| 摘要 |
PURPOSE:To make linearity good to make it possible to use an optical transmission unit for a high frequency by improving the trouble of the response of the optical feedback methode, which is a defect conventionally, by negative feedback in the optical transmission unit using a semiconductor laser. CONSTITUTION:Input electric signals are applied to the base of outputting transistor 7 of a driving circuit, and are amplified by the collector earth system, and are applied to semiocnductor laser 2. After being coupled with avalanche photo diode 6 and being converted and amplified to a current, a part of the output light from semiconductor laser 2 is led to semiconductor laser 2 directly. A negative voltage for bias is applied to one side of photo diode 6 and can adjust the multiplication degree of photo diode 6. Then, the current from photo diode 6 is connected in the direction where the output current of transistor 7 is cancelled, so that the loop of semiconductor 2 and photo diode 6 may be a negative feedback loop. |
