MONOLITHIC INTEGRATED OPTICAL AMPLIFIER AND PHOTODETECTOR

摘要

An optical amplifier and photodetector are monolithically integrated, with the photodetector being optically coupled to the optical amplifier through a low rad iative loss and low back reflectivity branching waveguide. Because of the low reflectiv ity, the branching waveguide, although having a truncated wedge tip, is able to redir ect a small portion of optical radiation from the amplifier to the photodetector witho ut deleteriously effecting the performance of the optical amplifier. The branching waveguide is realized by employing between the branches of the waveguide, a junction region having a gradual decrease in effective refractive index such as to decrease the difference between the refractive indices at the optical interface of the truncated wedge tip as seen by optical radiation incident thereto from the optic al amplifier.