Optical fiber laser equipment

• US 9,190,802 B2
• Filed: 01/16/2015
• Issued: 11/17/2015
• Est. Priority Date: 07/18/2012
• Status: Active Grant

• Current Assignee: Furukawa Electric Company Limited
• Original Assignee: Furukawa Electric Company Limited
• Inventors: Miyato, Taizo, Kashiwagi, Kosuke, Emori, Yoshihiro, Fujisaki, Akira, Kajiwara, Koji
• Primary Examiner(s): Park, Kinam
• Application Number:
  US14/598,691
• Publication Number:
  US 20150214692A1
• Time in Patent Office: 305 Days
• Field of Search: 372/6, 372/29.011
• US Class Current: 1/1
• CPC Class Codes: H01S 3/067 Fibre lasers
• CPC Class Codes: H01S 3/06716 Fibre compositions per se C03C13/04or doping with active elements lasing materials in general H01S3/14
• CPC Class Codes: H01S 3/06733 Fibre having more than one cladding
• CPC Class Codes: H01S 3/0675 Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers
• 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 3/094053 Fibre coupled pump, e.g. delivering pump light using a fibre or a fibre bundle
• CPC Class Codes: H01S 3/0941 of a laser diode
• CPC Class Codes: H01S 3/09415 the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
• CPC Class Codes: H01S 3/1022 by controlling the optical pumping
• CPC Class Codes: H01S 3/1305 Feedback control systems
• CPC Class Codes: H01S 3/1312 by controlling the optical pumping
• CPC Class Codes: H01S 3/1608 erbium
• CPC Class Codes: H01S 3/1618 ytterbium
• CPC Class Codes: H01S 3/2391 emitting at different wavelengths

Abstract

An optical fiber laser device includes optical reflectors making an invisible laser light from an amplification optical fiber; a light source outputting a visible light; an introduction unit outputting the laser light input to a first input terminal from a first output terminal mainly, outputting the visible light input to a second input terminal from the first output terminal mainly, inputting the visible light output by the light source connected to the second input terminal and introducing the visible light to the amplification optical fiber or a output optical fiber via the first output terminal; an optical multiplexer/demultiplexer outputting the visible light to the introduction unit, and outputting a leaking return light input from a side of the introduction unit; and a controller outputting the visible light from the output optical fiber in a case of determining a position at which the laser light will be irradiated.

Claims

1. An optical fiber laser device comprising:

an amplification optical fiber;

a pumping light source outputting a pumping light making the amplification optical fiber be subjected to optical pumping;

optical reflectors being disposed at two sides of the amplification optical fiber and configuring an optical resonator making laser oscillation of an invisible laser light from a light generated in the amplification optical fiber;

an output optical fiber guiding the laser light and outputting the laser light to outside;

a first visible light source outputting a visible light;

an introduction unit having at least first and second input terminals and a first output terminal, the introduction unit having wavelength characteristics of outputting the laser light input to the first input terminal from the first output terminal mainly and outputting the visible light input to the second input terminal from the first output terminal mainly, the introduction unit making the visible light output by the first visible light source input from the second input terminal and introducing the visible light to the amplification optical fiber or the output optical fiber via the first output terminal;

an optical multiplexer/demultiplexer connected to the first visible light source and connected to the second input terminal of the introduction unit, the visible light output by the first visible light source being input to the optical multiplexer/demultiplexer, the visible light being output to the introduction unit, the optical multiplexer/demultiplexer outputting a leaking return light input from a side of the introduction unit; and

a controller driving the first visible light source to output the visible light from the output optical fiber in a case of determining a position on a workpiece, at which the laser light will be irradiated.

2. The optical fiber laser device according to claim 1, further comprising an optical detector being connected to the optical multiplexer/demultiplexer and detecting the leaking return light input to the optical detector.

3. The optical fiber laser device according to claim 2, wherein the optical multiplexer/demultiplexer has wavelength characteristics of transmitting the visible light output by the first visible light source to the side of the introduction unit mainly and outputting the leaking return light to the optical detector mainly.

4. The optical fiber laser device according to claim 2, wherein the optical multiplexer/demultiplexer has optical-branching characteristics of outputting the leaking return light to the first visible light source and the optical detector respectively at a predetermined branch ratio.

5. The optical fiber laser device according to claim 2, further comprising an optical attenuator being disposed between the optical multiplexer/demultiplexer and the optical detector and attenuating the leaking return light mainly.

6. The optical fiber laser device according to claim 2, wherein the controller stops the pumping light source or reduces a pumping-light output in a case where a power of the detected leaking return light is equal to or greater than a first value or equal to or smaller than a second value.

7. The optical fiber laser device according to claim 2, wherein the optical detector is configured to separate the leaking return light to a plurality of wavelength components and detecting an optical power of each wavelength component.

8. The optical fiber laser device according to claim 7, wherein the controller stops the pumping light source or reduces the pumping-light output in a case where a ratio of powers of the respective detected wavelength components is equal to or greater than a predetermined value.

9. The optical fiber laser device according to claim 1, further comprising an optical filter being disposed between the introduction unit and the optical multiplexer/demultiplexer, and having wavelength characteristics of transmitting the visible light therethrough mainly and attenuating the leaking return light mainly.

10. The optical fiber laser device according to claim 1, further comprising an optical filter being disposed between the optical multiplexer/demultiplexer and the first visible light source, and having wavelength characteristics of transmitting the visible light therethrough mainly and attenuating the leaking return light mainly.

11. The optical fiber laser device according to claim 1, wherein

the introduction unit further includes a second output terminal outputting the visible light from the first input terminal mainly in a case where the visible light is input to the second output terminal, and

the second output terminal is provided with at least one of a second visible light source and a second optical detector.

12. The optical fiber laser device according to claim 1, further comprising:

a plurality of the amplification optical fibers and a plurality of the pumping light sources and the optical reflectors corresponding to the amplification optical fibers; and

an optical multiplexer including a plurality of input terminals into which a plurality of the laser lights are input from the plurality of the amplification optical fibers and an output terminal multiplexing the plurality of laser lights and outputting the multiplexed laser lights to the output optical fiber.

13. The optical fiber laser device according to claim 12, wherein the first output terminal of the introduction unit is connected to an unused one of the input terminals of the optical multiplexer.

14. The optical fiber laser device according to claim 12, wherein

the introduction unit further includes a second output terminal capable of outputting the visible light from the first input terminal mainly in a case where the visible light is input to the introduction unit, and

the second output terminal is connected to an unused one of the input terminals of the optical multiplexer.

15. The optical fiber laser device according to claim 1, wherein the introduction unit is of a fiber-fused type or a polished type.

16. The optical fiber laser device according to claim 1, wherein a wavelength of the visible light has a wavelength corresponding to a red color or a green color.

17. The optical fiber laser device according to claim 1, further comprising a radiator being connected to the optical multiplexer/demultiplexer, converting the leaking return light, which is input to the radiator, to heat, and radiating the heat.