Abstract: A laser device includes a light source, an optical fiber, a cable coating, an optical connector, a pair of disconnection detection lines, a pair of open detection lines, and a determination portion. The light source outputs a laser beam. The optical fiber propagates the laser beam. The optical fiber is inserted into the cable coating. The optical connector is connected to a tip of the cable coating. The pair of disconnection detection lines include a first disconnection detection line and a second disconnection detection line. The pair of open detection lines include a first open detection line and a second open detection line.

Abstract: A laser device includes a light source, an optical fiber, a cable coating, an optical connector, a pair of disconnection detection lines, a pair of open detection lines, and a determination portion. The light source outputs a laser beam. The optical fiber propagates the laser beam. The optical fiber is inserted into the cable coating. The optical connector is connected to a tip of the cable coating. The pair of disconnection detection lines include a first disconnection detection line and a second disconnection detection line. The pair of open detection lines include a first open detection line and a second open detection line.

Abstract: A fiber laser device 1 includes: a pumping light source 10 that emits pumping light; an amplification optical fiber 30 that amplifies and emits signal light by the pumping light; a detector 71 that detects a power of stimulated Raman scattering light generated from the signal light propagated through the amplification optical fiber 30 or the signal light emitted from the amplification optical fiber 30 in preference to a power of the signal light; and a controller 80 that controls a power of the pumping light based on the power of the light detected by the detector 71.

Abstract: A fiber laser includes: an amplification optical fiber; a pumping light source configured to emit pumping light to pump the active element of the amplification optical fiber; a first mirror provided on one side of the amplification optical fiber; and a second mirror provided on the other side of the amplification optical fiber. When an optical loss between the first mirror and the second mirror is equal to an optical gain in the amplification optical fiber, a difference between a gain of light having a wavelength at which a gain becomes maximum and a gain of light having a wavelength reflected off the first mirror and the second mirror is 35 dB or less in the amplification optical fiber.

Abstract: A fiber laser device includes: a pumping light source that emits pumping light; an amplification optical fiber that amplifies signal light using the pumping light and emits the signal light; a first FBG that is provided on one side of the amplification optical fiber and reflects the signal light; a second FBG that is provided on the other side of the amplification optical fiber and reflects the signal light at a reflectance lower than a reflectance of the first FBG; a detecting unit that detects with priority to light in a wavelength range between a wavelength 15 nm below and above the maximum reflection wavelength range, in which the reflectance of the first FBG is at the maximum, among lights at the other wavelengths in the light passed through the first FBG from the amplification optical fiber side.

Abstract: An object of the present invention is to provide an optical multiplexer and a fiber laser for obtaining high-output light of a single wavelength. The optical multiplexer according to the present invention is provided with input units 11 and 12, a wavelength multiplexing unit 14, a multiplexed light converting unit 15 and an output unit 16. Lights of a plurality of wavelengths ?1 and ?2 are input to the input units 11 and 12, respectively. The wavelength multiplexing unit 14 wavelength-multiplexes the lights of the plurality of wavelengths ?1 and ?2 input from the input units 11 and 12 different for each wavelength to one multiplexed light. By wavelength-multiplexing, it is possible to multiplex without a loss.

Abstract: A fiber laser device includes: a pumping light source that emits pumping light; an amplification optical fiber that amplifies signal light using the pumping light and emits the signal light; a first FBG that is provided on one side of the amplification optical fiber and reflects the signal light; a second FBG that is provided on the other side of the amplification optical fiber and reflects the signal light at a reflectance lower than a reflectance of the first FBG; a detecting unit that detects with priority to light in a wavelength range between a wavelength 15 nm below and above the maximum reflection wavelength range, in which the reflectance of the first FBG is at the maximum, among lights at the other wavelengths in the light passed through the first FBG from the amplification optical fiber side.

