Abstract: A laser device includes: a seed light source configured to output a laser light having a single mode; a multicore fiber including at least one core group having at least one core, each of the core in the core group being optically coupled to neighboring cores; and an optical coupler configured to input the laser light to the core group, wherein in the multicore fiber, the laser light propagates through the core group in a super mode representing propagation mode of the core group.

Abstract: An optical processing structure of an optical fiber, includes: an optical fiber that includes a core, a cladding, and a coating, the coating being partially removed; and a thermally conductive protective material made of a silicone-based thermally conductive compound and provided around the cladding in a coating removed region of the optical fiber. Further, the thermally conductive protective material contains a filler having a refractive index higher than a refractive index of the cladding, and the filler is present in a region where evanescent light seeping out of the cladding is present when cladding mode light propagating in the cladding is totally reflected.

Abstract: A fiber laser apparatus that generates invisible laser light using an amplification optical fiber having a core and that propagates a fundamental mode and a low-order mode 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 the amplification optical fiber, a cladding light attenuating section that attenuates light which has propagated through a cladding of the amplification optical fiber, at a subsequent stage of the amplification optical fiber, and a drive unit that drives the visible laser light source to emit the visible laser light through a core of the output optical fiber in a case of performing alignment of an irradiation position of the invisible laser light with respect to a workpiece.

Abstract: An optical fiber laser device generates laser light by using an optical amplifying fiber as an amplification medium in a laser oscillator and includes: an optical outputting fiber configured to emit laser light to an outside; a return-light-attenuating portion configured to perform an attenuation process to return light propagating through at least the optical outputting fiber in a reverse direction of the laser light; a thermal conversion unit provided at the return-light-attenuating portion and configured to convert the return light into heat; a temperature-monitoring device configured to measure an increase in a temperature, of the return-light-attenuating portion, caused by the heat converted by the thermal conversion unit; and a control unit configured to decrease or stop an output of the laser light when the temperature measured by the temperature-monitoring device becomes a predetermined threshold temperature or higher.

Abstract: An optical fiber laser device generates laser light by using an optical amplifying fiber as an amplification medium in a laser oscillator and includes: an optical outputting fiber configured to emit laser light to an outside; a return-light-attenuating portion configured to perform an attenuation process to return light propagating through at least the optical outputting fiber in a reverse direction of the laser light; a thermal conversion unit provided at the return-light-attenuating portion and configured to convert the return light into heat; a temperature-monitoring device configured to measure an increase in a temperature, of the return-light-attenuating portion, caused by the heat converted by the thermal conversion unit; and a control unit configured to decrease or stop an output of the laser light when the temperature measured by the temperature-monitoring device becomes a predetermined threshold temperature or higher.

Abstract: An optical fiber laser device generates laser light by using an optical amplifying fiber as an amplification medium in a laser oscillator and includes: an optical outputting fiber configured to emit laser light to an outside; a return-light-attenuating portion configured to perform an attenuation process to return light propagating through at least the optical outputting fiber in a reverse direction of the laser light; a thermal conversion unit provided at the return-light-attenuating portion and configured to convert the return light into heat; a temperature-monitoring device configured to measure an increase in a temperature, of the return-light-attenuating portion, caused by the heat converted by the thermal conversion unit; and a control unit configured to decrease or stop an output of the laser light when the temperature measured by the temperature-monitoring device becomes a predetermined threshold temperature or higher.

Abstract: A fiber laser apparatus that generates invisible laser light using an amplification optical fiber having a core and that propagates a fundamental mode and a low-order mode 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 the amplification optical fiber, a cladding light attenuating section that attenuates light which has propagated through a cladding of the amplification optical fiber, at a subsequent stage of the amplification optical fiber, and a drive unit that drives the visible laser light source to emit the visible laser light through a core of the output optical fiber in a case of performing alignment of an irradiation position of the invisible laser light with respect to a workpiece.

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.

Abstract: A laser unit includes: multi-mode semiconductor lasers configured to output laser lights in multi-mode; an optical multiplexer configured to multiplex and output the laser lights; a multi-mode optical fiber configured to connect the multi-mode semiconductor lasers to the optical multiplexer, and including a core portion, a cladding portion, and a coated portion; a first bending portion formed to the multi-mode optical fiber and bent with a predetermined bending length and at a predetermined first bending radius; a radiation portion formed outside the coated portion at the first bending portion, and configured to radiate heat of the multi-mode optical fiber; and a second bending portion formed to the multi-mode optical fiber between the first bending portion and the optical multiplexer and bent at a predetermined second bending radius, wherein increase in a temperature at the second bending portion is restrained by radiation from the radiation portion.

Abstract: An optical fiber laser device generates laser light by using an optical amplifying fiber as an amplification medium in a laser oscillator and includes: an optical outputting fiber configured to emit laser light to an outside; a return-light-attenuating portion configured to perform an attenuation process to return light propagating through at least the optical outputting fiber in a reverse direction of the laser light; a thermal conversion unit provided at the return-light-attenuating portion and configured to convert the return light into heat; a temperature-monitoring device configured to measure an increase in a temperature, of the return-light-attenuating portion, caused by the heat converted by the thermal conversion unit; and a control unit configured to decrease or stop an output of the laser light when the temperature measured by the temperature-monitoring device becomes a predetermined threshold temperature or higher.

