Simple asymmetric optical DQPSK modulation and demodulation scheme

In this paper, an asymmetric optical DQPSK (A-DQPSK) modulation and demodulation scheme is proposed and demonstrated by simulation. This scheme features a simple pre-coding algorithm, simultaneous 2-digital binary signal demodulation, simplicity and low cost devices. By increasing the input power by 6%, the BER degradation of the A-DQPSK system can be eliminated. The low device cost and algorithm simplicity can make it a promising candidate in the next generation access network such as passive optical network (PON).