| 摘要 |
PURPOSE:To stabilize oscillation frequency and oscillation output of a semiconductor laser, by providing a control section for controlling a current supplying source based on light received by a light-receiving section so as to allow the semiconductor laser to have constant oscillation output and to stabilize the oscillation frequency. CONSTITUTION:A comparator circuit 1 compares an operating temperature changing voltage ET as output of detection of an operating temperature with a correcting reference voltage ES2 and outputs a signal indicating a difference between them. A transistor 2 is controlled by this differential output, and a Peltier-effect-type element 3 is thereby energized and controlled such that the operating temperature TT attains an equilibrium state. In order that an equilibrium temperature Te coincides with a setted temperature TS, the difference between a reference voltage ES1 and a voltage corresponding to the equilibrium temperature Ee must be zero, that is the condition of EC=EC'+EC'' must be met. In the formula, EC' means a correcting voltage required for correcting a difference between the operating temperature TT and the setted temperature TS and EC'' means a differential correcting voltage for correcting TT and TS. By adding these correcting voltages EC' and EC'' to provide a control voltage EC, the equilibrium temperature Te can be made concide with the setted temperature TS. In this manner, a oscillation frequency and output of the semiconductor laser can be stabilized. |
