OPTICAL DELAY-LINE INTERFEROMETER FOR DPSK AND DQPSK RECEIVERS FOR FIBER-OPTIC COMMUNICATION SYSTEMS

摘要

Some example embodiments of an interferometer for fiber optic communication systems include a pair of identical beam splitting prisms. Each of the beam splitting prisms includes a first total-internal-reflection surface, a second total-internal-reflection surface parallel to the first total-internal-reflection surface, and a beam splitting interface parallel to the first total-internal-reflection surface. An interferometer embodiment may optionally include a thermo-optic compensator disposed between the two beam splitting prisms. A beam splitting plate may optionally be included in some example embodiments to provide four spatially-separated output ports, two from each of two delay line interferometers sharing the two beam-splitting prisms. An alternative embodiment of an interferometer includes a beam splitting prism, a retro-reflective prism, and a beam splitting plate arranged to have four output ports spatially separated from one another, two of each port associated with a different one of two delay line interferometers sharing the beam splitting and retro-reflective prisms.