Ring laser gyro having ring resonator semiconductor lasers and driving method thereof

#1. Field of the Invention

#The present invention relates to a ring laser gyro that detects an angular velocity of a rotary motion by using a semiconductor ring laser, and more particularly to a ring laser gyro that is capable of detecting a direction of rotation.

#2. Related Background Art

#FIGS. 1A and 1B are diagrams showing a ring laser gyro in accordance with a first embodiment of the present invention;

#FIG. 2 is a diagram showing the ring laser gyro, a drive circuit and a signal processing circuit in accordance with the first embodiment of the present invention;

#FIG. 3 is a graph showing a frequency and an angular velocity of a beat signal of the ring laser gyro in accordance with the first embodiment of the present invention;

#Now, a description will be given in more detail of preferred embodiments of the present invention with reference to the accompanying drawings.

#(First Embodiment)

#FIG. 1A is a plan view showing an optical gyro in accordance with a first embodiment, and FIG. 1B is a cross-sectional view taken along a line 1B—1B of FIG. 1A. Reference numeral 10 denotes an optical gyro element according to the present invention, numerals 11 and 12 indicate ring resonator semiconductor laser elements, respectively, and numerals 13 and 14 indicate portions each of which changes a waveguide width disposed in a part of a waveguide (hereinafter referred to as “tapered portion”). In the ring resonator semiconductor laser element, there exist a counterclockwise circumferential mode indicated by reference numeral 15 and a clockwise circumferential mode indicated by reference numeral 16.