| 摘要 |
PROBLEM TO BE SOLVED: To provide a laser driving circuit achieving a high-speed burst response and a power reduction at laser extinction. SOLUTION: The laser driving circuit includes: a modulation circuit 10 for supplying a modulation current to a laser diode LD according to input burst data; a bias circuit 20 for applying a bias current to the laser diode LD; and an APC circuit 30 for controlling the modulation current and the bias current so as to obtain a desired emission intensity and a desired extinction ratio in the laser diode LD. When a transmission enable signal TX_EN is on, the laser diode LD is burst-driven according to the input burst data, and when the transmission enable signal TX_EN is off, the laser diode LD is extinguished. The modulation circuit 10 includes a modulation current cutoff circuit 15 for cutting off the modulation current when the transmission enable signal TX_EN is off, and a bias circuit 20 includes a bias current cutoff circuit 21 for cutting off the bias current when the transmission enable signal TX_EN is off. COPYRIGHT: (C)2011,JPO&INPIT
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