A high-density wavelength-division multiplexer allows 131 different wavelengths to be combined at the sending end, carried by a single optical fiber and separated at the receiving end into 131 fibers. Crosstalk is better than -50 dB, and wavelength separation from channel to channel can be as little as 0.25 nm at a mean carrier wavelength of 1550 nm. Thermally induced wavelength drift is 0.012 nm/°C if the device is not in a temperature-regulated housing and 0.0004 nm/°C when regulated. The device is essentially a block of glass with a diffraction grating formed at one end and a curved mirror at the opposite end.
Instruments S.A. Inc.