Stimulated brillouin ring laser gyroscope with optical frequency offset of counterpropagating pump laser signals

A ring laser gyroscope comprising:

• (a) a disk optical resonator (i) characterized by a free spectral range νFSR, a finesse F, and a Brillouin shift frequency νB, and (ii) arranged so that corresponding optical frequencies of at least one pair of resonant optical modes supported by the disk optical resonator differ by about νB;
• (b) a pump laser source that is arranged so as to (i) produce a first pump optical signal characterized by a first pump optical frequency νP1 and launch at least a portion thereof to propagate around the disk optical resonator in a forward direction, and (ii) produce a second pump optical signal characterized by a second pump optical frequency νP2 and launch at least a portion thereof to propagate around the disk optical resonator in a backward direction, wherein νP1 and νP2 are separated by a pump frequency offset ΔνP that is between about 0.0010·νFSR/F and about 10.·νFSR/F, and either νP2=νP1+ΔνP or νP2=νP1−ΔνP;
• (c) a frequency-locking mechanism coupling the pump laser source and the disk optical resonator and arranged so as to control the first pump optical frequency νP1, the second pump optical frequency νP2, or a laser optical frequency νP0 to maintain resonant propagation around the disk optical resonator of at least a portion of the first pump optical signal, at least a portion of the second pump optical signal, or at least a portion of a laser output optical signal characterized by the laser optical frequency νP0;
• and
• (d) a photodetector arranged so as to (i) receive a first stimulated Brillouin laser output optical signal, resulting from pumping by the first pump optical signal, that resonantly propagates around the disk optical resonator in the backward direction and is characterized by a first Brillouin laser frequency νL1 that is about equal to νP1−νB, (ii) receive second stimulated Brillouin laser output optical signal, resulting from pumping by the second pump optical signal, that resonantly propagates around the disk optical resonator in the forward direction and is characterized by a second Brillouin laser frequency νL2 that is about equal to νP2−νB, and (iii) produce from the received laser output optical signals an electrical output signal at a beat frequency ΔνL=|νL1−νL2| with 0<ΔνL<ΔνP.