WO2012099166A1 - レーザ装置 - Google Patents
レーザ装置 Download PDFInfo
- Publication number
- WO2012099166A1 WO2012099166A1 PCT/JP2012/050963 JP2012050963W WO2012099166A1 WO 2012099166 A1 WO2012099166 A1 WO 2012099166A1 JP 2012050963 W JP2012050963 W JP 2012050963W WO 2012099166 A1 WO2012099166 A1 WO 2012099166A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- optical amplifier
- signal light
- fiber optical
- light
- gain
- Prior art date
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/0912—Electronics or drivers for the pump source, i.e. details of drivers or circuitry specific for laser pumping
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
- H04B10/564—Power control
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S2301/00—Functional characteristics
- H01S2301/02—ASE (amplified spontaneous emission), noise; Reduction thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/0014—Monitoring arrangements not otherwise provided for
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06754—Fibre amplifiers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/10007—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers
- H01S3/10015—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers by monitoring or controlling, e.g. attenuating, the input signal
Definitions
- the present invention relates to a laser device that amplifies and outputs signal light by a fiber optical amplifier.
- a laser apparatus that amplifies and outputs signal light with a fiber optical amplifier is widely used as a light source for, for example, a microscope, a shape measuring apparatus, and an exposure apparatus.
- the output wavelength of the laser apparatus is set according to the application and function of the apparatus to be incorporated, and a fiber optical amplifier doped with a pumping medium corresponding to the output wavelength is used.
- a fiber optical amplifier for example, an erbium-doped fiber optical amplifier (EDFA) doped with erbium (Er) in a silica-based optical fiber, and an ytterbium-doped fiber optical amplifier (YDFA) doped with ytterbium (Yb). And the like are known (see Patent Document 1 and Patent Document 2).
- the fiber optical amplifier has amplification characteristics corresponding to the laser medium doped in the core.
- the amplification band of YDFA (ytterbium-doped fiber optical amplifier) is mainly 1030 to 1100 nm.
- YDFA ytterbium-doped fiber optical amplifier
- the entrance / exit surface of the fiber or the entrance / exit surface of the wavelength conversion optical element that converts the wavelength of the light emitted from the fiber optical amplifier, etc. may be contaminated with a place other than the amplifying unit of the YDFA in the excited state.
- spontaneous emission light ASE light: Amplified Spontaneous Emission
- the amplified light propagating in the fiber and the output light emitted are high in the same manner as described above, and there is a problem that the fiber optical amplifier itself and peripheral optical elements may be damaged.
- the reflection on the input / output surface of the fiber optical amplifier or the input / output surface of the wavelength conversion optical element that converts the wavelength of the light output from the fiber optical amplifier may cause some reflection outside the amplification unit of the fiber optical amplifier.
- YDFA When YDFA is excited in the presence of a body, ASE light may be reflected back into the fiber, which may oscillate. As a result, there has been a problem that the fiber optical amplifier itself and peripheral optical elements may be damaged.
- the present invention has been made in view of the above circumstances, and an object thereof is to provide a laser device that can prevent unintended oscillation in a fiber optical amplifier.
- 1st aspect which illustrates this invention is a laser apparatus, Comprising: The fiber optical amplifier which has a gain in the wavelength band containing signal light, amplifies and emits signal light, and the signal light propagated to a fiber optical amplifier And a control unit that controls the excitation power for exciting the fiber optical amplifier, and the control unit detects the intensity of the signal light detected by the signal light detector below a predetermined signal reference value. Then, the excitation power supplied to the fiber optical amplifier is suppressed.
- the predetermined signal reference value is a gain of light having a wavelength higher than that of the signal light in the gain distribution of the fiber optical amplifier that increases with a decrease in the intensity of the signal light propagated to the fiber optical amplifier. Is preferably set based on the intensity of the signal light when it becomes equal to the oscillation threshold. In addition, the time until the excitation power is suppressed after the intensity of the signal light detected by the signal light detector is equal to or lower than the predetermined signal reference value is accompanied by a decrease in the intensity of the signal light incident on the fiber optical amplifier.
- the gain distribution of the rising fiber optical amplifier is preferably set based on the time until the gain of light having a higher gain than the signal light becomes equal to the oscillation threshold.
- an ASE photodetector that detects light having a wavelength higher than the signal light in the gain distribution of the fiber optical amplifier that is emitted from the fiber optical amplifier is provided, and the control unit is detected by the ASE photodetector. It is preferable that the excitation power is suppressed when the intensity of the spontaneous emission light is equal to or higher than a predetermined ASE reference value.
- the predetermined ASE reference value is preferably set based on the intensity of spontaneous emission light when the gain of light having a higher gain than the signal light in the fiber optical amplifier is equal to the oscillation threshold.
- the time until the excitation power is suppressed after the intensity of the spontaneous emission light detected by the ASE photodetector becomes equal to or higher than a predetermined reference value is a wavelength of light having a higher gain than the signal light in the fiber optical amplifier. Is preferably set based on the time until the gain becomes equal to the oscillation threshold.
- the ASE photodetector is provided on the signal light incident side in the fiber optical amplifier and detects the backward propagating spontaneous emission light toward the incident side of the fiber optical amplifier.
- a laser apparatus includes a fiber optical amplifier that has a gain in a wavelength band including signal light, amplifies the signal light, and emits the signal light, and a gain of the fiber optical amplifier that emits from the fiber optical amplifier.
- An ASE photodetector that detects light having a wavelength higher than the signal light in the distribution, and a control unit that controls the pumping power of the fiber optical amplifier, and the control unit detects spontaneous emission detected by the ASE photodetector.
- the pump power for exciting the fiber optical amplifier is suppressed.
- the predetermined ASE reference value may be set based on the intensity of the spontaneous emission light when the gain of light having a higher gain than the signal light in the fiber optical amplifier becomes equal to the oscillation threshold.
- the time until the excitation power is suppressed after the intensity of the spontaneous emission light detected by the ASE photodetector becomes equal to or higher than a predetermined ASE reference value is a wavelength having a gain higher than that of the signal light in the fiber optical amplifier. It is preferable to set based on the time until the light gain becomes equal to the oscillation threshold. Further, it is preferable that the ASE photodetector is provided on the signal light incident side in the fiber optical amplifier and detects the backward propagating spontaneous emission light toward the incident side of the fiber optical amplifier.
- a signal light detector for detecting the signal light propagated to the fiber optical amplifier is provided, and the control unit is excited when the intensity of the signal light detected by the signal light detector is below a predetermined signal reference value. It is preferable to configure so as to suppress power.
