| 摘要 |
PURPOSE:To provide an optical memory device which has the circuit simplified and has a high reliability by resolving the problem that a semiconductor laser monitor circuit of the optical memory device is complicated because of a need of two monitor circuits for monitor of the current flowing to a semiconductor laser itself and for monitor of reflected light of light emitted from the semiconductor laser and the problem that the reliability of the monitor circuit is reduced because of an occasional failure of proportion between the light emission level of the semiconductor laser and the operation current. CONSTITUTION:The optical memory device uses a voltage drop detecting circuit 102 and detects the voltage drop of a semiconductor laser drive circuit 101 to detect the operation current flowing to the semiconductor laser and compares this detection output with a reference signal 115 to monitor the operation state of the semiconductor laser. |
