Method and apparatus for driving laser diode
AssigneeAdvantest Corporation
InventorToshiyuki Okayasu
Life of this patent
Estimating the term…
Abstract
A time measuring unit measures an extinction interval in a drive signal to produce a time signal −Vdt of a level which corresponds to the extinction interval. The time signal is superimposed upon a drive current as a reverse current with respect to a laser diode at the time the current through the laser diode LD rises, thereby rapidly reducing residual carriers in the laser diode to suppress the occurrence of a jitter at the initiation of the light emission.
Claims16
An apparatus for driving a laser diode, comprising:
- a laser diode;
- power supply means for supplying a driving power to the laser diode;
- switching means connected in series with the laser diode to control a drive current which passes through the laser diode in accordance with a drive signal which repeats an ON and an OFF interval to switch the laser diode between a light emission and an extinction;
- time measuring means for measuring an OFF interval of the drive signal and delivering a time signal having a level which corresponds to the interval;
- and
- current control means for controlling the drive current in accordance with a control signal which corresponds to the time signal such that the shorter the interval, the longer the rising of the drive current is retarded.
An apparatus for driving a laser diode comprising:
- a laser diode;
- power supply means for supplying a driving power to the laser diode;
- switching means connected in series with the laser diode to control a drive current which passes through the laser diode in accordance with a drive signal to switch the laser diode between a light emission and an extinction;
- and
- differential current generating means for generating a differential current from the drive signal and applying it as a reverse differential current to the laser diode during the extinction of the laser diode.
A method of driving a laser diode in which a drive current passing through a laser diode is turned on and off by switching means in accordance with a drive signal which repeats an ON and an OFF interval to switch the laser diode between a light emission and an extinction, comprising the steps of:
- (a) measuring an OFF interval in the drive signal to generate a time signal of a level which corresponds to the extinction interval;
- and
- (b) controlling the drive current on the basis of the time signal such that the shorter the interval measured, the longer the a rising of the drive current is retarded.
A method of driving a laser diode in which a drive current passing through a laser diode is turned on and off by switching means in accordance with a drive signal to switch the laser diode between a light emission and an extinction, comprising the steps of:
- (a) generating a differential current from the drive signal;
- and
- (b) superimposing the differential signal upon the drive current so that the differential current from the falling edge of the drive current is effective in reducing residual carriers.
Dependencies are inferred from the claim text.