- the predetermined signal reference value is the oscillation threshold value of the gain of light having a wavelength higher than that of the signal light in the gain distribution of the fiber optical amplifier that increases with a decrease in the intensity of the signal light incident on the fiber optical amplifier.
- the time until the excitation power is suppressed after the intensity of the signal light detected by the signal light detector is equal to or lower than the predetermined signal reference value is accompanied by a decrease in the intensity of the signal light incident on the fiber optical amplifier.
- the gain distribution of the rising fiber optical amplifier is preferably set based on the time until the gain of light having a higher gain than the signal light becomes equal to the oscillation threshold.
- the ASE photodetector is provided on the incident side of the signal light in the fiber optical amplifier, and the fiber optical amplifier is configured to detect the backward propagating spontaneous emission light toward the incident side. Can also.
- an optical fiber coupler having four ports is provided on the incident side of the fiber optical amplifier, and the signal light, the fiber optical amplifier, the signal photodetector, and the ASE photodetector are connected. It is preferable to configure.
- the fiber optical amplifier is an ytterbium-doped fiber optical amplifier using ytterbium as an excitation medium, and the wavelength of the signal light is preferably in the 1.06 ⁇ m band.
- the pumping power is suppressed when the intensity of the signal light incident on the fiber optical amplifier becomes a predetermined signal reference value or less, and the gain of the fiber optical amplifier is reduced. The Therefore, it is possible to provide a laser apparatus that can prevent unintentional oscillation of the fiber optical amplifier due to the incident state of signal light.
- the excitation power is suppressed even when the intensity of the spontaneous emission light generated by the fiber optical amplifier is equal to or higher than a predetermined ASE reference value.
- the gain of the amplifier is reduced. Therefore, it is possible to provide a laser device that can prevent unintentional oscillation of the fiber optical amplifier due to spontaneous emission light.
- the laser device of the second aspect of the present invention when the intensity of the spontaneous emission light generated in the fiber optical amplifier exceeds a predetermined ASE reference value, the excitation power is suppressed and the gain of the fiber optical amplifier is reduced. Is done. Therefore, it is possible to provide a laser device that can prevent unintentional oscillation of the fiber optical amplifier due to spontaneous emission light.
- the excitation power is suppressed even when the intensity of the signal light incident on the fiber optical amplifier is equal to or lower than a predetermined signal reference value, and the fiber optical amplifier The gain is reduced. Therefore, it is possible to provide a laser apparatus that can prevent unintentional oscillation of the fiber optical amplifier due to the incident state of signal light.
- FIG. 1 is a schematic configuration diagram illustrating a laser device having a first configuration according to the first aspect of the present invention.
- FIG. 2 is a simulation result illustrating the time change of the gain in the wavelength 1030 nm band when the signal light is suddenly interrupted in a state where the ytterbium-doped fiber optical amplifier is excited in the first embodiment of the present invention.
- FIG. 3 is an experimental result of observing the suppression state of the excitation current by the involuntary oscillation preventing device in the first aspect of the present invention.
- FIG. 4 is a schematic configuration diagram illustrating the laser device of the second configuration mode in the first aspect of the present invention.
- FIG. 5 is a connection configuration example of an optical fiber coupler in the first aspect of the present invention.
- FIG. 6 is a connection configuration example using a partial reflection mirror or the like in the first embodiment of the present invention.
- FIG. 7 is a schematic configuration diagram illustrating the laser device of the third configuration mode in the second mode of the present invention.
- FIG. 8 is a simulation result illustrating the time change of the gain in the wavelength 1030 nm band when the signal light is suddenly interrupted in a state where the ytterbium-doped fiber optical amplifier is excited in the second aspect of the present invention.
- FIG. 9 is a schematic configuration diagram illustrating a laser device having a fourth configuration form according to the second aspect of the present invention.
- FIG. 10 shows a connection configuration example of the optical fiber coupler in the second aspect of the present invention.
- FIG. 11 is a connection configuration example using a partial reflection mirror or the like in the second aspect of the present invention.
- FIG. 12 shows the experimental results of observing the suppression state of the excitation current by the involuntary oscillation preventing device in the second aspect of the present invention.
- FIG. 1 shows a schematic configuration diagram of a laser apparatus 1 having a first configuration according to the first aspect of the present invention.
- the laser device 1 operates the signal light generation unit 10 that generates signal light, the amplification unit 20 that amplifies and emits the signal light generated by the signal light generation unit, and the operation of the signal light generation unit 10 and the amplification unit 20.
- a control device 40 to be controlled.
- the signal light generator 10 is a part that generates the signal light amplified by the amplifier 20, and includes a laser light source 11 such as a semiconductor laser, a bulk solid-state laser, or a fiber laser.
- a DFB semiconductor laser is used as the laser light source 11, and an external modulator 15 such as an electro-optic modulation element (EOM), an acousto-optic modulation element (AOM), or a semiconductor optical amplifier (SOA) is also provided.
- EOM electro-optic modulation element
- AOM acousto-optic modulation element
- SOA semiconductor optical amplifier
- the DFB semiconductor laser can be oscillated with CW and pulse, and can control the pulse waveform of the output light at high speed by controlling the current waveform, and can be narrow band in a predetermined wavelength range by controlling the temperature. It is possible to output single-wavelength pulsed light.
- pulse light having a wavelength of 1064 nm, a repetition frequency of 2 MHz, and an ON time of about 10 nsec is emitted from the laser light source 11, and 1 to 2 nsec is cut out by the external modulator 15 to output pulse light having a short ON time.
- An example of the configuration will be shown.
- the external modulator 15 is used in this manner, chirp (frequency modulation) generated when the laser light source 11 is directly pulse-oscillated can be suppressed, and pulsed light close to the Fourier limit can be generated.
- the signal light generator 10 can output pulsed signal light having a very narrow bandwidth and high monochromaticity.
- the signal light Ls generated by the signal light generator 10 is incident on the amplifier 20 via the isolator 17.
- the amplification unit 20 is mainly composed of a fiber optical amplifier 21 that amplifies the signal light Ls.
- a fiber optical amplifier that amplifies signal light having a wavelength of 1064 nm an ytterbium-doped fiber optical amplifier (YDFA) having a gain in a wavelength band of 1030 to 1100 nm is preferably used.
- the fiber optical amplifier 21 includes an optical fiber 22 having a core doped with ytterbium (Yb), a pump light source 23 for exciting Yb, a control unit 25 for controlling pumping power supplied to the pump light source 23, and the like.
- a fiber having a double clad structure is used as the optical fiber 22, the signal light Ls output from the laser light output unit 10 is incident on the core via the pump combiner 24, and is output from the pump light source 23. Excitation light having a wavelength of 976 nm is incident on the first cladding.
