Tesa Brown & Sharpe Sa

Observatoire Cantonal De Neuchatel

Alain Jornod

Pierre Thomann

Alex Bezinge

Christophe Moser

The laser diode (11) of the electro-optical device (10) is frequency-controlled with the aid of a control module (40) comprising a rubidium cell (41) and an optical sensor (42), as well as a further module (43) for controlling the injection current and/or the temperature of the laser diode. A controlling light beam (18) is conveyed by means of a multi-mode optical fiber (14) to the rubidium cell. The optical sensor measures the intensity of the light beam transmitted by the rubidium cell and supplies a signal used by the further module for regulating the injection current and/or the temperature of the laser diode so as to stabilize the frequency of the light (16) emitted. The optical fiber is coupled to the laser module in such a way as to collect part of the light (16, 21) emitted by the front face of the laser diode and reflected by a lens (12) in front of the laser diode. The diode-lens assembly is heat controlled. Feedback in the laser diode and the power supplied to the laser diode are reduced, and the control device is simplified. The device finds application particularly in interferometry, atomic frequency oscillators, spectroscopy, and fiber optics data transmission.

Electro-optical device comprising a controlled laser diode

The atomic frequency oscillator comprises a resonance cell (41) placed in a microwave resonator (53) surrounded by an electromagnetic shield (58). A laser module (10) emits a light beam which reaches the resonance cell and is used for optically pumping rubidium into the resonance cell. The light beam is conducted from the laser module to the resonance cell by an optical fiber (14) passing through the electromagnetic shield. The optical path traveled by the light beam does not include any beamsplitter. At least one controller uses the light beam conducted by the optical fiber for controlling the injection current and/or the temperature of the laser diode so as to stabilize the light emission frequency. The resonance cell serves both as resonance cell for controlling an oscillator (54) generating via a frequency multiplier (55) the signal for exciting the microwave resonator and as cell for controlling the laser diode (11).

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Colombier, Switzerland

Alain Jornod