Patent ID: 8693514

Claim:
A pulse generation method of a light emitting element, the method comprising the steps of: preparing a seed light source which includes a light emitting element outputting laser light; a driving current supply section supplying a driving current to the light emitting element; a modulator applying a modulation voltage for pulse modulation of the laser light to the seed light source according to a pulse modulation pattern of the modulation voltage for instructing a pulse-ON state and a pulse-Off state of the seed light source; and a modulation control section determining optimal modulation voltages for a predetermined pulse width, in both the pulse-ON state and the pulse-OFF state; monitoring the driving current supplied to the seed light source or output light power from the seed light source; setting, in response to change of the driving current value, the modulation voltages in both of the pulse-ON state and the pulse-OFF state which respectively correspond to the driving current in both pulse-ON state and the pulse-OFF state after the change of the driving current value so that a pulse width after the driving current value change falls within ±20% with reference to the predetermined pulse width the set modulation voltage in the pulse-ON state being different from the modulation voltage in the pulse-ON state which corresponds to the driving current in the pulse-ON state before the change of the driving current value, the set modulation voltage in the pulse-OFF state being different from the modulation voltage in the pulse-ON state which corresponds to the driving current in the pulse-ON state before the change of the driving current value; and making the modulation control section send information on the pulse modulation pattern to the modulator so that the modulation voltage in the pulse-ON state and the modulation voltage in the pulse-OFF state respsectively reaches the set values.