Abstract: In an optical transmitter, continuous wave light from a laser passes through a data modulator (DM) for non-return-to-zero (NRZ) encoding of a data stream and through a pulse modulator to add return-to-zero encoding to the modulated optical signal. A modulator controller monitors the output optical signal power, optimizes the bias setting for the DM and the PM, and optimizes the phase relationship between the pulse and data components of the modulated optical signal. For each optimization, a low amplitude and low frequency dither signal is injected at appropriate points in the modulator. A single photo detector and electrical receiver are used in a multiplexed fashion to monitor the optical output signal and derive separate feedback signals. Remaining control circuitry forces a null in a respective residual dither component in the optical output signal to maintain the desired bias level or phase alignment.

Abstract: An optical signal regeneration device having an interferometric structure with two arms. Each of the arms has a medium, the optical power output of which is variable with the optical power input. The first arm receives, through an input coupler, a continuous wave and the signal to be regenerated. The second arm receives through the input coupler, a continuous wave signal and a clock signal. A filter, centered on the continuous wave wavelength, receives the output signal of the interferometric structure through the coupler. The filter output signal constitutes the regenerated 3R signal.

Abstract: A high speed digital optical transmission system that improves data transmission performance in both linear and nonlinear system environments. The high speed optical transmission system includes a laser for generating a CW light beam, and a data modulator for modulating the CW light beam in response to an electrical NRZ data signal to generate a modulated NRZ optical signal with positive chirp. The bias point of the data modulator is obtained by increasing the bias offset relative to quadrature while maintaining the voltage corresponding to a 0 bit at a predetermined level. The bias point allows the data modulator to be operated so that the chirp of the modulated NRZ optical signal is positive for most of each bit time slot.

Abstract: In an optical transmitter, continuous wave light from a laser passes through a data modulator (DM) for non-return-to-zero (NRZ) encoding of a data stream and through a pulse modulator to add return-to-zero encoding to the modulated optical signal. A modulator controller monitors the output optical signal power, optimizes the bias setting for the DM and the PM, and optimizes the phase relationship between the pulse and data components of the modulated optical signal. For each optimization, a low amplitude and low frequency dither signal is injected at appropriate points in the modulator. A single photo detector and electrical receiver are used in a multiplexed fashion to monitor the optical output signal and derive separate feedback signals. Remaining control circuitry forces a null in a respective residual dither component in the optical output signal to maintain the desired bias level or phase alignment.

Abstract: An optical signal regeneration device comprises an interferometric structure having two arms (11, 12). Each of the arms (11, 12) comprises a medium the optical power output of which is variable with the optical power input. The first arm (11) receives, through input coupling means (13), a continuous wave and the signal to be regenerated. The second arm receives through input coupling means (13) the continuous wave and a clock signal. A filter 21, centered on the continuous wave wavelength, receives through coupling means (14), the output signal of the interferometric structure (10). The filter output signal constitutes the regenerated 3R signal.