OPTICAL SIGNAL TRANSMISSION

摘要

An optical signal transmission apparatus for transmitting a plurality of dat a signals (data-1 to data-n) comprises: a plurality of input means (1) for receiving a respective one of the data signals (data-1) and delivering the respective data signal with a controlled phase and at a controlled data rate ; optical carrier generation means (4) for generating a plurality of optical carrier signals having different wavelengths (.lambda.1 to .lambda.2); a plurality of first modulation means (3) each being for modulating a respecti ve one of the optical carriers with a respective data signal to provide a first - modulated optical carrier signal; and an optical signal-routing device (15) having a plurality of input ports (15a to 15n), each port being for receivin g a respective one of the first-modulated optical carrier signals and deliveri ng it to the output port of the device. The apparatus further comprises further modulation means (13, 14) for further modulating each of the first-modulated optical carrier signals in dependence upon a clock (9) to provide a pluralit y of further-modulated optical carrier signals; and a feedback arrangement (17 , 16, 15, 8), including the optical signal-routing device (15), for feeding ba ck a proportion of each of the further-modulated optical carrier signals to a respective input means (1b) for controlling the phase and rates at which the input means delivers the data signal to the first modulation means in dependence upon the further modulation to thereby synchronize each input dat a signal to the clock. The optical signal-routing device delivers each of the further-modulated signals applied to its output to a respective input along a path which is dependent upon the wavelength of the signal.