Frequency pulling reduction in SBS laser

A method for reducing gain pulling in a stimulated Brillouin scattering (SBS) laser, the method comprising:

• generating at least one SBS wave from a pump light beam emitted by a pump laser coupled to an optical resonator;
• applying an intensity modulation to the pump light beam at a given wavelength;
• monitoring for gain pulling by measuring a first harmonic of a pump intensity at a pump transmission port;
• if the first harmonic is equal to zero, then a separation between a gain peak and an SBS resonance peak is zero, and there is no gain pulling;
• if the first harmonic is not equal to zero, applying a control technique comprising:
• adjusting a SBS frequency shift by tuning a temperature of the optical resonator;
• or
• adjusting a frequency of the pump laser through a laser locking offset.

A stimulated Brillouin scattering (SBS) laser gyroscope, comprising:

• a first pump laser device operative to emit an input clockwise (CW) pump beam at a first pump frequency along a first optical pathway;
• a first intensity modulator in optical communication with the first pump laser device along the first optical pathway, the first intensity modulator operative to modulate an intensity of the input CW pump beam and output an intensity modulated CW pump beam;
• a second pump laser device operative to emit an input counterclockwise (CCW) pump beam at a second pump frequency along a second optical pathway;
• a second intensity modulator in optical communication with the second pump laser device along the second optical pathway, the second intensity modulator operative to modulate an intensity of the input CCW pump beam and output an intensity modulated CCW pump beam;
• an input optical coupler in optical communication with the first and second intensity modulators and configured to receive the intensity modulated CW and CCW pump beams output from the first and second intensity modulators;
• an optical resonator optically coupled to the input optical coupler, the optical resonator configured to:
• receive the intensity modulated CW pump beam from the input optical coupler such that the intensity modulated CW pump beam travels in a CW direction in the optical resonator;
• and
• receive the intensity modulated CCW pump beam from the input optical coupler such that the intensity modulated CCW pump beam travels in a CCW direction in the optical resonator;
• wherein when an optical frequency of the intensity modulated CW pump beam matches a resonance frequency of the optical resonator, an optical power density within the optical resonator increases such that beyond a certain threshold power, the intensity modulated CW pump beam produces a first SBS gain spectrum and eventually generates a first SBS laser, wherein a first SBS wave travels in a CCW direction in the optical resonator;
• wherein when an optical frequency of the intensity modulated CCW pump beam matches the resonance frequency of the optical resonator, an optical power density within the optical resonator increases such that beyond a certain threshold power, the intensity modulated CCW pump beam produces a second SBS gain spectrum and eventually generates a second SBS laser, wherein a second SBS wave travels in a CW direction in the optical resonator;
• an output optical coupler optically coupled to the optical resonator, the output optical coupler configured to:
• receive and output the intensity modulated CW pump beam and the second SBS wave from the optical resonator in a first direction;
• receive and output the intensity modulated CCW pump beam and the first SBS wave from the optical resonator in an opposite second direction;
• a first control unit in optical communication with the output optical coupler, the first control unit configured to receive an output signal corresponding to the intensity modulated CW pump beam, the first control unit operative to eliminate or reduce a frequency gap between the second SBS gain peak and a SBS resonance peak;
• and
• a second control unit in optical communication with the output optical coupler, the second control unit configured to receive an output signal corresponding to the intensity modulated CCW pump beam, the second control unit operative to eliminate or reduce a frequency gap between the first SBS gain peak and the SBS resonance peak.