Patent ID: 7701989
Filing Date: 2010-04-20
Classification: H01S

Abstract:
1. A laser diode driving apparatus comprising an oscillator for generating a high-frequency signal; an amplifier for receiving said high-frequency signal; current mirror circuits for receiving the output of said amplifier and driving respective multiple laser diodes; a DC current supply source for supplying a DC current to said current mirror circuits; a high-frequency superimposed current amplitude setting circuit for changing the amplitude of said amplifier so as to be suited for the selected current mirror circuit; and a controller for controlling said high-frequency superimposed current amplitude setting circuit, wherein said laser diode is driven using a current obtained by superimposing said high-frequency signal on said DC current; said high-frequency superimposed current amplitude setting circuit is provided with a D/A converter that outputs a current for changing the amplitude of said amplifier, and the output current of said D/A converter is changed so as to be suited for said laser diode, and the amplitude signal from said amplifier is superimposed on said DC current supplied from said DC current supply source in said current mirror circuit to generate a high-frequency superimposed current, and the selected laser diode is driven using the generated high-frequency superimposed current.