High capacity wavelength division multiplexer

Claim 1

A high-capacity wavelength division multiplexer, comprising: an optical dispersive device; means for directing multiple light beams of different wavelengths onto the dispersive device at wavelength-dependent angles of incidence, wherein the dispersive device provides a composite output beam including multiple beams at the different wavelengths propagating along a substantially common path; a tunable optical bandpass filter positioned to receive at least a portion of the composite beam; means for tuning the optical bandpass filter to successive settings corresponding to the different wavelengths of the multiple light beams; a sensor, positioned to provide a measure of beam angle difference from the common light path for successive beams emitted from the tunable optical bandpass filter, the measure of beam angle difference being indicative of wavelength error; and means for generating a light source control signal from each measure of beam angle difference provided by the sensor, for wavelength correction.

Claim 7

A method for wavelength division multiplexing a large number of laser light beams, the method comprising the steps of: generating multiple laser beams from separate controllable laser sources; launching the multiple laser beams into separate optical fibers; emitting multiple laser beams from the separate optical fibers arrayed in wavelength sequence; collimating the emitted laser beams and directing the collimated beams onto a dispersive grating, at angles of incidence that are wavelength dependent; reflecting light from the grating in a composite beam propagating over a substantially common return path; splitting off a sample beam from the composite beam; passing the sample beam through a tunable etalon for narrow bandpass filtering; controlling the tunable etalon to provide a succession of output beams corresponding in wavelength to the wavelengths of a succession of the laser sources operating at different wavelengths; measuring angular difference in the succession of etalon output beams, wherein angular difference from a nominal angle is indicative of wavelength error; and controlling the wavelengths of the laser sources in accordance with the measured angular difference for each etalon output beam, whereby the source laser wavelengths are controlled to provide reliable multiplexing of the laser beams.

Claim 8

A method for wavelength division multiplexing a large number of laser light beams, the method comprising the steps of: generating multiple laser beams from separate controllable laser sources; launching the multiple laser beams into separate optical fibers; emitting multiple laser beams from the separate optical fibers arrayed in wavelength sequence; collimating the emitted laser beams and directing the collimated beams onto a dispersive grating, at angles of incidence that are wavelength dependent; reflecting light from the grating in a composite beam propagating over a substantially common return path; splitting off a sample beam from the composite beam; passing the sample beam through a tunable etalon for narrow bandpass filtering; controlling the tunable etalon to provide a succession of output beams corresponding in wavelength to the wavelengths of a succession of the laser sources operating at different wavelengths; measuring angular difference in the succession of etalon output beams, wherein angular difference from a nominal angle is indicative of wavelength error; and controlling the wavelengths of the laser sources in accordance with the measured angular difference for each etalon output beam, whereby the source laser wavelengths are controlled to provide reliable multiplexing of the laser beams.