Title :
Optically implemented DPSK and CPFSK systems: effect of post-detection filtering
Author_Institution :
TFL Telecommun. Res. Lab., Horsholm, Denmark
Abstract :
Results for the sensitivity of preamplifier differential phase-shift keying (DPSK) and continuous phase-shift keying (CPFSK) systems with electronic post-detection filtering are presented based on a rigorous model which is outlined. It takes into account amplifier and laser phase noise. The best sensitivities for a 10/sup -9/ error probability are 20 (DPSK) and 36 (CPFSK) received photons. It is found that the CPFSK system can tolerate significant phase noise by increasing the modulation index and the bandpass filter bandwidth. A linewidth of 5 times the bit-rate causes 4.3 dB penalty using polarization control and for a modulation index of 51. DPSK systems cannot tolerate linewidths larger than about 1% of the bit-rate.<>
Keywords :
frequency shift keying; optical links; optical modulation; phase shift keying; probability; random noise; sensitivity; spectral line breadth; CPFSK systems; DPSK; Er-doped fibre amplifiers; amplifier noise; bandpass filter bandwidth; continuous phase-shift keying; electronic post-detection filtering; error probability; laser phase noise; linewidth; modulation index; phase noise; polarization control; post-detection filtering; preamplifier differential phase-shift keying; sensitivity; Differential phase shift keying; Differential quadrature phase shift keying; Modulation; Optical filters; Optical noise; Optical sensors; Phase noise; Phase shift keying; Preamplifiers; Stimulated emission;
Journal_Title :
Photonics Technology Letters, IEEE
