Optical 90 degree hybrid with broad operating bandwidth of 94 nm

Opt Lett. 2009 Nov 15;34(22):3505-7. doi: 10.1364/OL.34.003505.

Abstract

We propose an optical 90 degree hybrid where no waveguide intersection in coupling to balanced photodiodes is required for coherent detection. The proposed device consisting of a paired-interference 2x4 multimode interference (MMI) coupler, a phase shifter, and a 2x2 MMI coupler exhibited quadrature phase response over a 94-nm-wide spectral range.