| 摘要 |
PROBLEM TO BE SOLVED: To secure a required high frequency superimposition current at a DC source voltage of a high frequency superimposition circuit and to reduce a return light noise by constituting so as to apply a high frequency output to a semiconductor laser through an inductor. SOLUTION: A coil L4 is inserted between the connection point of capacitors C4, C5 and the semiconductor laser LD, and the high frequency output is applied to the semiconductor laser LD through this coil L4. Further, a stabilized DC current is supplied from a laser driving control voltage source to a coil L4 end side of a series circuit between the coil L4 and the semiconductor laser LD through the coil L3. By inserting the coil L4, an effect of static capacity incorporated in the equivalent circuit of the semiconductor laser LD is canceled by the inductivity of the coil L4, and impedance matching is improved. Then, the required high frequency superimposition current is secured by the low DC source voltage Vcc of the high frequency super-imposition circuit, and the return light noise is reduced, and low power consumption in a recording/reproducing device is realized. |
