Optical Couplers for Fiber to Integrated Optics Systems.

An optical coupler for transferring light or near IR radiation between high index integrated optics structures such as LiNbO3 and low loss optical fibers was developed. The design is a flexible glass fiber containing an external ridge guiding region on a larger lower index base material. Ridge dimensions down to 2 micrometers were obtained, indicating that single or multimode designs are possible. Special glasses which had refractive index values in excess of 2.20 at 632.9 nm were developed for the coupler fiber. The design utilizes evanescent wave coupling at the integrated optics structure and end fire coupling at the optical fiber. Author