- the control unit 25 is provided with a current source 26 that generates excitation power and a power breaker 55 that interrupts the supply of the generated excitation power to the pump light source 23 at high speed.
- the optical fiber 22 may be a single-clad fiber, or the amplifier 20 may be configured by connecting a plurality of fiber optical amplifiers in series or in parallel.
- the control device 40 controls the operation of the signal light generating unit 10 and the amplifying unit 20, and the signal light generated by the signal light generating unit 10 and amplified by the amplifying unit 20 to a power of several W to several tens W (for convenience)
- the laser device 1 outputs La (referred to as amplified light).
- an involuntary oscillation preventing device 50 for preventing the fiber optical amplifier 21 from causing unintended oscillation.
- the involuntary oscillation preventing device 50 ⁇ / b> A of the first configuration form includes a signal light detector 51 that detects the signal light Ls incident on the fiber optical amplifier 21, and a power breaker 55 provided in the control unit 25.
- the signal light detector 51 is provided on an optical path branched from between the laser light source 11 and the fiber optical amplifier 21.
- a partial reflection mirror 53 that reflects signal light by about 1 to several percent, a signal light, and the like.
- a part of the signal light Ls emitted from the signal light generator 10 is input through a melt-stretching type branching coupler or the like that branches about 1 to several percent of the above.
- the signal light detector 51 is a high-speed infrared light sensor having a band on the order of MHz or higher. For example, a sensor using an InGaAs photodiode can be used.
- a detection signal from the signal light detector 51 is input to the control unit 25.
- the control unit 25 instructs the power breaker 55 to suppress power supply to the pump light source 23 when the intensity of the signal light Ls detected by the signal light detector 51 becomes equal to or less than a predetermined signal reference value. And the supply of excitation power from the current source 26 to the pump light source 23 is suppressed.
- the above-mentioned “signal reference value” is based on the magnitude of the gain in the wavelength 1030 nm band that increases with the intensity of the signal light Ls incident on the optical fiber 22 when the fiber optical amplifier 21 is excited. Is set.
- the inversion distribution ratio of Yb increases with the decrease in the signal light intensity, and the gain distribution as a whole gains.
- the gain is higher in the wavelength 1030 nm band than in the wavelength 1064 nm.
- the increased gain of the wavelength 1030 nm exceeds the oscillation threshold (that is, the one-way gain of the wavelength 1030 nm is higher than that of the fiber optical amplifier 21.
- the fiber optical amplifier 21 oscillates at 1030 nm.
- the “signal reference value” is set based on the intensity of the signal light when the gain in the 1030 nm band becomes equal to the oscillation threshold in the gain distribution that increases as the intensity of the signal light Ls incident on the fiber optical amplifier 21 decreases. The For example, it is set equal to or greater than the intensity of the signal light Ls or a value added with a predetermined margin.
- the signal reference value is set and stored in a memory (not shown) provided in the control unit 25.
- the time from when the intensity of the signal light Ls detected by the signal light detector 51 becomes equal to or lower than the signal reference value until the excitation power is substantially cut off by the power breaker 55 is a signal incident on the fiber optical amplifier 21.
- the gain distribution is set based on the time until the gain in the 1030 nm band becomes equal to the oscillation threshold, and is equal to or less than that time, for example, zero to several tenths of that time. Set within.
- the set time is set and stored in a memory (not shown) provided in the control unit 25.
- the signal light Ls is incident on the fiber optical amplifier 21 while the power of the signal light Ls incident on the fiber optical amplifier 21 is 0.5 W and the power of the pumping light from the pump light source 23 is 120 W.
- FIG. 2 shows the simulation result of the time change of the gain in the wavelength 1030 nm band when the signal is suddenly interrupted.
- the horizontal axis represents the elapsed time from when the incidence of the signal light Ls was interrupted, and the vertical axis represents the gain of light having a wavelength of 1030 nm.
- the fiber optical amplifier 21 had a length of 3 m, a core diameter of 25 ⁇ m, a cladding diameter of 250 ⁇ m, and the concentration of Yb added to the core was 6.9 ⁇ 10 25 / m 3 .
- the inversion distribution rate of Yb increases rapidly, and the gain g at a wavelength of 1030 nm increases exponentially with time.
- the oscillation threshold depends on the amount of reflected light remaining in the fiber optical amplifier 21 and varies depending on the configuration of the fiber optical amplifier. Assuming that the return loss of the fiber optical amplifier 21 is ⁇ 50 dB, oscillation occurs at 1030 nm when the one-way gain exceeds 50 dB. From FIG. 2, it can be seen that oscillation occurs in about 10 ⁇ sec from the time when the signal light Ls is interrupted.
- the time until the one-way gain of the fiber optical amplifier 21 exceeds the return loss is almost inversely proportional to the power of the pumping light, when the power of the pumping light is larger, oscillation occurs in a shorter time, and When the power is smaller, oscillation takes longer time. If the excitation power is substantially cut off within about 6 to 8 ⁇ sec from when the incident power of the signal light Ls is greatly reduced, the increase of the inversion distribution can be suppressed and the fiber optical amplifier 21 can be prevented from causing unintended oscillation. be able to.
- the control unit 25 when the detection signal input from the signal light detector 51 becomes equal to or less than the signal reference value, the control unit 25 outputs a command signal for cutting off the power supply to the power breaker 55.
- the supply of excitation power from the current source 26 to the pump light source 23 is cut off within a few ⁇ sec.
- the signal light Ls is 1 to 3 ⁇ se corresponding to 2 to 6 light pulses (for example, 2 ⁇ se corresponding to 4 pulses).
- a configuration in which the supply of excitation power to the pump light source 23 is immediately interrupted when it is not detected is exemplified.
- Fig. 3 shows the experimental results of observing the interruption state of the excitation current by the involuntary oscillation prevention device.
- the horizontal axis represents time (1 ⁇ sec / div)
- the vertical axis represents the excitation power and the light intensity of the signal light Ls.
- the excitation power to the pump light source 23 is cut off after confirming that it has been interrupted for 2 ⁇ s corresponding to four light pulses, and the time required for the power breaker 55 to cut off the excitation power. Is less than 1 ⁇ sec.
- the pumping power is increased before the gain of the wavelength 1030 nm rises to the oscillation threshold.
- the fiber optical amplifier 21 can be prevented from causing unintended oscillation.
- the laser light source 11 is turned off while the fiber optical amplifier 21 is excited, for example, the laser light source 11 or the external modulator 15 is broken or disconnected, the laser light source 11 and the fiber light amplification.
