Narrow-band ten-channel optical multiplexer and demultiplexer using a Fourier diffraction grating

A narrow-band ten-channel optical multiplexer and demultiplexer for densely spaced wavelength division multiplexing in multimode fiber communication systems are discussed. These devices consist of a Fourier diffraction grating having very high diffraction efficiency (85%), a telecentric lens system with low aberration, and a unique fiber array. The devices had a very narrow channel spacing of 1.9 nm and low dependence on polarizations in the range from 831.6 to 848.5 nm. The multiplexer had a bandwidth of 0.7 nm and the demultiplexer had a bandwidth of 1.1 nm.