| 摘要 |
PURPOSE:To stabilize the laser oscillation wavelength by superposing a signal, which is obtained by making an outgoing light wavelength switching signal pass through a low pass filter, on the outgoing light wavelength switching signal and controlling the injected current of a semiconductor laser in accordance with this superposed signal. CONSTITUTION:A part of outgoing light of a distributed Bragg-reflector three-electrode semiconductor laser DBRLD 1 as the control object is branched by an optical branching device 2 and is made incident on a Fabry-Perot etalon FP 3, and the wavelength change of the semiconductor laser is converted into the outgoing light power of the FP 3, and it is converted into an electric signal by a photodetector 4. This output is compared with a voltage Vref, which is obtained by converting the output light power of the FP 3 corresponding to the control target wavelength into an electric signal, by a differential amplifier 5, and the output is multiplied by a proportional constant in an amplifier 6, and the result is superposed on the switching waveform, and it is fed back to the phase area and the DR area of the DBRLD 1. The signal obtained by making the switching pattern pass a low pass filter 7 is applied as the injected current of the DBRLD 1 besides two these signals. The output of the filter 7 is so set that the temperature change of the pattern is cancelled. |
