Low-crosstalk, short-length mismatched optical coupler designed by new weighting function

A newly self-developed weighting function called Chen weighting function is disclosed to show that the excellent results are obtained to compare with the Blackman and Hamming weighting function in applying to the waveguide structure of mismatched optical couplers for the demand of short-length, C+L-band, and low crosstalk. It is found that the coupler with a coupling length of 2.5 mm and crosstalk of −35 dB can reach the bandwidths within 1.360 ∼ 1.700 µm.