An all-optical regenerating circuit including a wavelength converter based on a Mach-Zehnder interferometer. The input signal is amplified and the interferometer adjusted to place the input signal across an entire monotonic portion of a sinusoidal transfer function to the wavelength-converted output signal. Retiming is effected by wavelength converters including pulsed laser sources of the output wavelength. A multi-wavelength regenerator may be integrated on a chip including two arrayed waveguides and an array of tunable lasers on parallel waveguides therebetween.