Blind Level Discrimination Carrier Recovery Algorithm for 16-QAM optical coherent communication system

We propose and demonstrate a new blind carrier recovering technique, named, Level Discrimination Carrier Recovery Algorithm (LD-CRA) for optical coherent receiver. Our proposed single tap LD-CRA can blindly compensate the laser phase noise without using any training sequence. Our analysis result found that for 300 KHz linewidth laser, the OSNR penalty is below 1.4dB at 10^-3 bit error rate (BER) which has same as the decision directed single tap filter.