en) * | 1990-07-27 | 1992-03-03 | At&T Bell Laboratories | WDM systems incorporating adiabatic reflection filters |
| US5327515A (en) * | 1993-01-14 | 1994-07-05 | At&T Laboratories | Method for forming a Bragg grating in an optical medium |
| US5459801A (en) * | 1993-10-29 | 1995-10-17 | Rutgers University | Coupler used to fabricate add-drop devices, dispersion compensators, amplifiers, oscillators, superluminescent devices, and communications systems |
| GB2283831B (en) * | 1993-11-10 | 1996-11-06 | Northern Telecom Ltd | Optical fibre elements |
| GB2297656A (en) * | 1995-02-01 | 1996-08-07 | Northern Telecom Ltd | Optical filtering |
| US5620495A (en) * | 1995-08-16 | 1997-04-15 | Lucent Technologies Inc. | Formation of gratings in polymer-coated optical fibers |
| GB2308252B (en) * | 1995-12-16 | 2000-02-23 | Northern Telecom Ltd | WDM channel insertion |
-
1997
- 1997-05-20 IT IT97TO000424A patent/IT1292316B1/en active IP Right Grant
-
1998
- 1998-04-27 US US09/067,515 patent/US5953472A/en not_active Expired - Lifetime
- 1998-05-15 DE DE0880042T patent/DE880042T1/en active Pending
- 1998-05-15 JP JP10150777A patent/JP2920762B2/en not_active Expired - Fee Related
- 1998-05-15 EP EP98108857A patent/EP0880042B1/en not_active Expired - Lifetime
- 1998-05-15 DE DE69827070T patent/DE69827070T2/en not_active Expired - Fee Related
- 1998-05-19 CA CA002237963A patent/CA2237963C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE69827070D1 (en) | 2004-11-25 |
| JP2920762B2 (en) | 1999-07-19 |
| DE69827070T2 (en) | 2006-03-09 |
| EP0880042B1 (en) | 2004-10-20 |
| EP0880042A2 (en) | 1998-11-25 |
| IT1292316B1 (en) | 1999-01-29 |
| US5953472A (en) | 1999-09-14 |
| CA2237963A1 (en) | 1998-11-20 |
| ITTO970424A1 (en) | 1998-11-20 |
| ITTO970424A0 (en) | 1997-05-20 |
| EP0880042A3 (en) | 1999-02-24 |
| DE880042T1 (en) | 1999-07-22 |
| JPH10319255A (en) | 1998-12-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2307189C (en) | Fabrication of optical waveguide gratings | |
| US5764829A (en) | Optical signal shaping device for complex spectral shaping applications | |
| EP0694172B1 (en) | Method of producing a bragg grating in an optical waveguide | |
| US5604829A (en) | Optical waveguide with diffraction grating and method of forming the same | |
| KR100425568B1 (en) | Grating | |
| US6081640A (en) | Broadband grating | |
| FR2697642A1 (en) | Method of making Bragg diffraction gratings. | |
| CA2237963C (en) | A method of and a device for making bragg gratings in optical fibres or waveguides | |
| CA2652823A1 (en) | Optical devices and digital laser method for writing waveguides, gratings, and integrated optical circuits | |
| EP0881515B1 (en) | Spatial filter for high power laser beam | |
| AU763596B2 (en) | Apparatus for manufacturing long-period fiber gratings and apparatus for manufacturing two-band long-period fiber gratings using the same | |
| CN212872967U (en) | Apodization long period optical fiber grating inscribing device | |
| US5708739A (en) | Method and apparatus for photobleaching patterns in irradiated optical waveguides | |
| KR20010008723A (en) | Apodized fiber grating fabricating system | |
| US20020076131A1 (en) | Method and apparatus for frequency tuning of an unbalanced Mach-Zehnder interferometer | |
| KR20010028469A (en) | Apparatus for fabricating long-period optical fiber grating | |
| JP4034041B2 (en) | Manufacturing method of optical waveguide grating | |
| JP2001141943A (en) | Method for forming grating | |
| AU678892B2 (en) | Optical grating | |
| JPH1062636A (en) | Method of forming bragg diffraction grating | |
| CA2372939A1 (en) | Bragg grating made in optical waveguide | |
| JP2003167138A (en) | Method and device for forming grating | |
| JP2000249849A (en) | Manufacture of optical waveguide having grating formed | |
| JP2005221530A (en) | Device for manufacturing grating device, and manufacturing method | |
| JPH08286010A (en) | Device for forming chirp grating |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |