| 摘要 |
PURPOSE:To enhance the degree of stabilization for optical output by detecting the fluctuations in the temperature of a laser diode (LD) device from its optical output changes and maintaining the temperature of said LD device constantly. CONSTITUTION:The optical output of an LD device 11 is couples with fiber 8 and transmitted to a transmission passage, but a part of the optical output enters a PIN diode 13 where it is taken out as the output of an electric monitor. The output of this monitor is superposed by a previous low frequency signal. This low frequency signal is selected by the subsequent band pass filter 5 and enters a control circuit 6. The low frequency signal in the control circuit 6 controls the control current to a Pelitier device 12. The Pelitier device 12 converts the control current into electric heat, thereby controlling the temperature of the LD device constantly. This construction makes it possible to enhance the degree of stabilization for the optical output. |
