High power fiber chirped pulse amplification system utilizing telecom-type components

• US 7,907,334 B2
• Filed: 07/14/2009
• Issued: 03/15/2011
• Est. Priority Date: 06/27/2003
• Status: Active Grant

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: Harter, Donald, Gu, Xinhua, Uehara, Yuzuru
• Primary Examiner(s): BOLDA, ERIC L
• Application Number:
  US12/502,255
• Publication Number:
  US 20090285249A1
• Time in Patent Office: 609 Days
• Field of Search: 359/333, 359/341.1, 372/25
• US Class Current: 359/341.1
• 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 3/0085 Modulating the output, i.e. the laser beam is modulated outside the laser cavity
• CPC Class Codes: H01S 3/06725 Fibre characterized by a specific dispersion, e.g. for pulse shaping in soliton lasers or for dispersion compensating [DCF]
• 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 3/0941 of a laser diode
• CPC Class Codes: H01S 3/1608 erbium
• CPC Class Codes: H01S 3/1618 ytterbium
• CPC Class Codes: H01S 3/2316 Cascaded amplifiers
• CPC Class Codes: H01S 3/2333 Double-pass amplifiers

Abstract

A chirped pulse amplifier (CPA) system having a mode-locked laser and a high-speed pulse selector, wherein the pulse selector modulates output pulses based upon an applied modulation voltage. A pulse selector may be an integrated electro-optic modulator, for example a LiNbO₃ modulator, or an electro-absorption modulator. Difficulties related to free-space alignment and operational stability of some prior designs are reduced or eliminated. Fiber coupling generally simplifies beam delivery and alignment. Some embodiments include an erbium fiber (or erbium-ytterbium) based CPA system operating at a wavelength of approximately 1550 nanometers. Similar performance can be obtained at other wavelengths, for example a 1.06 micrometer Yb-doped fiber system. Moreover, high amplification and peak intensity at the output may be achieved while avoiding non-linear effects in the pulse selector, thereby providing for high intensity picosecond or femtosecond operation.

Claims

1. A fiber-based chirped pulse amplification system, comprising:

a mode-locked laser;

a polarization-maintaining device coupled to an output of the mode-locked laser;

a pulse stretcher and fiber pre-amplifier optically coupled to a first output of the polarization-maintaining device, the stretcher and pre-amplifier configured such that pulses emitted from said mode locked laser are both stretched and pre-amplified with at least two passes through the pulse stretcher and preamplifier;

a first pulse selector coupled to a second output of the polarization-maintaining device;

a fiber power amplifier downstream of the first pulse selector; and

a bulk compressor coupled to an output of said fiber power amplifier, the compressor compressing pulses emitted from said power amplifier to produce ultrashort output pulses.

2. The fiber-based chirped amplification system according to claim 1, wherein the pulse stretcher comprises:

a linearly chirped fiber grating; and

a Faraday rotator.

3. The fiber-based chirped amplification system according to claim 1, wherein the pulse stretcher comprises:

a non-linearly chirped fiber grating; and

a Faraday rotator.

4. The fiber-based chirped amplification system according to claim 1, wherein the pre-amplifier comprises:

an erbium doped fiber amplifier or a erbium/ytterbium or a ytterbium doped fiber amplifier;

a wavelength division multiplexer; and

a diode pump.

5. The fiber-based chirped amplification system according to claim 1, wherein the first pulse selector comprises an electro-optic modulator or an electro-absorption modulator.

6. The fiber-based chirped amplification system according to claim 1, wherein the polarization-maintaining device comprises a polarization-maintaining beam router, wherein a fiber axis orientation of the input and output fibers matches the orientation of the polarization beam splitter.

7. The fiber-based chirped amplification system according to claim 1, wherein the polarization-maintaining device comprises:

a polarization-maintaining beam router, wherein a fiber axis orientation of the input and output fibers matches the orientation of the polarization beam splitter. a Faraday rotator disposed at a first port of the polarization-maintaining beam router; and

a Faraday rotator mirror at that port of the polarization-maintaining beam router in case the optical device is transmissive.

8. The fiber-based chirped amplification system according to claim 1, further comprising:

a second pulse selector coupled to an output of the first pulse selector; and

a synchronization controller that synchronizes the first pulse selector with the second pulse selector.

9. The fiber-based chirped amplification system according to claim 8, wherein the second pulse selector comprises an electro-optic modulator or an electro-absorption modulator.

10. The fiber-based chirped pulse amplification system according to claim 1, wherein a fiber amplifier operating wavelength is about 1550 nanometers or 1060 nanometers.