Patent ID: 7711021
Filing Date: 2010-05-04
Classification: H01S

Abstract:
1. A driver circuit for a semiconductor laser diode, comprising: a filter circuit connected in parallel with the laser diode, the filter circuit including a resistor, a reversely biased varactor diode having a variable capacitance and connected in series with the resistor, and a capacitor with constant capacitance connected in series with the reversely biased varactor diode; a power supply; a signal generator to generate a signal for driving the laser diode, wherein the signal generator, the filter circuit and the laser diode are connected in parallel with respect to each other and are each connected in series with the power supply; and a controller for controlling a value of capacitance of the varactor diode by adjusting a bias voltage applied thereto to control a frequency response of the filter circuit, the controller being connected with a node between the varactor diode and the capacitor to be isolated from the power supply in a direct current mode by the capacitor, wherein the reversely biased varactor diode is controlled in junction capacitance thereof by the controller.