METHOD OF STABILISING LASER EMISSION FREQUENCY Russian patent published in 2012 - IPC H01S3/139 

FIELD: physics.

SUBSTANCE: emission power resonance is formed in a laser resonator, a signal which is proportional to the output emission power of the laser is measured and the laser resonator is modulated with a probe signal which is proportional to laser emission frequency fluctuations. The sign of the current resonance gradient of the emission power is determined from the signal which is proportional to the output emission power of the laser and said probe signal. At each tuning step, a signal for tuning the laser resonator is generated, which coincides with the sign of the current gradient on the extremum of the laser emission power resonance. The amplitude of the tuning signal at each tuning step is variable and proportional to the current value of the modulus of the asymmetry coefficient - the standardised third midpoint of the distribution density function of the signal of the laser output emission power. In order to generate the tuning signal, a cross-correlation function between the signal of the laser output emission power and the signal which is proportional to laser emission frequency fluctuation is determined. The signal which is proportional to laser emission frequency fluctuations is first passed through a tunable band-pass filter whose centre frequency is inversely proportional to the value of the time argument of the maximum of the found cross-correlation function.

EFFECT: high stability of laser emission frequency.

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