An asymmetric distributed Bragg reflector (DBR) suitable for use in vertical cavity surface emitting lasers. The asymmetric DBR is comprised of stacked material layers having different indexes of refraction that are joined using asymmetrical transition regions in which the transition steps within a transition...http://www.google.ca/patents/US20030123513?utm_source=gb-gplus-sharePatent US20030123513 - Assymmetric distributed bragg reflector for vertical cavity surface emitting lasers
