The essence of OPSK modulation is to reduce the baud rate of the optical signal by half without reducing the line rate by washing four possible values on the phase of the optical field; this…

The essence of OPSK modulation is to reduce the baud rate of the optical signal by half without reducing the line rate by washing four possible values on the phase of the optical field; this multiplexing method can reduce the spectral bandwidth of the optical signal by half, making multi- wavelength ULH transmission with 50GHZ interval and 40G line rate possible.