Practical realization of a high density diode-coupled wavelength demultiplexer

The design, development, and optical performance of a novel demultiplexer in which a photodiode array replaces the array of fibers at the output is described. The prototype diode-coupler high-density wavelength demultiplexer has 16 channels with 4-nm channel spacing. Its optical performance, with respect to insertion loss, optical passband, total optical crosstalk, and polarization response and taking into account expected component and manufacturing tolerances is good. In particular, an optical passband between ±0.7 nm and ±0.9 nm can be tolerated without deterioration in performance, reducing the need for precise laser wavelength control. In addition, the diode leakage currents achieved, although relatively large, do not constitute a significant penalty in receiver sensitivity for applications at 560 Mb/s or higher, and the diode capacitance is very low. It is concluded that this is an attractive solution for high-density wavelength-division multiplexing