OPTICAL COMMUNICATION USING SUPER-NYQUIST SIGNALS

摘要

An optical transmitter multiplexes multiple optical channels for transmission over an optical communication medium. The spectrum of modulated signal in each optical channel is lowpass filtered in the electrical (digital) domain at half the channel baud rate such that super Nyquist signal multiplexing can be achieved in the optical domain without having to perform optical filtering. An optical coupler may be used to multiplex the multiple optical channels.

主权项

1. An optical communication method, comprising:
for a first optical channel in a plurality of optical channels having an equal baud rate:
mapping data using a quadrature phase shift keying (QPSK) constellation into a modulated signal;upsampling the modulated signal, thereby generating an upsampled signal;filtering the upsampled signal using a digital super-Nyquist lowpass filter having a cutoff frequency that is less than or equal to half of the baud rate, thereby generating a bandlimited modulated digital signal; andconverting the bandlimited modulated digital signal into a first optical analog signal; and optically multiplexing the first optical analog signal of the first optical channel with a second optical analog signal of a second optical channel from the plurality of optical channels to generate an optical output signal.