Patent ID: 7970032

Claim:
A device for reducing a phase noise of a laser signal from a laser source, the device comprising: a first current generator for supplying a main driving current to the laser source for producing the laser signal; a phase noise detector responsive to the laser signal for generating a phase error signal; and a second current generator responsive to the phase error signal for generating a compensation current added to the main driving current supplied to the laser source for generating a phase-adjusted laser signal; wherein: the phase noise detector and the second current generator form a phase stabilization loop for reducing the phase noise of the laser signal; the phase noise detector comprises a wavelength drifting detector including (a) a wavelength discrimination filter supplied with the laser signal; the wavelength discrimination filter being so configured as to reflect a portion of the laser signal and to transmit a portion of the laser signal; (b) a first photodetector so connected to the wavelength discrimination filter as to measure the transmitted portion of the laser signal; and (c) a second photodetector so connected to the wavelength discrimination filter as to measure the reflected portion of the laser signal; wherein the ratio of the measured transmitted and reflected laser signal portions is laser wavelength dependent and is usable for detecting wavelength drifting of the laser signal; and the wavelength discrimination filter comprises a Fabry-Perot filter housed in a groove made in a solid metal body and the groove comprises means for preventing tension from being exerted on the Fabry-Perot filter; the size of the body being such that low frequency vibrations are not effectively transferred to the filter.