- the fiber optical amplifier 21 is prevented from causing unintended oscillation. As a result, it is possible to prevent the constituent members from being damaged.
- FIG. 4 shows a schematic configuration of the entire laser device 2 including the involuntary oscillation preventing device 50B.
- the same components as those of the laser device 1 are denoted by the same reference numerals, and redundant description is omitted.
- the involuntary oscillation preventing device 50B of the second configuration form includes an ASE photodetector 52 that detects light in the wavelength 1030 nm band emitted from the fiber optical amplifier 21 in addition to the involuntary oscillation prevention device 50A of the first configuration form. Configured.
- a 4-port 2 ⁇ 2 melt-stretching optical fiber coupler 54 as shown in FIG. 5 is provided between the laser light source 11 and the fiber optical amplifier 21.
- the signal light Ls, the fiber optical amplifier 21, the above-described signal light detector 51, and the ASE light detector 52 are combined.
- the optical fiber coupler 54 has a branching ratio of 99: 1, for example, branches 1% of the signal light Ls incident from the signal light generating unit 10 side to the signal light detector 51, and is generated by the fiber optical amplifier 21 to be incident side. 1% of the backward propagating spontaneously emitted light (Backward ASE light) that travels to the ASE photodetector 52 can be branched.
- FIG. 5 illustrates a configuration provided with a bandpass filter BPF that transmits only backward propagation spontaneous emission light having a wavelength of 1030 nm.
- signal light is generated by using a wavelength-selective partial reflection mirror that transmits 99% of light with a wavelength of 1064 nm (1% reflection) while totally reflects light with a wavelength of 1030 nm.
- Reflected light having a wavelength of 1064 nm that is incident and reflected from the side of the unit 10 is incident on the signal light detector 51, and ASE light having a wavelength of 1030 nm that is incident and reflected from the side of the amplifying unit 20 is incident on the ASE photodetector 52.
- You may comprise so that it may be made.
- a partial reflection mirror 541 that transmits 99% of light with a wavelength of 1064 nm (1% reflection) and a dichroic mirror 542 that transmits light with a wavelength of 1064 nm and reflects light with a wavelength of 1030 nm are combined.
- An isolator 545 that blocks light in the wavelength 1030 nm band may be provided between the two.
- the ASE photodetector 52 is a high-speed infrared photodetector having a band on the order of MHz or higher, and for example, a sensor using an InGaAs photodiode can be used.
- the detection signal of the signal light detector 51 and the detection signal of the ASE light detector 52 are input to the control unit 25.
- action of the control part 25 based on the detection signal of the signal photodetector 51 is as having explained in full detail in description of 50 A of involuntary oscillation prevention apparatuses of 1st structure form, duplication description is abbreviate
- the operation of the control unit 25 based on the detection signal of the ASE photodetector 52 will be described.
- the control unit 25 outputs a command signal for suppressing power supply to the power breaker 55 when the intensity of the ASE light detected by the ASE light detector 52 exceeds a predetermined ASE reference value, and the current source 26 The pumping power supply to the pump light source 23 is cut off.
- the “ASE reference value” is set based on the intensity of the backward propagation ASE light when the gain of light in the 1030 nm band in the fiber optical amplifier 21 becomes equal to the oscillation threshold. As described above, in the gain distribution of Yb, the gain in the wavelength 1030 nm band is higher than that in the wavelength 1064 nm. If there are any reflectors, the ASE light near 1030 nm emitted by spontaneous emission is reflected by these reflectors, and the feedback level to the amplifier becomes high. As a result, the power level of the ASE light increases.
- Examples of the reflector outside the fiber optical amplifier 21 include dirt on the incident / exit surface of the optical fiber 22 and the incident / exit surface of a wavelength conversion optical element that converts the wavelength of the amplified light emitted from the fiber optical amplifier 21. Is mentioned. In such a case, the return loss of the fiber amplifier is effectively increased and the oscillation threshold is lowered. When the gain at the wavelength of 1030 nm exceeds the oscillation threshold, the fiber optical amplifier 21 oscillates at 1030 nm.
- the “ASE reference value” is set based on the intensity of the backward propagation ASE light when the gain of light in the 1030 nm band in the fiber optical amplifier 21 becomes equal to the oscillation threshold, and is equivalent to the intensity of the backward propagation ASE light at that time.
- it is set to about 1/10 to 1/100.
- the gain in the wavelength 1030 nm band oscillates until the excitation power is substantially cut off by the power breaker 55. It is set based on the time until it becomes equal to the threshold, and is set to be equal to or less than that time, for example, about a fraction.
- the ASE reference value is set and stored in a memory (not shown) provided in the control unit 25.
- FIG. 2 shows the simulation result of the time change of the gain in the wavelength 1030 nm band when the incidence of the signal light Ls suddenly stops when the fiber optical amplifier 21 is excited.
- the inversion distribution rate of Yb is rapidly increased, and the gain g at the wavelength of 1030 nm increases exponentially with time.
- the time from when the signal light Ls is interrupted until oscillation is about 10 ⁇ sec when the return loss of the fiber optical amplifier 21 is ⁇ 50 dB.
- the time until the oscillation starts after exceeding the ASE intensity is as follows: It is about 5 ⁇ sec. Therefore, if the excitation power is substantially cut off within about 2 to 4 ⁇ sec from when the intensity of the backward propagation ASE light becomes equal to or higher than the ASE reference value, the increase of the inversion distribution is suppressed, and the fiber optical amplifier 21 is not oscillated unintentionally. Can be prevented.
- the time until the excitation power is cut off is set and stored in a memory (not shown) provided in the control unit 25.
- the control unit 25 when the detection signal input from the ASE photodetector 52 becomes equal to or higher than the ASE reference value, the control unit 25 outputs a command signal for suppressing power supply to the power breaker 55, and the current source The supply of excitation power from 26 to the pump light source 23 is immediately shut off.
- the time required for the power breaker 55 to suppress the excitation power based on the command signal is less than 1 ⁇ sec. As a result, the excitation power is substantially cut off before the gain at the wavelength of 1030 nm rises to the oscillation threshold, and the fiber optical amplifier 21 can be prevented from unintentionally oscillating.
- the entrance / exit surface of the optical fiber 22 and the input of the wavelength conversion optical element at the subsequent stage are provided. Even when there is dirt on the emission surface or adhesion of dust, or when there is spontaneously emitted return light reflected from an object to be processed or the like, the optical fiber amplifier 21 causes unintentional oscillation and damages its constituent members. Can be prevented in advance. Furthermore, a laser device with high safety and long-term reliability can be provided with a simple configuration in which the fiber coupler 54, the signal light detector 51, and the ASE photodetector are provided on the incident side of the fiber optical amplifier 21.
