| 摘要 |
PURPOSE:To vary the light quantity at a high speed by providing an analog A/O modulator for modulating a stabilized laser by an analog A/O control signal and generating optical modulation signal. CONSTITUTION:A laser light source 1 generates laser light (a). A laser light quantity control part 2 controls the laser light (a) by a light quantity command signal b-1, and generates stabilized laser light (c) from which the noise has been eliminated. A level switching circuit 3-1 generates an analog A/O control signal d-2 which has brought amplitude of a digital modulation signal d-1 to amplitude modulation by a level switching signal (e). An analog A/O modulator 4-1 modulates the stabilized laser light (c) by an analog A/O control signal d-2, and generates an optical modulation signal (f). In such a way, an analog type is used, and this modulator is allowed to have both a switching function for turning ON/OFF an optical signal, and a function for making a level in an ON state variable, by which the light quantity can be varied at a high speed. |
