Abstract: In accordance with the invention, a wavelength stable optical source comprises at least one adjustable wavelength optical source, a multipath Mach-Zehnder interferometer (MMZI) for receiving a signal from the adjustable source and providing a primary output and one or more secondary outputs, and a feedback arrangement responsive to the outputs for adjusting the wavelength source. Photodetectors coupled to the primary output and one or more of the secondary outputs provide feedback information for maintaining wavelength stability.

Abstract: The present invention provides N×N non-blocking switch modules using MMI-based switch elements. The arrangement requires a minimum of control elements to effect switching and uses no crossings of the signal waveguides. The switch control settings may be determined by following a simple and transparent algorithm for the setup procedure. Very high-order switch fabrics comprising a variety of the taught nonblocking N×N switch modules are envisaged. Determination of the appropriate values for ‘N’ is a practical consideration which trades-off the performance of the individual switch modules with the complexity required of the associated module interconnection fabric. The spatial switch fabrics that may by built from the non-blocking MMI-based switch arrangements may be combined with both wavelength-division switches and time-division switches to form any combination of higher order space-wavelength-time switch.