- the wavelength of the signal light Ls is set to a 1060 nm band and the configuration using the ytterbium-doped fiber optical amplifier (YDFA) as the fiber optical amplifier 21 is exemplified, the wavelength of the signal light may be in another band,
- the fiber optical amplifier may be one doped with another laser medium, such as an erbium-doped fiber optical amplifier (EDFA).
- FIG. 7 shows a schematic configuration diagram of a laser apparatus 3 of a third configuration form to which the present invention is applied.
- the laser device 3 operates the signal light generation unit 10 that generates signal light, the amplification unit 20 that amplifies and emits the signal light generated by the signal light generation unit, and the operations of the signal light generation unit 10 and the amplification unit 20.
- a control device 40 to be controlled.
- the signal light generator 10 is a part that generates the signal light amplified by the amplifier 20, and includes a laser light source 11 such as a semiconductor laser, a bulk solid-state laser, or a fiber laser.
- a laser light source 11 such as a semiconductor laser, a bulk solid-state laser, or a fiber laser.
- FIG. 7 shows a configuration in which a DFB semiconductor laser is used as the laser light source 11 and an external modulator 15 such as an electro-optic modulation element (EOM), an acousto-optic modulation element (AOM), or a semiconductor optical amplifier (SOA) is provided.
- EOM electro-optic modulation element
- AOM acousto-optic modulation element
- SOA semiconductor optical amplifier
- the DFB semiconductor laser can be oscillated with CW and pulse, and can control the pulse waveform of the output light at high speed by controlling the current waveform, and can be narrow band in a predetermined wavelength range by controlling the temperature. It is possible to output single-wavelength pulsed
- pulse light having a wavelength of 1064 nm, a repetition frequency of 2 MHz, and an ON time of about 10 nsec is emitted from the laser light source 11, and 1 to 2 nsec is cut out by the external modulator 15 to output pulse light having a short ON time.
- An example of the configuration will be shown.
- the external modulator 15 is used in this manner, chirp (frequency modulation) generated when the laser light source 11 is directly pulse-oscillated can be suppressed, and pulsed light close to the Fourier limit can be generated.
- the signal light generator 10 can output pulsed signal light having a very narrow bandwidth and high monochromaticity.
- the signal light Ls generated by the signal light generator 10 is incident on the amplifier 20 via the isolator 17.
- the amplification unit 20 is mainly composed of a fiber optical amplifier 21 that amplifies the signal light Ls.
- a fiber optical amplifier that amplifies signal light having a wavelength of 1064 nm an ytterbium-doped fiber optical amplifier (YDFA) having a gain in a wavelength band of 1030 to 1100 nm is preferably used.
- the fiber optical amplifier 21 includes an optical fiber 22 having a core doped with ytterbium (Yb), a pump light source 23 for exciting Yb, a control unit 25 for controlling pumping power supplied to the pump light source 23, and the like.
- a fiber having a double clad structure is used as the optical fiber 22, the signal light Ls output from the laser light output unit 10 is incident on the core via the pump combiner 24, and is output from the pump light source 23. Excitation light having a wavelength of 976 nm is incident on the first cladding.
- the control unit 25 is provided with a current source 26 that generates excitation power and a power breaker 55 that interrupts the supply of the generated excitation power to the pump light source 23 at high speed.
- the optical fiber 22 may be a single-clad fiber, or the amplifier 20 may be configured by connecting a plurality of fiber optical amplifiers in series or in parallel.
- the control device 40 controls the operation of the signal light generating unit 10 and the amplifying unit 20, and the signal light generated by the signal light generating unit 10 and amplified by the amplifying unit 20 to a power of several W to several tens W (for convenience)
- the laser device 3 outputs La (referred to as amplified light).
- the laser device 3 configured in this manner is provided with an involuntary oscillation preventing device 60 (60A) for preventing the fiber optical amplifier 21 from causing unintended oscillation.
- the involuntary oscillation preventing device 60 ⁇ / b> A of the third configuration form includes an ASE photodetector 52 that detects light in the wavelength 1030 nm band emitted from the fiber optical amplifier 21, and a power breaker 55 provided in the control unit 25. Composed.
- the ASE light generated by spontaneous emission in the fiber optical amplifier 21 travels forwardly spontaneously emitted light (Forward ASE light) that travels through the optical fiber 22 to the output side of the amplified light and to the incident side of the signal light. There is backscattered spontaneous emission light (Backward ASE light).
- Forward ASE light forwardly spontaneously emitted light
- Backward ASE light backscattered spontaneous emission light
- an ASE photodetector is provided on the optical path branched from the emission side of the optical fiber 22
- the forward propagation spontaneous emission light is detected, and the ASE photodetector is arranged on the optical path branched from the incident side of the optical fiber 22.
- it is provided it is possible to detect backward propagation spontaneous emission light.
- a dichroic mirror 56 that transmits light having a wavelength of 1064 nm and reflects light having a wavelength of 1030 nm is provided between the laser light source 11 and the fiber optical amplifier 21, and the backward propagation reflected by the dichroic mirror 56 is provided.
- a configuration in which spontaneous emission light is detected by the ASE photodetector 52 is shown. Note that a WDM coupler may be used in place of the dichroic mirror 56.
- the ASE photodetector 52 is a high-speed infrared photodetector having a band on the order of MHz or higher, and for example, a sensor using an InGaAs photodiode can be used.
- a detection signal from the ASE photodetector 52 is input to the control unit 25.
- the control unit 25 outputs a command signal for suppressing power supply to the power breaker 55 when the intensity of the ASE light detected by the ASE light detector 52 exceeds a predetermined ASE reference value, and the current source 26 Is substantially cut off from the supply of excitation power to the pump light source 23.
- the “ASE reference value” is set based on the intensity of the backward propagation ASE light when the gain of light in the 1030 nm band in the fiber optical amplifier 21 becomes equal to the oscillation threshold. As described above, in the gain distribution of Yb, the gain is higher in the wavelength 1030 nm band than in the wavelength 1064 nm. Therefore, when the fiber light amplifier 21 is pumped and the signal light Ls is not incident, If there is any reflector outside, ASE light near 1030 nm emitted by spontaneous emission is reflected by these reflectors, and the feedback level to the amplifier becomes high. As a result, the power level of the ASE light increases.
