Analysis of signal voltage in a semiconductor ring laser gyro

It is expected that a semiconductor ring laser is useful as a gyro because of its tiny size. Here, we propose to use as signals voltage changes in a semiconductor ring laser corresponding to rotation. These changes in the voltage during rotation are caused by an interference of clockwise and counterclockwise laser beams inside the ring cavity. In this paper, these signal voltages are analyzed for the first time by using rate equations, It is shown that the signal voltages saturate with an increase in the injection current into a semiconductor ring laser if gain saturation is neglected. When gain saturation is considered, there exists an optimum injection current to obtain a signal voltage as large as possible. To confirm validity of this analysis, a signal voltage below laser threshold is compared with that of a semiconductor optical amplifier, and good agreement is obtained.