Abstract: A fiber laser includes: an amplification optical fiber; a pumping light source configured to emit pumping light to pump the active element of the amplification optical fiber; a first mirror provided on one side of the amplification optical fiber; and a second mirror provided on the other side of the amplification optical fiber. When an optical loss between the first mirror and the second mirror is equal to an optical gain in the amplification optical fiber, a difference between a gain of light having a wavelength at which a gain becomes maximum and a gain of light having a wavelength reflected off the first mirror and the second mirror is 35 dB or less in the amplification optical fiber.

Abstract: An optical fiber laser including: a master oscillator; and a power amplifier, the power amplifier including: a plurality of excitation light sources; excitation ports each of which is connected to the excitation light sources and which an excitation light emitted from each of the excitation light source enters; a signal port which a laser beam emitted from the master oscillator enters; an optical coupler with an exit port that outputs the excitation lights from the excitation ports together with the laser beam from the signal port; and an optical fiber connected to the exit port, in which the optical fiber is a photonic bandgap fiber, and the optical fiber has a loss wavelength characteristic in that a photonic bandgap region is narrower than a gain wavelength band in a graph with an axis of abscissa representing a wavelength and an axis of ordinate representing a loss amount.

Abstract: This fiber laser is provided with: a signal light source that outputs a signal light; a rare earth-doped fiber that amplifies and outputs the signal light from the signal light source; a Raman amplifying fiber that is routed as a portion of an optical transmission path in order to output the output light from the rare earth-doped fiber to an outside thereof; and a wavelength selecting element that is provided in the optical transmission path from the Raman amplifying fiber to the signal light source and does not allow transmission of a Stokes light that is generated in the Raman amplifying fiber.

Abstract: An optical fiber amplifier (2) includes: a first pumping source (10); a second pumping source (20); an amplification optical fiber (3) in which an active element is doped; a first optical filter (15) coupled to the first pumping source (10) and one end of the amplification optical fiber (30), the first optical filter (15) transmitting a light at a wavelength the same as the wavelength of a first pumping light and reflecting a light at a wavelength the same as the wavelength of a second pumping light; and a second optical filter (25) coupled to the second pumping source (20) and the other end of the amplification optical fiber (3), the second optical filter (25) transmitting a light at a wavelength the same as the wavelength of the second pumping light and reflecting a light at a wavelength the same as the wavelength of the first pumping light.

Abstract: A fiber output stabilizer according to an aspect of the invention stabilizes output light from a rare-earth doped optical fiber in which at least one kind of a rare-earth element is added to a core. The fiber output stabilizer includes: a monitoring light source that emits monitoring light having a wavelength shorter than that of excitation light exciting the rare-earth element; an optical multiplexer that multiplexes the monitoring light into the excitation light; an optical demultiplexer that demultiplexes the monitoring light passing through the rare-earth doped optical fiber; and a passing light detector that detects light intensity of the monitoring light from the optical demultiplexer.

Abstract: A rare earth-doped core optical fiber of the present invention includes a core comprising a silica glass containing at least aluminum and ytterbium, and a clad provided around the core and comprising a silica glass having a lower refraction index than that of the core, wherein the core has an aluminum concentration of 2% by mass or more, and ytterbium is doped into the core at such a concentration that the absorption band which appears around a wavelength of 976 nm in the absorption band by ytterbium contained in the core shows a peak absorption coefficient of 800 dB/m or less.

Abstract: An optical fiber laser including: a master oscillator; and a power amplifier, the power amplifier including: a plurality of excitation light sources; excitation ports each of which is connected to the excitation light sources and which an excitation light emitted from each of the excitation light source enters; a signal port which a laser beam emitted from the master oscillator enters; an optical coupler with an exit port that outputs the excitation lights from the excitation ports together with the laser beam from the signal port; and an optical fiber connected to the exit port, in which the optical fiber is a photonic bandgap fiber, and the optical fiber has a loss wavelength characteristic in that a photonic bandgap region is narrower than a gain wavelength band in a graph with an axis of abscissa representing a wavelength and an axis of ordinate representing a loss amount.

