Method of stabilizing the wavelength of lasers and a wavelength monitor
AssigneeAlcatel
InventorsDaniel Mousseaux, Franck Le Gall
Life of this patent
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Abstract
A method of stabilizing the wavelength of lasers comprising a control circuit is proposed, wherein the light of the laser passes through a splitter and the split light passes through a wavelength filter in a first branch, and the light of both branches is in each case received by a photodetector. The photodetector of the first branch can be operated with different gain factors. The wavelength filter has a free spectral region which is greater than the spacing between the individual wavelengths in a wavelength division multiplex.
Claims5
A method of stabilizing the wavelength of lasers (5) comprising a control circuit which regulates the wavelength of the laser, wherein the light of the laser passes through a splitter (3), and the split light passes through a non-tunable wavelength filter (4) in a first branch,
- the light of both branches is in each case received by a photodetector (P1, P2),
- one of the photodetectors is operated with at least two gain factors,
- the non-tunable wavelength filter (4) has a nearly linear region which is greater than the spacing between individual wavelengths in a wavelength division multiplex,
- the combined signals of the two photodetectors serve as an error signal for regulating the temperature of the laser, and
- said one photodetector is driven at different voltages to vary the gain of said one photodetector.
A wavelength monitor (1) for regulating the wavelength of a laser (5) comprising an optical input (2), a splitter (3), a non-tunable wavelength filter (4) in one branch, and two photodetectors (P1, P2), characterised in that
- one of the photodiodes can be operated with at least two gain factors,
- the wavelength filter (4) has a free spectral region which is greater than the spacing between the wavelengths in a wavelength division multiplex, and
- at least two voltage drivers are provided for varying the gain of said one photodiode.
Dependencies are inferred from the claim text.