Societe Anonyme De Telecommunications

Sat (societe Anonyme De Telecommunications)

Sat Corporation

Michel M Ouhayoun

Alain Robert

Thierry, R Midavaine

Thierry R Midavaine

A coherent optical detector has increased sensitivity for detecting a coherent optical signal by applying the coherent optical signal to be detected to a solid non linear medium pumped by two optical signals of opposite directions and coming from an auxiliary laser. The signal to be detected gives rise to an amplified signal applied with an auxiliary optical signal from the auxiliary laser, to a detector for causing these two optical signals to beat and detecting the beat and so the signal to be detected.

Coherent detection with increased sensitivity using four-wave

A frequency stabilized pulsed laser system useful for heterodynes telemetry comprises an amplifying medium (21), between a mirror (27) and a four wave mixing phase conjugate mirror (30). The non linear medium of mirror (30) is a part of the laser medium (21), because of the presence of a lens (31). The mirror (30) is pumped by the direct beam of a continuous laser (29) and the reflected beam from the mirror (27). The light emission of the laser exits through an optical isolator (28).

Frequency stabilized pulsed laser system

A device is provided for stabilizing the frequency of an RF excitation laser, comprising a means for matching the impedance of the cavity of the laser with that at the output of the excitation generator. The matching means are connected through a line to a circulator which is connected to the generator and to an RF diode. A synchronous detector is connected to the outputs of the diode and of an oscillator. The output of the detector is connected through an integrator to a piezoelectric ceramic supporting one of the mirrors of the cavity of the laser, modulated by the oscillator. The phase shift between the signal reflected by the cavity and the signal of the oscillator and the amplitude of the former allow the cavity to be stabilized in frequency.

Device for frequency stabilizing an RF excitation laser

A switching laser comprising, in a cavity, a cell of an amplification gas and a cell of an absorption gas, means for exciting said amplification gas and means for exciting said absorption gas. Said means for exciting the absorption cell comprise a radio frequency AC voltage source pulsed at a certain rate. The laser is namely used for infrared detection.

Switching laser

The generator comprises an envelope and two mirrors defining a resonant cavity, in which is maintained a monolithic wave-guide with a capillary. The capillary is formed in a thinned portion of the guide. Two electrodes extend over the thinned portion of the guide. The capillary is circular in cross section, this being obtained by drilling or extrusion of a cylindrical bar made of dielectric material. The circulation of the laser gas is excellent and the laser plasma uniform. The generator has multiple applications, for example in the medical field.

Growing community of inventors

Paris, France

Michel M Ouhayoun