Fiber laser apparatus and method of aligning laser light irradiation position

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,

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.

2. The fiber laser apparatus according to claim 1 , 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.

3. The fiber laser apparatus according to claim 1 , 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.

4. The fiber laser apparatus according to claim 3 , wherein the wavelength selective coupling-splitting element is one of a fused fiber type and a polished type.

5. The fiber laser apparatus according to claim 3 , 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.

6. The fiber laser apparatus according to claim 2 , 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.

7. The fiber laser apparatus according to claim 3 , 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.

8. 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,

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,

wherein a core light attenuating section that attenuates core light is disposed between the visible laser light source and the introducing section.

9. 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,

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,

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.

10. 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;

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; and

a cladding light attenuating section that attenuates light that propagates through a cladding of the amplification optical fiber.

11. 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.

12. 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;

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; and

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,

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

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.

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

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

15. The fiber laser apparatus according to claim 10 , 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.

16. The fiber laser apparatus according to claim 10 , 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.

17. The fiber laser apparatus according to claim 10 , wherein a wavelength of the visible laser light has a wavelength corresponding to red or green.