Optical demultiplexing of a QPSK data channel into two BPSK sub-channels based on phase sensitive amplification

We demonstrate optical demultiplexing of a QPSK signal into two BPSK sub-channels based on coherent vector addition of original signal and the phase conjugated copy respectively. Both sub-channels of a QPSK signal are extracted simultaneously and independently using a scalable phase sensitive amplification technique. This phase sensitive method potentially may also be applied to higher level QAM signals.