Method and system for a pulsed laser source emitting shaped optical waveforms

• US 7,428,253 B2
• Filed: 09/27/2007
• Issued: 09/23/2008
• Est. Priority Date: 09/29/2006
• Status: Expired due to Fees

• Current Assignee: Electro Scientific Industries Incorporated (MKS Instruments Incorporated)
• Original Assignee: 6091571 Canada, Inc. (MKS Instruments Incorporated)
• Inventors: Murison, Richard, Reid, Benoit, Boula-Picard, Reynald, Panarello, Tullio
• Primary Examiner(s): Nguyen; Dung T
• Application Number:
  US11/862,935
• Publication Number:
  US 20080080570A1
• Time in Patent Office: 362 Days
• Field of Search: 372/26, 372/6
• US Class Current: 372/26
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: H01S 3/0085 Modulating the output, i.e. the laser beam is modulated outside the laser cavity
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/10015 by monitoring or controlling, e.g. attenuating, the input signal
• CPC Class Codes: H01S 3/10023 by functional association of additional optical elements, e.g. filters, gratings, reflectors
• CPC Class Codes: H01S 3/10038 Amplitude control
• CPC Class Codes: H01S 3/10046 Pulse repetition rate control H01S3/11 takes precedence
• CPC Class Codes: H01S 3/10069 Memorized or pre-programmed characteristics, e.g. look-up table [LUT]

Abstract

A tunable pulsed laser source includes a seed source adapted to generate a seed signal and an optical circulator having a first port coupled to the seed source, a second port, and a third port. The tunable pulsed laser source also includes a modulator driver adapted to produce a shaped electrical waveform and an amplitude modulator coupled to the modulator driver and adapted to receive the shaped electrical waveform. The amplitude modulator is characterized by a first side coupled to the second port of the optical circulator and a second side. The tunable pulsed laser source further includes a first optical amplifier characterized by an input end and a reflective end. The input end is coupled to the second side of the amplitude modulator. Moreover, the tunable pulsed laser source includes a second optical amplifier coupled to the third port of the optical circulator.

Claims

1. A tunable pulsed laser source comprising:

a seed source adapted to generate a seed signal;

an optical circulator having a first port coupled to the seed source, a second port, and a third port;

a modulator driver adapted to produce a shaped electrical waveform;

an amplitude modulator coupled to the modulator driver and adapted to receive the shaped electrical waveform, wherein the amplitude modulator is characterized by a first side coupled to the second port of the optical circulator and a second side;

a first optical amplifier characterized by an input end and a reflective end, wherein the input end is coupled to the second side of the amplitude modulator; and

a second optical amplifier coupled to the third port of the optical circulator.

2. The tunable pulsed laser source of claim 1 further comprising a high speed digital-to-analog converter configured to provide the shaped electrical waveform.

3. The tunable pulsed laser source of claim 2 wherein the high speed digital-to-analog converter is characterized by a sampling rate of 500 megasamples/second or faster and an analog electrical bandwidth larger than 100 MHz.

4. The tunable pulsed laser source of claim 2 further comprising a computer configured to calculate the digital pattern.

5. The tunable pulsed laser source of claim 1 wherein an output of the tunable pulsed laser source comprises a set of optical pulses.

6. The tunable pulsed laser source of claim 5 wherein the set of optical pulses comprises a first pulse characterized by a first duration and first intensity and a second pulse characterized by a second duration and a second intensity.

7. The tunable pulsed laser source of claim 6 wherein the first duration is different from the second duration and the first intensity is different from the second intensity.

8. The tunable pulsed laser source of claim 5 wherein the set of optical pulses comprises a first pulse characterized by a first duration and first intensity, a second pulse characterized by a second duration and a second intensity, and a third pulse characterized by a third duration and a third intensity.

9. The tunable pulsed laser source of claim 5 wherein the set of optical pulses comprises a plurality of pulses having a same duration and a same intensity.

10. The tunable pulsed laser source of claim 1 wherein an output of the tunable pulsed laser source is characterized by an output pulse shape having a pulse duration and a power spike having a spike duration that is substantially shorter than the pulse duration.

11. The tunable pulsed laser source of claim 10 wherein the spike duration is less than 50% of the pulse duration.

12. A method of providing a laser pulse, the method comprising:

providing a seed signal;

coupling the seed signal to a first port of an optical circulator;

outputting the seed signal from a second port of the optical circulator;

providing a first shaped electrical signal;

coupling the first shaped electrical signal to an electrical port of an amplitude modulator;

outputting a shaped optical pulse to an input end of an optical amplifier;

amplifying the shaped optical pulse to provide an amplified shaped optical pulse;

providing a second shaped electrical signal;

coupling the second shaped electrical signal to the electrical port of the amplitude modulator;

receiving a reshaped optical pulse at the second port of the optical circulator;

and

outputting the reshaped optical pulse at a third port of the optical circulator.

13. The method of claim 12 wherein the first shaped electrical signal is different from the second shaped electrical signal.

14. The method of claim 12 wherein the reshaped optical pulse is characterized by a substantially square shape.

15. The method of claim 12 wherein the reshaped optical pulse is characterized by an increase in intensity as a function of time.

16. The method of claim 12 wherein the reshaped optical pulse is characterized by a decrease in intensity as a function of time.

17. The method of claim 12 wherein a high-speed digital-to-analog converter is used to generate the first shaped electrical signal and second shaped electrical signal, the high speed digital-to-analog converter being characterized by a sampling rate of 500 megasamples/second or faster and an analog electrical bandwidth larger than 100 MHz.

18. The method of claim 12 wherein amplifying the shaped optical pulse is performed using a double pass amplifier.

19. The method of claim 12 wherein the amplified shaped optical pulse is characterized by a pulse duration and a power spike having a spike duration that is substantially shorter than the pulse duration.

20. The method of claim 19 wherein the spike duration is less than 50% of the pulse duration.