Laser diode driving circuit and laser diode driving method

Abstract

This invention provides a laser diode driving circuit that stabilizes the pulse intensity of laser light and reduces jitter. [Solution] A laser diode driving circuit is provided, comprising: a pulse-modulated bias application circuit that applies a pulse-modulated bias to the laser diode to cause the laser diode to pulse-oscillate; a reverse bias current application circuit that applies a reverse bias to the laser diode to temporarily make the gain of the laser diode negative during pulse oscillation; and a clock source that synchronizes the pulse-modulated bias and the reverse bias.

Claims

1. A pulse-modulated bias application circuit that applies a pulse-modulated bias to a laser diode to cause the laser diode to oscillate in pulses, A reverse bias current application circuit that applies a reverse bias to the laser diode to temporarily make the gain of the laser diode negative during the pulse oscillation, A clock source that synchronizes the pulse-modulated bias and the reverse bias, A laser diode drive circuit equipped with the following features.

2. The laser diode driving circuit according to claim 1, further comprising a sine wave generation circuit for generating a sine wave bias used to generate the aforementioned reverse bias.

3. Furthermore, the laser diode driving circuit according to claim 2 further comprises a DC bias generation circuit that generates a DC bias to be applied in order to adjust the bias.

4. The laser diode driving circuit according to claim 3, wherein the amplitude of the positive side of the sine wave is 50% or more of the oscillation threshold of the laser diode when modulated with only a sine wave.

5. The laser diode driving circuit according to claim 2, further comprising a merger with different degrees of coupling for merging the pulse-modulated bias and the sinusoidal bias.

6. The laser diode driving circuit according to claim 5, wherein the merger is a directional coupler or a resistive coupler.

7. The system includes a frequency-selective filter into which the pulse-modulated bias and the sinusoidal bias merge, The laser diode driving circuit according to claim 2, wherein the frequency-selective filter selects the sinusoidal bias as the fundamental wave and the pulse-modulated bias as the harmonic.

8. The laser diode driving circuit according to claim 2, further comprising a phase adjustment circuit for controlling the phase relationship between the pulse-modulated bias and the sinusoidal bias.

9. The laser diode driving circuit according to claim 2, wherein the output from the laser diode is passed through a narrow-band bandpass filter that narrows the pulse waveform.

10. A pulse-modulated bias is applied to the laser diode to cause the laser diode to oscillate in pulses. A reverse bias is applied to the laser diode to temporarily make the gain of the laser diode negative during the pulse oscillation. A laser diode driving method that synchronizes the pulse-modulated bias and the reverse bias.

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