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US 4,700,150 AGranted
External laser frequency stabilizer
AssigneeStanford University
InventorsJohn L. Hall, Theodor W. Hansch
Life of this patent
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Abstract
An external laser frequency stabilizer combines an acousto-optic frequency shifter and a fast electro-optic phase modulator. A compensating electronic delay line in a crossover network provides a near-ideal transducer response while keeping the voltage across the electro-optic crystal away from the amplifier limits.
Claims5
A frequency transducer for controlling or modulating the frequency of a light radiation system comprising:
- a source of radiation having a predetermined frequency;
- an electro-optic phase modulator for receiving said radiation and for changing the phase of said radiation in proportion to an applied error voltage;
- an acousto-optic modulator coupled to said electro-optic modulator for shifting the frequency of the output signal of said electro-optic modulator;
- a signal source for providing an error voltage representing undesirable fluctuations in the frequency of said light radiation;
- a first channel including a fast integrator coupled between said signal source and the input circuit of said electro-optic modulator;
- a second channel including a voltage controlled oscillator coupled between said signal source and said acousto-optic modulator;
- and
- a network including an electronic delay circuit coupled between said first and second channels for matching the delay of the acousto-optic modulator.
5 more elements
Dependencies are inferred from the claim text.