Two Modes Unscrambling Using a Single Micro-Ring Resonator

We propose and demonstrate the use of one single micro-ring resonator (MRR) for unitary matrix operations. We proposed that a single MRR with two thermal tunable phase shifters can be used for 2 × 2 unitary conversion. For a proof-of-concept demonstration, a network composed of a 2d grating coupler and a MRR was designed and fabricated for polarization mode unscrambling. Specifically, we show that two arbitrarily mixed modes can be unscrambled to crosstalk levels below −19 dB. This paper shows how a single MRR may be used for matrix multiplications to process high-speed polarization-multiplexed communications signals with more compact footprint and modest power consumption.