1.55-μm Sidewall Grating DFB Lasers Integrated With a Waveguide Crossing for an Optical Beam Forming Network

Abstract

By using asymmetric twin-waveguide technology, a 1.55-m sidewall grating distributed-feedback(DFB)laser monolithically integrated with a passive waveguide crossing was for the first time demonstrated for an optical beam forming network, which needs only one metalorganic vapor-phase epitaxy step. The DFB laser with uncoated facets presents a side-mode suppression ratio of >44 dB and a low 3-dB linewidth of 68 kHz. An elliptical parabolic taper waveguide crossing had a theoretical crosstalk suppression ratio of 40 dB, while the measured cross-talk suppression ratio was at least 20 dB.