A six-channel wavelength multiplexer and demultiplexer for single mode systems

We have fabricated and evaluated the first single mode wavelength multiplexer based on a diffraction grating and strip waveguides. The waveguides were employed to minimize the physical spacing between inputs in order to maximize the ratio of channel width to channel separation. The center channel insertion losses for the six channel device were 6.4, 4.9, 6.0, 5.6, 6.8, and 7.8 dB at 1279, 1308, 1338, 1508, 1536, and 1566 nm, respectively. The 1-dB full channel widths averaged 6.0 nm. A matching demultiplexer with multi-mode outputs was also fabricated. The center channel insertion losses were 0.9, 1.1, 1.2, 1.7, 1.8, and 2.1 dB at 1278, 1310, 1337, 1505, 1533, and 1563 nm, respectively. Full 1-dB channel widths ranged from 15 to 11 nm. Out of band rejection exceeded 35 dB.