Nonreciprocal Polarization Conversion in Asymmetric Magnetooptic Waveguide

A nonreciprocal polarization converter compatible with InP photonic integrated circuits is demonstrated. The device consists of an asymmetric InGaAsP waveguide combined with a ferrimagnetic Ce:YIG layer. It makes use of the direction dependence of the propagation of light in the waveguide. A trial device was made using orientation-dependent etching of InGaAsP and wafer-bonding of YIG to InGaAsP. It showed a nonreciprocal TE-TM conversion efficiency of 38% at 1.55 μm wavelength.