Abstract: The invention relates to the field of laser technology and is intended for the provision of stable generation of ultrashort laser pulses. The proposed method and device are implemented in a unidirectional polarizing resonator, at a given level of optical amplification in the active fiber section of an amplifier. The resonator contains a non-linear optical element having two loops with passive thermal compensation by means of special placing together of the asymmetric sections of birefringent fiber. Both loops are thermostatically controlled. The selection and fixing of the temperatures of these two loops, at a given level of optical amplification in the optical amplifier, further ensures the optimal ratio of the linear and non-linear parts of the phase difference between the polarization components of the optical wave at the NOE output, by which there is stable ultrashort pulsing autogeneration with self-excitation at start up each time the laser is switched on.

Abstract: The disclosed method and apparatus for stabilizing a mode-locked regime of a fiber ring oscillator based on a NPR include tapping a portion of light, which has a broad spectral bandwidth, from a fiber ring resonator into at least first and second control channels. The control channels are configured to guide respective first and second fractions of the tapped portion. One of the control channels is provided with a bandpass filter operative to extract a region from the broad spectral bandwidth. The fractions with respective full spectral bandwidth and region thereof are then evaluated in a central processing unit which is operable to generate a control signal if a predetermined criterion is not met. The control signal is received by one or more polarization controller units operative to dynamically modulate a state of polarization of light in the fiber ring resonator until the evaluation meets the predetermined criterion.