Abstract: A fiber laser device includes a pumping light source configured to output pumping light having a wavelength ?, and a rare earth-doped fiber, wherein when the intensity change rate of the pumping light with respect to the temperature is denoted by ?P dB/° C., the wavelength change rate of the pumping light with respect to the temperature is denoted by ??p nm/° C., the pumping light absorption change rate of the rare earth-doped fiber per unit wavelength change at the wavelength of ? nm when the wavelength of the pumping light changes is denoted by A?(?) dB/nm, and the pumping light absorption change amount of the rare earth-doped fiber per unit temperature change at the wavelength of ? nm when the temperature of the rare earth-doped fiber changes is denoted by ?A(?) dB/° C., the wavelength ? of the pumping light is such a wavelength ? that ?P, ??p×A?(?) and ?A(?) compensate with each other.

Abstract: An MO-PA fiber laser having a master oscillator; and a first power amplifier which uses as a gain medium, a rare earth-doped optical fiber which is connected to a later stage of the master oscillator, wherein the MO-PA fiber laser has a wavelength conversion portion between the master oscillator and the power amplifier, and has a wavelength filter between the wavelength conversion portion and the master oscillator which only allows wavelength components of pulse light emitted from the master oscillator to pass, thereby making it possible to prevent breakage to a fiber laser which is caused by reflection light without using high-cost optical components.

Abstract: A fiber laser of an MOPA type includes an MO which is a laser oscillator for generating seed light, a PA which is a light amplifier connected to a rear stage of the MO, for amplifying and outputting laser light emitted from the MO, and a reflection device which is provided between the MO and the PA. According to the present invention, the MOPA type fiber laser can decrease the peak value of the pulse which is emitted toward the MO or the pump light source by self-oscillation or reflection, and makes it unlikely that the pump light source or the MO will be damaged.

Abstract: An optical fiber laser including: a master oscillator; and a power amplifier, the power amplifier including: a plurality of excitation light sources; excitation ports each of which is connected to the excitation light sources and which an excitation light emitted from each of the excitation light source enters; a signal port which a laser beam emitted from the master oscillator enters; an optical coupler with an exit port that outputs the excitation lights from the excitation ports together with the laser beam from the signal port; and an optical fiber connected to the exit port, in which the optical fiber is a photonic bandgap fiber, and the optical fiber has a loss wavelength characteristic in that a photonic bandgap region is narrower than a gain wavelength band in a graph with an axis of abscissa representing a wavelength and an axis of ordinate representing a loss amount.

Abstract: A fiber laser device capable of performing processing and measurement stably even when the temperature of the use environment changes is provided. The fiber laser device includes: a pumping light source 20 configured to output pumping light having a wavelength ?; and a rare earth-doped fiber, wherein when the intensity change rate of the pumping light with respect to the temperature is denoted by ?P dB/° C., the wavelength change rate of the pumping light with respect to the temperature is denoted by ??p nm/° C., the pumping light absorption change rate of the rare earth-doped fiber 50 per unit wavelength change at the wavelength of ? nm when the wavelength of the pumping light changes is denoted by A? (?) dB/nm, and the pumping light absorption change amount of the rare earth-doped fiber 50 per unit temperature change at the wavelength of ? nm when the temperature of the rare earth-doped fiber 50 changes is denoted by ?A (?) dB/° C.

Abstract: An object of the present invention is to provide an optical multiplexer and a fiber laser for obtaining high-output light of a single wavelength. The optical multiplexer according to the present invention is provided with input units 11 and 12, a wavelength multiplexing unit 14, a multiplexed light converting unit 15 and an output unit 16. Lights of a plurality of wavelengths ?1 and ?2 are input to the input units 11 and 12, respectively. The wavelength multiplexing unit 14 wavelength-multiplexes the lights of the plurality of wavelengths ?1 and ?2 input from the input units 11 and 12 different for each wavelength to one multiplexed light. By wavelength-multiplexing, it is possible to multiplex without a loss.