Transmission Analysis of 112 Gbps Dual Polarization QPSK /16QAM Using Coherent Receiver with Digital Signal Processing

This paper demonstrates the performance of 112 Gbps Dual polarization quadrature-phase shift-keying (DP QPSK) and Dual polarization quadrature amplitude modulation (DP 16 QAM) multilevel modulation formats in terms of signal to noise ratio (SNR) for different fiber lengths, polarizing angle and optical signal to noise (OSNR) tolerance. Also mitigated channel impairments by using digital signal processing (DSP) for dispersion compensation, polarization demultiplexing, frequency and carrier phase estimation in coherent receiver. It was observed that DP 16 QAM shows more SNR as compared to DP QPSK for all fiber lengths and system performance degrades when polarizing angle is increased from 0° to 20° due to polarization mismatch in transmitter. Also for particular BER of 10^-3, DP QPSK shows 4 dBm more OSNR tolerance than DP 16 QAM and received constellations after DSP are ideal which shows the mitigated channel impairments.