This paper presents the generation and the performance evaluation of an optical quadrature minimum shift keying (QMSK). The performance of our optical QMSK modulated system is evaluated and compared with those of traditional phase shift keying (PSK) and minimum shift keying (MSK) modulated systems, via simulation, in terms of receiver sensitivity, dispersion tolerance and self-phase modulation (SPM) penalty. The proposed scheme shows that the QMSK format offers a few transmission advantages comparing with than that of the other traditional modulation formats under SPM penalty.
This paper proposes an optical continuous-phase frequency shift keying (CPFSK) modulation scheme with an arbitrary modulation index. Simulations on the performances of CPFSK and differential phase shift keying (DPSK) show that CPFSK of modulation index is 2/3 performs best on receiver sensitivity, dispersion penalty and nonlinearity in the balanced receiving system of 40G.