OPTICAL LENGTH CONTROL CIRCUIT FOR RING LASER GYRO, AND RING LASER GYRO

PROBLEM TO BE SOLVED: To prevent any control from being performed at any top part of high-order modes in laser oscillations. SOLUTION: An optical length control circuit includes; a carrier generating circuit 21; a multiplier 24 for multiplying a carrier by a detection output of a laser light intensity which is detected by a photodiode 22; an integrator 25 for integrating outputs of the multiplier 24; a control means 30 for output of a control output; a multiplier 41 for multiplying the carrier by the control output; and an adder 26 for adding an output of the multiplier 41 to an output of the integrator 25. The control means 30 includes; a first reference voltage generating circuit 31; a subtractor 33 for subtracting a first reference voltage from the detection output of the laser light intensity; an inverting type integrator 34 for integrating outputs of the subtractor 33; a second reference voltage generating circuit 32; and an adder 35 which adds an output of the integrator 34 to a second reference voltage, thereby generating the control output. A mirror transducer 15 which controls the optical length, is driven by the output of the adder 26. COPYRIGHT: (C)2010,JPO&INPIT