Polarization-independent EML-based coherent detection with fading-resistant carrier and Alamouti-coded signal

We propose a simple polarization-independent coherent detection scheme for cost-sensitive short to medium reach applications. The Alamouti-coded signal is generated in a dual-polarization transmitter and received by an electro-absorption modulated laser (EML) for arbitrary incoming polarization states. To obtain a stable local oscillator, dual-polarization optical carriers are also utilized for injection locking operation, with phase modulation applied to one of the orthogonal polarization states to prevent carrier fading. A proof-of-concept experiment for an 8-GBaud quadrature phase shift keying single-sideband signal over 80-km fiber transmission is conducted, demonstrating the polarization-independent operation of the EML-based coherent receiver.