Abstract: A laser unit includes: multi-mode semiconductor lasers configured to output laser lights in multi-mode; an optical multiplexer configured to multiplex and output the laser lights; a multi-mode optical fiber configured to connect the multi-mode semiconductor lasers to the optical multiplexer, and including a core portion, a cladding portion, and a coated portion; a first bending portion formed to the multi-mode optical fiber and bent with a predetermined bending length and at a predetermined first bending radius; a radiation portion formed outside the coated portion at the first bending portion, and configured to radiate heat of the multi-mode optical fiber; and a second bending portion formed to the multi-mode optical fiber between the first bending portion and the optical multiplexer and bent at a predetermined second bending radius, wherein increase in a temperature at the second bending portion is restrained by radiation from the radiation portion.

Abstract: A Raman amplifier using semiconductor lasers of Fabry-Perot, DFB, or DBR type or MOPAs, to output pumping lights having different central wavelengths, an interval between adjacent central wavelengths greater than 6 nm and smaller than 35 nm. An optical repeater is adapted to compensate loss in an optical fiber transmission line by the Raman amplifier. A Raman amplification method wherein the shorter the central wavelength of the pumping light, the higher light power of the pumping light. In the Raman amplifier, a certain pumping 1 wavelength being a first channel, and second to n-th channels are arranged with an interval of about 1 THz toward a longer wavelength side, pumping lights having wavelengths corresponding to the first to n-th channels are multiplexed, and pumping light having a wavelength spaced apart from the n-th channel by 2 THz or more toward the longer wavelength side is combined with the multiplexed light, thereby forming the pumping light source.

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.

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.

Abstract: A fiber laser apparatus in which pump light is introduced into an optical fiber to generate laser light includes a detecting section that detects signal light leaking out from a core of the optical fiber as leakage signal light, a determining section that determines that, in a case where there is a decrease in an intensity of the leakage signal light detected in the detecting section, a failure of the fiber has occurred, and a stopping section that stops, in a case where the determining section has determined that a failure of the fiber has occurred, the introduction of the pump light into the optical fiber. The detecting section detects the leakage signal light leaking out of a High Reflectivity FBG that is provided on a side opposite to an output side of the laser light.

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.

Abstract: A fiber laser apparatus in which pump light is introduced into an optical fiber to generate laser light includes a detecting section that detects signal light leaking out from a core of the optical fiber as leakage signal light, a determining section that determines that, in a case where there is a decrease in an intensity of the leakage signal light detected in the detecting section, a failure of the fiber has occurred, and a stopping section that stops, in a case where the determining section has determined that a failure of the fiber has occurred, the introduction of the pump light into the optical fiber. The detecting section detects the leakage signal light leaking out of a High Reflectivity FBG that is provided on a side opposite to an output side of the laser light.

Abstract: A Raman amplifier according to the present invention comprises a plurality of pumping means using semiconductor lasers of Fabry-Perot, DFB, or DBR type or MOPAs, and pumping lights outputted from the pumping means have different central wavelengths, and interval between the adjacent central wavelength is greater than 6 nm and smaller than 35 nm. An optical repeater according to the present invention comprises the above-mentioned Raman amplifier and adapted to compensate loss in an optical fiber transmission line by the Raman amplifier. In a Raman amplification method according to the present invention, the shorter the central wavelength of the pumping light the higher light power of said pumping light.

Abstract: An optical fiber holding apparatus in accordance with the present invention is characterized in that the same comprises a surface in order to hold an optical fiber which is to be a state of which is rolled up so as not to overlap with each other, wherein at least the surface is formed of a thermo conductive molding body which has a thermal conductivity to be higher than or equal to 0.5 W/mK, and which has an Asker C hardness to be between twenty and fifty. Or, the same comprises a peripheral surface in order to roll up and hold an optical fiber, wherein at least the peripheral surface is formed of a thermo conductive molding body which has the thermal conductivity to be higher than or equal to 0.5 W/mK, and which has the Asker C hardness to be between twenty and fifty. Moreover, it is desirable for the thermo conductive molding body to have a compressive strength of which a peak value is between ten and thirty N/cm2 and a stabilized value is between three and ten N/cm2.

Abstract: A Raman amplifier according to the present invention comprises a plurality of pumping means using semiconductor lasers of Fabry-Perot, DFB, or DBR type or MOPAs, and pumping lights outputted from the pumping means have different central wavelengths, and interval between the adjacent central wavelength is greater than 6 nm and smaller than 35 nm. An optical repeater according to the present invention comprises the above-mentioned Raman amplifier and adapted to compensate loss in an optical fiber transmission line by the Raman amplifier. In a Raman amplification method according to the present invention, the shorter the central wavelength of the pumping light the higher light power of said pumping light.