A dual wavelength (1.32-1.56 mu m) directional coupler demultiplexer by ion exchange in glass

A 1.32-1.56-μ m demultiplexer using a symmetrical directional coupler consisting of Ag/sup +/-Na/sup +/ exchanged channel waveguides in BK7 glass with a total insertion loss of 1.25 dB for a 14.5-mm-long device and a propagation loss of 0.15 dB/cm is demonstrated. The crosstalk at 1.315 and 1.561 mu m and the cross power ratio at 1.315 mu m were measured to be less than -40 dB for the TE mode.