Performance of a 10.709 Gb/s DPSK signal generated using a FIR filter and a DBR laser

The generation of a 10.709 Gb/s differential-phase-shift keying (DPSK) signal is demonstrated using a 2-tap finite impulse response (FIR) filter and a wavelength tunable directly modulated distributed Bragg reflector (DBR) laser. The taps of the FIR filter are set to [1, -1] enabling the generation of a bipolar drive signal with a full width at half maximum of 90 ps and a square-like pulse shape. The combined use of the FIR filter with the DBR laser allows for a compact DPSK transmitter. The quality of the DPSK signal is assessed using both noncoherent detection and coherent detection with digital signal processing. Transmission over a passive link consisting of 102 km of single mode fiber (SMF) is achieved using coherent detection and electronic dispersion post-compensation, with a received optical power (ROP) of -44.6 dBm at a bit error ratio (BER) of 3.8×10^-3 and a 50 dB loss margin. Using noncoherent detection and no dispersion compensation, the same transmission distance is achieved with a ROP of -18 dBm at a BER of 3.8×10^-3 and a 23 dB loss margin.