Laser diode driver circuit techniques

Patent metadata

Field	Value
Publication number	US-11075502-B2
Application number	US-201916555506-A
Country	US
Kind code	B2
Filing date	Aug 29, 2019
Priority date	Aug 29, 2019
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

Techniques to achieve higher power/shorter pulses with a laser diode. By initially applying a static reverse bias across the laser diode, the laser diode can turn on at a larger inductor current. When the laser diode is initially reverse biased, depletion charge and diffusion charge can be populated before the laser diode will lase. This causes the laser diode to initially turn on at a larger inductor current, which will reduce the rise time, thereby achieving higher power/shorter pulses.

First claim

The claimed invention is:

1. A diode driver circuit comprising:
a laser diode having an anode and a cathode, the laser diode to receive a pulse of current;
a power supply to couple with the cathode of the laser diode, the power supply configured to apply a static reverse bias across the laser diode to decrease the current through the laser diode after firing the laser diode; and
at least one electronic switch configured to control a forward current through the laser diode.

2. The diode driver circuit of claim 1 , wherein the power supply is adjustable, and wherein the adjustable power supply is configured to change a pulse width of the current through the laser diode.

3. The diode driver circuit of claim 1 , further comprising:
a capacitor coupled to the laser diode.

4. The diode driver circuit of claim 3 , coupled in parallel with another diode driver circuit, wherein the power supply is shared by the two diode driver circuits.

5. The diode driver circuit of claim 3 ; further comprising:
a diode coupled to the capacitor and an anode of the laser diode, wherein the power supply is coupled to the cathode of the laser diode and the anode of the diode.

6. The diode driver circuit of claim 1 , further comprising:
a charging circuit path including an inductive element and the at least one electronic switch.

7. The diode driver circuit of claim 1 , wherein the at least one electronic switch includes a first electronic switch and a second electronic switch, the diode driver circuit further comprising:
a charging circuit path including an inductive element and the first and second electronic switches.

8. The diode driver circuit of claim 1 , wherein the at least one electronic switch includes a first electronic switch and a second s electronic witch coupled in series, and wherein a terminal of the laser diode is coupled to a node between the first electronic switch and the second electronic switch.

9. The diode driver circuit of claim 1 , wherein the at least one electronic switch includes a first electronic switch, the diode driver circuit further comprising:
a diode, wherein the first electronic switch and the diode are coupled in series, and
wherein a terminal of the laser diode is coupled to a node between the first electronic switch and the diode.

10. A method of operating a laser diode, the method comprising:
coupling a voltage source to a cathode of the laser diode;
applying a pulse of current through the laser diode;
applying a static reverse bias voltage across the laser diode using the voltage source to decrease the current after firing the laser diode; and
adjusting the bias voltage to change a pulse width of the current.

11. The method of claim 10 , further comprising:
coupling a capacitor to the laser diode.

12. The method of claim 11 , further comprising:
adjusting a capacitance of the capacitor to adjust one or both of a charging voltage of the laser diode and a discharging voltage of the laser diode.

13. The method of claim 10 , wherein applying a current pulse through the laser diode includes:
during a charging phase, controlling a first electronic switch to turn ON and charge an inductive element, and during a firing phase, controlling the first electronic switch to turn OFF to discharge the inductive element and apply the current pulse through the laser diode.

14. The method of claim 10 , wherein applying a current pulse through the laser diode includes:
during a charging phase, controlling first and second electronic switches to turn ON and charge an inductive element; and
during a firing phase, controlling the second electronic switch to turn OFF to discharge the inductive element and apply the current pulse through the laser diode.

15. The method of claim 10 , wherein applying a bias voltage to the laser diode using the voltage source to decrease the current after firing the laser diode includes:
applying a positive voltage to the cathode of the laser diode relative to a lower power supply rail or ground potential of a laser diode driver circuit.

16. The method of claim 10 , wherein applying a bias voltage to the laser diode using the voltage source to decrease the current after firing the laser diode includes:
applying a negative voltage to the anode of the laser diode relative to an upper power supply rail of a laser diode driver circuit.

17. The method of claim 10 , further comprising:
determining an average current through the laser diode.

18. A diode driver circuit comprising:
a laser diode to receive a pulse of current;
a power supply coupled to an anode of a diode, the power supply configured to apply a static reverse bias across the diode to decrease an anode voltage at the anode of the diode; and
at least one electronic switch configured to control a current through the laser diode.

19. The diode driver circuit of claim 18 , further comprising:
a capacitor coupled to the diode.

20. A diode driver circuit comprising:
a laser diode having an anode and a cathode;
a voltage source coupled to the cathode of the laser diode;
means for applying a current pulse through the laser diode;
means for applying a static reverse bias voltage across the laser diode using the voltage source to decrease the current after firing the laser diode; and
means for adjusting the bias voltage to change a pulse width of the current pulse.

21. The diode driver circuit of claim 20 , further comprising:
a capacitor coupled to the laser diode.

Assignees

• Analog Devices Inc

Inventors

• Kuo Shawn S
• Kapusta Ronald A
• Tang Xu
• Shtargot Leonard
• Cheung Eugene L
• Paolucci Jonathan

Classifications

• H01S5/0428 Primary

  for applying pulses to the laser · CPC title

• H01S5/06216

  Pulse modulation or generation · CPC title

• H01S5/0261

  Non-optical elements, e.g. laser driver components, heaters (H01S5/0265 takes precedence) · CPC title

• H01S5/06808

  by monitoring the electrical laser parameters, e.g. voltage or current · CPC title

• H01S5/06226

  Modulation at ultra-high frequencies · CPC title