- Examples of the reflector outside the fiber optical amplifier 21 include dirt on the incident / exit surface of the optical fiber 22 and the incident / exit surface of a wavelength conversion optical element that converts the wavelength of the amplified light emitted from the fiber optical amplifier 21. Is mentioned. In such a case, the return loss of the fiber amplifier is effectively increased, and the oscillation threshold is lowered. When the gain at the wavelength of 1030 nm exceeds the oscillation threshold (when the one-way gain at the wavelength of 1030 nm exceeds the return loss of the fiber optical amplifier 21), the fiber optical amplifier 21 starts laser oscillation at 1030 nm.
- the “ASE reference value” is set based on the intensity of the backward propagation ASE light when the gain of light in the 1030 nm band in the fiber optical amplifier 21 becomes equal to the oscillation threshold, and is equivalent to the intensity of the backward propagation ASE light at that time.
- it is set to about 1/10 to 1/100.
- the gain in the wavelength 1030 nm band oscillates until the excitation power is substantially cut off by the power breaker 55. It is set based on the time until it becomes equal to the threshold, and is set to be equal to or less than that time, for example, immediately to within several tenths.
- the ASE reference value is set and stored in a memory (not shown) provided in the control unit 25.
- the signal light Ls is incident on the fiber optical amplifier 21 while the power of the signal light Ls incident on the fiber optical amplifier 21 is 0.5 W and the power of the pumping light from the pump light source 23 is 120 W.
- FIG. 8 shows the simulation result of the time change of the gain in the wavelength 1030 nm band when the signal is suddenly interrupted.
- the horizontal axis represents the elapsed time from when the incidence of the signal light Ls was interrupted, and the vertical axis represents the gain of light having a wavelength of 1030 nm.
- the fiber optical amplifier 21 had a length of 3 m, a core diameter of 25 ⁇ m, a cladding diameter of 250 ⁇ m, and the concentration of Yb added to the core was 6.9 ⁇ 10 25 / m 3 .
- the inversion distribution rate of Yb increases rapidly, and the gain g at a wavelength of 1030 nm increases exponentially with time.
- the oscillation threshold depends on the amount of reflected light remaining in the fiber optical amplifier 21 and varies depending on the configuration of the fiber optical amplifier. Assuming that the return loss of the fiber optical amplifier 21 is ⁇ 50 dB, oscillation occurs at 1030 nm when the one-way gain exceeds 50 dB. From FIG. 8, it can be seen that the oscillation starts in about 10 ⁇ sec from the time when the signal light Ls is interrupted.
- the time until the one-way gain of the fiber optical amplifier 21 exceeds the return loss is almost inversely proportional to the power of the pumping light. Therefore, if the pumping power of the pumping light is large, oscillation occurs in a shorter time than the above, and the pumping power is small. It takes longer time to oscillate.
- the time until the oscillation starts after exceeding the ASE intensity is as follows: It is about 5 ⁇ sec. Therefore, if the excitation power is substantially cut off within about 2 to 4 ⁇ sec from when the intensity of the backward propagation ASE light becomes equal to or higher than the ASE reference value, the increase of the inversion distribution is suppressed, and the fiber optical amplifier 21 is not oscillated unintentionally. Can be prevented.
- the control unit 25 when the detection signal input from the ASE photodetector 52 becomes equal to or higher than the ASE reference value, the control unit 25 outputs a command signal for suppressing power supply to the power breaker 55, and the current source The supply of excitation power from 26 to the pump light source 23 is immediately suppressed.
- the time during which the power breaker 55 suppresses the excitation power based on the command signal is less than 1 ⁇ sec (the excitation power suppression time will be described later). As a result, the excitation power is suppressed before the gain at the wavelength of 1030 nm rises to the oscillation threshold, and unintended oscillation can be suppressed.
- the time until the excitation power is cut off is set and stored in a memory (not shown) provided in the control unit 25.
- the laser device 3 provided with the involuntary oscillation preventing device 60A there is a case where dirt or dust adheres to the incident / exit surface of the optical fiber 22 or the incident / exit surface of the wavelength conversion optical element at the subsequent stage, or from a processing object. Even when there is reflected spontaneously emitted return light, it is possible to prevent the constituent members from being damaged due to unintended oscillation of the fiber optical amplifier 21.
- FIG. 9 shows a schematic configuration of the entire laser apparatus 4 including the involuntary oscillation preventing apparatus 60B.
- the same components as those of the laser device 3 are denoted by the same reference numerals, and redundant description is omitted.
- the involuntary oscillation preventing device 60B according to the fourth configuration form includes a signal light detector 51 that detects the signal light Ls propagating to the fiber optical amplifier 21 in addition to the involuntary oscillation preventing device 60A according to the third configuration form. Is done.
- a 4-port 2 ⁇ 2 melt-stretching optical fiber coupler 54 as shown in FIG. 10 is provided between the laser light source 11 and the fiber optical amplifier 21, and each port is provided.
- the signal light Ls, the fiber optical amplifier 21, the signal light detector 51, and the ASE light detector 52 described above are combined.
- the optical fiber coupler 54 has a branching ratio of 99: 1, for example, branches 1% of the signal light Ls incident from the signal light generating unit 10 side to the signal light detector 51, and is generated by the fiber optical amplifier 21 to be incident side. 1% of the back-propagating spontaneously emitted light that travels to the ASE photodetector 52 can be branched.
- FIG. 10 illustrates a configuration provided with a bandpass filter BPF that transmits only backward propagation spontaneous emission light having a wavelength of 1030 nm.
- a wavelength-selective partial reflection mirror that totally reflects light of a wavelength of 1030 nm band and transmits 99% of light having a wavelength of 1064 nm and reflects 1% is used. Reflected light having a wavelength of 1064 nm incident and reflected from the light generating unit 10 side is incident on the signal light detector 51, and ASE light having a wavelength of 1030 nm band incident and reflected from the amplifying unit 20 side is reflected on the ASE photodetector 52. You may comprise so that it may inject into. Alternatively, as shown in FIG.
- a partial reflection mirror 541 that transmits 99% of light with a wavelength of 1064 nm (1% reflection) and a dichroic mirror 542 that transmits light with a wavelength of 1064 nm and reflects light with a wavelength of 1030 nm are combined.
- An isolator 545 that suppresses light in the wavelength 1030 nm band may be provided between the two.
- the signal light detector 51 is a high-speed infrared light sensor having a band on the order of MHz or higher, and for example, a sensor using an InGaAs photodiode can be used.
- the detection signal of the signal light detector 51 and the detection signal of the ASE light detector 52 are input to the control unit 25.
- action of the control part 25 based on the detection signal of the ASE photodetector 52 is as having explained in full detail in description of the involuntary oscillation prevention apparatus 50A of a 1st structure form, duplication description is abbreviate
- the operation of the control unit 25 based on the detection signal of the signal light detector 51 will be described.
