Fiber Laser Apparatus and Method of Aligning Laser Light Irradiation Position

• US 20130299474A1
• Filed: 07/17/2013
• Published: 11/14/2013
• Est. Priority Date: 01/18/2011
• Status: Active Grant

• Current Assignee: Furukawa Electric Company Limited
• Original Assignee: Furukawa Electric Company Limited
• Inventors: EMORI, Yoshihiro, KASHIWAGI, Kosuke, FUJISAKI, Akira
• Granted Patent: US 10,141,708 B2
• Time in Patent Office: Days
• US Class Current: 219/121.81
• CPC Class Codes: B23K 26/042 Automatically aligning the laser beam
• CPC Class Codes: H01S 3/067 Fibre lasers
• 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 3/09415 the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
• CPC Class Codes: H01S 3/10038 Amplitude control
• CPC Class Codes: H01S 3/2375 Hybrid lasers H01S3/07 takes precedence
• CPC Class Codes: H01S 3/2391 emitting at different wavelengths

Abstract

A fiber laser apparatus that generates invisible laser light using an amplification optical fiber having a single-mode core and outputs the invisible laser light via an output optical fiber is provided. The fiber laser apparatus includes a visible laser light source that generates visible laser light, an introducing section that introduces the visible laser light generated by the visible laser light source into a core of one of the amplification optical fiber and the output optical fiber, and a drive unit that drives, in a case of performing alignment of an irradiation position of the invisible laser light with respect to a workpiece, the visible laser light source and emits the visible laser light via the core of the output optical fiber.

Claims

1. A fiber laser apparatus that generates invisible laser light using an amplification optical fiber having a single-mode core and outputs the invisible laser light via an output optical fiber, the fiber laser apparatus comprising:

a visible laser light source that generates visible laser light;

an introducing section that introduces the visible laser light generated by the visible laser light source into a core of one of the amplification optical fiber and the output optical fiber; and

a drive unit that drives, in a case of performing alignment of an irradiation position of the invisible laser light with respect to a workpiece, the visible laser light source and emits the visible laser light via the core of the output optical fiber.

2. The fiber laser apparatus according to claim 1, wherein the introducing section introduces the visible laser light generated by the visible laser light source into the core of one of the amplification optical fiber and the output optical fiber, and attenuates return light that propagates through the core in a reverse direction while generating the invisible laser light, the return light being incident on the visible laser light source.

3. The fiber laser apparatus according to claim 2, wherein the return light is an invisible light that has an invisible laser light wavelength and also includes at least one of Raman scattered light generated by the invisible laser light on a longwave side thereof and Brillouin scattered light generated near the invisible laser light wavelength.

4. The fiber laser apparatus according to claim 2, wherein the introducing section has a wavelength selective coupling-splitting element that at least has two input terminals and one output terminal,

the visible laser light from the visible laser light source being entered into one of the input terminals, laser light emitted from the output terminal being introduced into the core of one of the amplification optical fiber and the output optical fiber,

return light that propagates in the reverse direction in the core during generation of the invisible laser light and entered into the output terminal being propagated to the other input terminal, return light that propagates to one of the input terminals being attenuated.

5. The fiber laser apparatus according to claim 4, wherein the wavelength selective coupling-splitting element is one of a fused fiber type and a polished type.

6. The fiber laser apparatus according to claim 4, further comprising an optical resonator that generates the invisible laser light,

the wavelength selective coupling-splitting element being provided on one of an input side and an output side of the optical resonator.

7. The fiber laser apparatus according to claim 3, further comprising an optical resonator that generates the invisible laser light and an optical amplifier that amplifies the invisible laser light generated by the optical resonator,

the wavelength selective coupling-splitting element being provided on an input side of the optical resonator, between optical resonator and the light amplifier, or on an output side of the optical resonator.

8. The fiber laser apparatus according to claim 4, further comprising a filter that attenuates the return light propagating from the wavelength selective coupling-splitting element to one of the input terminals, a pass-band of the filter being visible light, the filter being provided between the visible laser light source and the wavelength selective coupling-splitting element.

9. The fiber laser apparatus according to claim 1, wherein the introducing section has an optical fiber that connects an emitting section of the visible laser light source with a core of the amplification optical fiber.

10. The fiber laser apparatus according to claim 1, wherein the introducing section has a pump light multiplexer that connects an emitting section of the visible laser light source with a cladding of the amplification optical fiber.

11. The fiber laser apparatus according to claim 9, wherein a core light attenuating section that attenuates core light is disposed between the visible laser light source and the introducing section.

12. The fiber laser apparatus according to claim 9, wherein an optical filter that transmits the visible laser light and attenuates the invisible laser light is disposed between the visible laser light source and the introducing section.

13. The fiber laser apparatus according to claim 1, further comprising a cladding light attenuating section that attenuates light that propagates through the cladding of the amplification optical fiber.

14. The fiber laser apparatus according to claim 1, further comprising a plurality of the amplification optical fibers each generating the invisible laser light and a combining unit that receives and combines invisible laser lights outputted from the plurality of amplification optical fibers inputted via a plurality of input ends,

the introducing section introducing the visible laser light to at least one of the input ends of the combining unit.

15. The fiber laser apparatus according to claim 14, wherein the introducing section introduces the visible laser light into an input end whereto invisible laser light from the amplification optical fiber is not inputted, among the plurality of input ends of the combining units.

16. The fiber laser apparatus according to any one of claim 1, wherein a wavelength of the visible laser light has a wavelength corresponding to red or green.

17. A method of aligning a laser light irradiation position in which invisible laser light is generated using an amplification optical fiber having a single-mode core and outputted via an output optical fiber, comprising:

introducing the visible laser light generated by a visible laser light source that generates visible laser light into a core of one of the amplification optical fiber and the output optical fiber; and

determining an irradiation position of the invisible laser light with respect to a workpiece by the visible laser light emitted via the core of the output optical fiber.