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Abstract

A wavelength locker (10) and system (70) for providing wavelength-locked multi-channels signals by using gas tuning. A number of radiation sources (72) provide beams of radiation at wavelengths separated by a predetermined spacing. One or more wavelength lockers (10) produce equally-spaced spectral lines (4) which are tunable in comparison to a wavelength reference, which is preferably the ITU grid (2). The wavelength locker (10) includes one or more etalons (12) which includes a gas-tunable medium (19) having a variable optical index of refraction. The etalons (12) are tuned by varying the pressure or composition of the gas-tunable medium(19) until the spectral lines (4) of the etalon (12) align with the ITU grid (4). The gas properties are then fixed by at least temporarily sealing the etalon (12). The etalons (12) may either be transmissive etalons (31), or reflective etalons (29). In a multi-channel system (70), beam splitters (76) divert a portion of the beams of radiation (48) into the wavelength lockers (10). Detectors (82) then receive the spectral line output (4) of the wavelength lockers (10) and detects shifts in wavelength of the spectral line output (4) to generates control signals (90). The wavelength of each of the radiation sources (72) is then adjusted in response to the control signals (90). The output (92) of the detector (84) may also be normalized in order to isolate the variations which are attributable to shift in wavelength.

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