- the control unit 25 When the intensity of the signal light Ls detected by the signal light detector 51 is equal to or lower than a predetermined signal reference value, the control unit 25 outputs a command signal for suppressing power supply to the power breaker 55, and a current source The supply of excitation power from 26 to the pump light source 23 is cut off.
- the “signal reference value” is set based on the magnitude of the gain in the wavelength 1030 nm band that increases when the intensity of the signal light Ls incident on the optical fiber 22 decreases when the fiber optical amplifier 21 is excited. Is done.
- the inversion distribution ratio of Yb increases with the decrease in the signal light intensity, and the gain distribution as a whole gains. rise to a high state. At this time, in the gain distribution, the gain is higher in the wavelength 1030 nm band than in the wavelength 1064 nm. As a result, when the increased gain of the wavelength 1030 nm exceeds the oscillation threshold, the fiber optical amplifier 21 starts laser oscillation at 1030 nm. .
- the “signal reference value” is set based on the intensity of the signal light when the gain in the 1030 nm band becomes equal to the oscillation threshold in the gain distribution that increases as the intensity of the signal light Ls incident on the fiber optical amplifier 21 decreases. The For example, it is set equal to or greater than the intensity of the signal light Ls or a value added with a predetermined margin.
- the signal reference value is set and stored in a memory (not shown) provided in the control unit 25.
- the time from when the intensity of the signal light Ls detected by the signal light detector 51 becomes equal to or lower than the signal reference value until the excitation power is substantially cut off by the power breaker 55 is a signal incident on the fiber optical amplifier 21.
- the gain distribution is set based on the time until the gain in the 1030 nm band becomes equal to the oscillation threshold, and is set equal to or less than that time, for example, about a fraction of that time. Is done.
- the set time is set and stored in a memory (not shown) provided in the control unit 25.
- FIG. 8 shows a simulation result of the time change of the gain in the wavelength 1030 nm band when the input of the signal light Ls suddenly stops when the fiber optical amplifier 21 is excited.
- the inversion distribution ratio of Yb is rapidly increased, and the gain g at the wavelength of 1030 nm increases exponentially with time.
- the time from when the signal light Ls is interrupted until oscillation is about 10 ⁇ sec when the return loss of the fiber optical amplifier 21 is ⁇ 50 dB.
- the time until the one-way gain of the fiber optical amplifier 21 exceeds the return loss is almost inversely proportional to the power of the pumping light, when the power of the pumping light is larger, oscillation occurs in a shorter time, and When the power is smaller, oscillation takes longer time. If the excitation power is substantially cut off within about 6 to 8 ⁇ sec from when the incident power of the signal light Ls is greatly reduced, the increase of the inversion distribution can be suppressed, and unintentional oscillation of the fiber optical amplifier 21 can be suppressed. .
- the control unit 25 when the detection signal input from the signal light detector 51 becomes equal to or less than the signal reference value, the control unit 25 outputs a command signal for suppressing power supply to the power breaker 55.
- the supply of excitation power from the current source 26 to the pump light source 23 is suppressed within a few ⁇ sec.
- the signal light Ls is 1 to 3 ⁇ se corresponding to 2 to 6 light pulses (for example, 2 ⁇ se corresponding to 4 pulses).
- a configuration in which supply of excitation power to the pump light source 23 is immediately suppressed when it is not detected is exemplified.
- FIG. 12 shows the experimental results of observing the excitation current interruption state by the involuntary oscillation prevention device.
- the horizontal axis represents time (1 ⁇ sec / div)
- the vertical axis represents the excitation power and the light intensity of the signal light Ls.
- the excitation power to the pump light source 23 is cut off after confirming that it has been interrupted for 2 ⁇ s corresponding to four light pulses, and the time required for the power breaker 55 to cut off the excitation power. Is less than 1 ⁇ sec.
- the pump power is increased before the gain of the wavelength 1030 nm rises to the oscillation threshold. Are substantially cut off, and the fiber optical amplifier 21 can be prevented from causing unintended oscillation.
- the signal light Ls is interrupted due to breakage or disconnection of the external modulator 15, entry of foreign matter on the optical path between the laser light source 11 and the fiber optical amplifier 21, or disconnection of the introduction portion of the optical fiber 22. Even in such a case, it is possible to prevent the fiber optical amplifier 21 from causing unintended oscillation, and as a result, it is possible to prevent the constituent members from being damaged. Furthermore, it is possible to provide a laser device with high safety and long-term reliability with a simple configuration in which the fiber coupler 54, the signal light detector 51, and the ASE photodetector are provided on the incident side of the fiber optical amplifier 21.
- the wavelength of the signal light Ls is set to a 1060 nm band and the configuration using the ytterbium-doped fiber optical amplifier (YDFA) as the fiber optical amplifier 21 is exemplified, the wavelength of the signal light may be in another band,
- the fiber optical amplifier may be one doped with another laser medium, such as an erbium-doped fiber optical amplifier (EDFA).
