SINGLE-POLARIZATION HIGH POWER FIBER LASERS AND AMPLIFIERS

• US 20100260214A1
• Filed: 06/15/2010
• Published: 10/14/2010
• Est. Priority Date: 03/16/2001
• Status: Active Grant

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: FERMANN, Martin, HARTER, Donald J.
• Granted Patent: US 8,135,048 B2
• Time in Patent Office: Days
• US Class Current: 372/6
• CPC Class Codes: H01S 3/06708 Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering optical fibres as passive waveguides G02B6/02
• CPC Class Codes: H01S 3/06712 Polarising fibre; Polariser
• CPC Class Codes: H01S 3/06729 Peculiar transverse fibre profile
• CPC Class Codes: H01S 3/094019 Side pumped fibre, whereby pump light is coupled laterally into the fibre via an optical component like a prism, or a grating, or via V-groove coupling
• CPC Class Codes: H01S 3/1118 Semiconductor saturable absorbers, e.g. semiconductor saturable absorber mirrors [SESAMs]; Solid-state saturable absorbers, e.g. carbon nanotube [CNT] based

Abstract

A novel polarization maintaining optical fiber, which can be used as a high-power polarization maintaining fiber laser or amplifier, is described. Insensitivity of the polarization state to external fiber bending and temperature changes is accomplished by minimizing polarization mode-coupling via reducing stresses inside the fiber core via increasing the fiber diameter. Alternatively, polarization mode-coupling can be minimized by an optimization of the fiber coating to minimize stresses at the interface between the fiber and the coating. As a result insensitivity to polarization mode-coupling is obtained at greatly reduced values of birefringence compared to small-diameter fibers. The fiber is of significant use in any application where polarization stability is important, and will be useful in telecommunications applications in particular for reducing polarization mode dispersion. An implementation in a parabolic pulse-producing fiber laser is also described as one specific high power example.

Claims

1. A passively modelocked short-pulse fiber laser, comprising:

a laser cavity having intra-cavity dispersion, and

a birefringent rare-earth-doped gain fiber having a plurality of said air holes arranged in a symmetric or asymmetric pattern.

2. A passively modelocked fiber laser generating short optical pulses as claimed in claim 1, said laser cavity having an intra-cavity self-phase modulation value to substantially broaden a spectrum of the optical pulses prior to output thereof.

3. A passively modelocked fiber laser generating short optical pulses as claimed in claim 2, wherein said modelocked laser is operable to produce an intra-cavity self-phase modulation value substantially greater than pi.

4. A passively modelocked fiber laser generating short optical pulses as claimed in claim 1,

wherein said gain fiber comprises a photonic crystal fiber.