HIGH POWER SHORT PULSE FIBER LASER

• US 20120008649A1
• Filed: 06/14/2010
• Published: 01/12/2012
• Est. Priority Date: 03/31/2004
• Status: Active Grant

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: Gu, Xinhua, Bendett, Mark, Cho, Gyu Cheon
• Granted Patent: US 8,537,864 B2
• Time in Patent Office: Days
• US Class Current: 372/18
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108
• CPC Class Codes: H01S 3/0064 Anti-reflection devices, e.g. optical isolaters absorbing layers for marking or protecting purposes in laser working B23K26/50; magneto-optical non-reciprocal devices G02F1/093, G02F1/0955
• CPC Class Codes: H01S 3/0078 Frequency filtering
• CPC Class Codes: H01S 3/06712 Polarising fibre; Polariser
• CPC Class Codes: H01S 3/06741 Photonic crystal fibre, i.e. the fibre having a photonic bandgap
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/094003 the pumped medium being a fibre
• CPC Class Codes: H01S 3/094042 of a fibre laser
• CPC Class Codes: H01S 3/0941 of a laser diode
• CPC Class Codes: H01S 3/1028 by controlling the temperature
• CPC Class Codes: H01S 3/1115 using intracavity saturable absorbers
• CPC Class Codes: H01S 3/1305 Feedback control systems
• CPC Class Codes: H01S 3/1618 ytterbium
• CPC Class Codes: H01S 3/1698 rare earth

Abstract

A pulsed laser comprises an oscillator and amplifier. An attenuator and/or pre-compressor may be disposed between the oscillator and amplifier to improve performance and possibly the quality of pulses output from the laser. Such pre-compression may be implemented with spectral filters and/or dispersive elements between the oscillator and amplifier. The pulsed laser may have a modular design comprising modular devices that may have Telcordia-graded quality and reliability. Fiber pigtails extending from the device modules can be spliced together to form laser system. In one embodiment, a laser system operating at approximately 1050 nm comprises an oscillator having a spectral bandwidth of approximately 19 nm. This oscillator signal can be manipulated to generate a pulse having a width below approximately 90 fs.

Claims

1. An amplification system for outputting pulses having a pulse width, said amplification system comprising:

a modelocked fiber oscillator producing an optical output comprising a plurality of optical pulses having a pulse width and a spectral power distribution having a bandwidth;

an amplifier disposed external to the modelocked fiber oscillator and optically connected to said modelocked fiber oscillator for amplifying said optical pulses; and

a spectral filter disposed external to the modelocked fiber oscillator and between said oscillator and said amplifier, said spectral filter configured to receive said optical output of said modelocked fiber oscillator prior to reaching said amplifier, said spectral filter having a spectral transmission with a band edge that overlaps said spectral power distribution of said optical output of said modelocked fiber oscillator to attenuate a portion of said spectral power distribution and thereby reduce the spectral bandwidth,

wherein said spectral filter reduces the spectral bandwidth to less than about 12 nanometers, and

wherein said spectral filter reduces the spectral bandwidth by between about 5 nm to 12 nm.

2. The amplification system of claim 1, wherein the pulse width of said optical pulses coupled from said modelocked fiber oscillator is reduced at the output of the system.

3. The amplification system of claim 1, wherein the pulse width of said optical pulses coupled from said modelocked fiber oscillator is reduced at the output of the spectral filter.

4. The amplification system of claim 1, wherein, wherein said spectral filter comprises a filter selected from the group consisting of a bandpass filter, a low pass filter, and a high pass filter.

5. The amplification system of claim 1, wherein said spectral filter comprises a bandpass filter.

6. The amplification system of claim 1, wherein said spectral filter comprises a grating.

7. A pulsed fiber laser amplification system comprising:

a modelocked fiber oscillator outputting optical pulses;

a fiber amplifier optically connected to said modelocked fiber oscillator via a first optical path, said amplifier amplifying said optical pulses;

an optical pump source optically connected to said fiber amplifier;

a pulse compressor optically coupled to receive said amplified optical pulses output from fiber amplifier via a second optical path; and

(i) a first optical tap in said first optical path between said modelocked fiber oscillator and said fiber amplifier, and

a first feedback loop from said first tap to control said modelocked fiber oscillator based on measurement of output from said first optical tap, and

(ii) a second optical tap in said second optical path between said fiber amplifier and said compressor, and

a second feedback loop from said second tap to control said fiber amplifier based on measurement of output from said second optical tap.

8. The pulsed fiber laser amplification system of claim 7, further comprising a variable optical attenuator in the first optical path between said modelocked fiber oscillator and said fiber amplifier.

9. The pulsed fiber laser amplification system of claim 7, further comprising a pre-compressor in the first optical path between said modelocked fiber oscillator and said fiber amplifier.

10. The pulsed fiber laser amplification system of claim 9, wherein said pre-compressor comprises a spectral filter.

11. The pulsed fiber laser amplification system of claim 9, wherein said pre-compressor comprises a dispersive optical element.

12. The pulsed fiber laser amplification system of claim 7, further comprising a first isolator in said first optical path from said oscillator to said fiber amplifier, said first isolator comprising said first tap.

13. The pulsed fiber laser amplification system of claim 7, further comprising a second isolator in said second optical path from said fiber amplifier to said compressor, said second isolator containing said second tap.

14. The pulsed fiber laser amplification system of claim 7, further comprising an oscillator pump that optically pumps said modelocked fiber oscillator, said first feedback loop from said first tap controlling said oscillator pump.

15. The pulsed fiber laser amplification system of claim 7, further comprising a temperature controller in thermal contact with said modelocked fiber oscillator to adjust operation of said modelocked fiber oscillator, said first feedback loop from said first tap controlling said temperature controller.

16. The pulsed fiber laser amplification system of claim 7, further comprising a temperature controller in thermal contact with said fiber amplifier to adjust operation of said fiber amplifier, said second feedback loop from said second tap controlling said temperature controller.

17. The pulsed fiber laser amplification system of claim 7, further comprising a plurality of modular housings coupled together via optical fiber.

18. The pulsed fiber laser amplification system of claim 17, wherein at least a portion of said modelocked fiber oscillator comprises a housing.