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Abstract
Description
以下、本発明を実施するための第1の形態について、図面を参照しながら説明する。図1に本発明の第1の態様における、第1構成形態のレーザ装置1の概要構成図を示す。レーザ装置1は、信号光を発生する信号光発生部10と、信号光発生部により発生された信号光を増幅して出射する増幅部20と、信号光発生部10及び増幅部20の作動を制御する制御装置40とを備えて構成される。
次に、本発明を実施するための第2の形態について、図7を参照しながら説明する。図7に本発明を適用した第3構成形態のレーザ装置3の概要構成図を示す。レーザ装置3は、信号光を発生する信号光発生部10と、信号光発生部により発生された信号光を増幅して出射する増幅部20と、信号光発生部10及び増幅部20の作動を制御する制御装置40とを備えて構成される。
日本国出願2011年第009122号(2011年1月19日)
日本国出願2011年第009126号(2011年1月19日)
Claims (17)
- レーザ装置であって、
信号光を含む波長帯域で利得を有し信号光を増幅して出射するファイバ光増幅器と、
前記ファイバ光増幅器を励起するための励起電力を制御する制御部と、
前記ファイバ光増幅器に伝播される信号光を検出する信号光検出器か、または、前記ファイバ光増幅器から出射する、前記ファイバ光増幅器の利得分布における前記信号光よりも利得が高い波長の光を検出するASE光検出器を備え、
前記信号光検出器により検出された信号光の強度が所定の信号基準値以下となったときか、または、前記ASE光検出器により検出された自然放出光の強度が所定のASE基準値以上となったときに、前記制御部は、前記ファイバ光増幅器を励起するための前記励起電力を抑制するレーザ装置。 - レーザ装置であって、
信号光を含む波長帯域で利得を有し信号光を増幅して出射するファイバ光増幅器と、
前記ファイバ光増幅器に伝播される信号光を検出する信号光検出器と、
前記ファイバ光増幅器を励起するための励起電力を制御する制御部とを備え、
前記制御部は、前記信号光検出器により検出された信号光の強度が所定の信号基準値以下となったときに、前記ファイバ光増幅器を励起するための前記励起電力を抑制するレーザ装置。 - 請求項1または2に記載のレーザ装置において前記所定の信号基準値は、前記ファイバ光増幅器に伝播される信号光の強度低下に伴って上昇する前記ファイバ光増幅器の利得分布における、前記信号光よりも利得が高い波長の光の利得が、発振閾値と等しくなるときの前記信号光の強度に基づいて設定されるレーザ装置。
- 請求項1~3のいずれか一項に記載のレーザ装置において、前記信号光検出器により検出された信号光の強度が前記所定の信号基準値以下となったのち前記励起電力が抑制されるまでの時間は、前記ファイバ光増幅器に入射する信号光の強度低下に伴って上昇する前記ファイバ光増幅器の利得分布における、前記信号光よりも利得が高い波長の光の利得が、発振閾値と等しくなるまでの時間に基づいて設定されるレーザ装置。
- 請求項1~4のいずれか一項に記載のレーザ装置において、前記ファイバ光増幅器から出射する、前記ファイバ光増幅器の利得分布における前記信号光よりも利得が高い波長の光を検出するASE光検出器を備え、前記制御部は、前記ASE光検出器により検出された自然放出光の強度が所定のASE基準値以上となったときに、前記励起電力を抑制するレーザ装置。
- 請求項5に記載のレーザ装置において、前記所定のASE基準値は、前記ファイバ光増幅器における前記信号光よりも利得が高い波長の光の利得が、発振閾値と等しくなるときの自然放出光の強度に基づいて設定されるレーザ装置。
- 請求項5または6に記載のレーザ装置において、前記ASE光検出器により検出された自然放出光の強度が前記所定のASE基準値以上となったのち前記励起電力が抑制されるまでの時間は、前記ファイバ光増幅器における前記信号光よりも利得が高い波長の光の利得が、発振閾値と等しくなるまでの時間に基づいて設定されるレーザ装置。
- 請求項5~7のいずれか一項に記載のレーザ装置において、前記ASE光検出器は前記ファイバ光増幅器における信号光の入射側に設けられ、前記ファイバ光増幅器を入射側に向かう後方伝搬自然放出光を検出するレーザ装置。
- レーザ装置であって、
信号光を含む波長帯域で利得を有し信号光を増幅して出射するファイバ光増幅器と、
前記ファイバ光増幅器から出射する、前記ファイバ光増幅器の利得分布における前記信号光よりも利得が高い波長の光を検出するASE光検出器と、
前記ファイバ光増幅器の励起電力を制御する制御部とを備え、
前記制御部は、前記ASE光検出器により検出された自然放出光の強度が所定のASE基準値以上となったときに、前記ファイバ光増幅器を励起するための前記励起電力を抑制するレーザ装置。 - 請求項1または9に記載のレーザ装置において、前記所定のASE基準値は、前記ファイバ光増幅器における前記信号光よりも利得が高い波長の光の利得が、発振閾値と等しくなるときの自然放出光の強度に基づいて設定されるレーザ装置。
- 請求項1、9および10のいずれか一項に記載のレーザ装置において、前記ASE光検出器により検出された自然放出光の強度が前記所定のASE基準値以上となったのち前記励起電力が抑制されるまでの時間は、前記ファイバ光増幅器における前記信号光よりも利得が高い波長の光の利得が、発振閾値と等しくなるまでの時間に基づいて設定されるレーザ装置。
- 請求項1および9~11のいずれか一項に記載のレーザ装置において、前記ASE光検出器は前記ファイバ光増幅器における信号光の入射側に設けられ、前記ファイバ光増幅器を入射側に向かう後方伝搬自然放出光を検出するレーザ装置。
- 請求項1および9~12のいずれか一項に記載のレーザ装置において、前記ファイバ光増幅器に入射する信号光を検出する信号光検出器を備え、前記制御部は、前記信号光検出器により検出された信号光の強度が所定の信号基準値以下となったときに、前記励起電力を抑制するように構成されるレーザ装置。
- 請求項13に記載のレーザ装置において、前記所定の信号基準値は、前記ファイバ光増幅器に入射する信号光の強度低下に伴って上昇する前記ファイバ光増幅器の利得分布における、前記信号光よりも利得が高い波長の光の利得が、発振閾値と等しくなるときの前記信号光の強度に基づいて設定されるレーザ装置。
- 請求項13または14に記載のレーザ装置において、前記信号光検出器により検出された信号光の強度が前記所定の信号基準値以下となったのち前記励起電力が抑制されるまでの時間は、前記ファイバ光増幅器に入射する信号光の強度低下に伴って上昇する前記ファイバ光増幅器の利得分布における、前記信号光よりも利得が高い波長の光の利得が、発振閾値と等しくなるまでの時間に基づいて設定されるレーザ装置。
- 請求項5~8および12~15に記載のいずれか一項に記載のレーザ装置において、前記ファイバ光増幅器の入射側に4つのポートを有する光ファイバカプラが設けられ、前記4つのポートに、前記信号光、前記ファイバ光増幅器、前記信号光検出器、及び前記ASE光検出器が接続されて構成されるレーザ装置。
- 請求項1~16のいずれか一項に記載のレーザ装置において、前記ファイバ光増幅器はイットリビウムをレーザ媒質とするイットリビウム・ドープ・ファイバ光増幅器であり、前記信号光の波長は1.06μm帯であるレーザ装置。
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/980,757 US8988768B2 (en) | 2011-01-19 | 2012-01-18 | Laser device |
JP2012553752A JP5794237B2 (ja) | 2011-01-19 | 2012-01-18 | レーザ装置 |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2011009122 | 2011-01-19 | ||
JP2011-009122 | 2011-01-19 | ||
JP2011-009126 | 2011-01-19 | ||
JP2011009126 | 2011-01-19 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2012099166A1 true WO2012099166A1 (ja) | 2012-07-26 |
Family
ID=46515788
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2012/050963 WO2012099166A1 (ja) | 2011-01-19 | 2012-01-18 | レーザ装置 |
Country Status (4)
Country | Link |
---|---|
US (1) | US8988768B2 (ja) |
JP (1) | JP5794237B2 (ja) |
TW (1) | TWI547048B (ja) |
WO (1) | WO2012099166A1 (ja) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI583347B (zh) * | 2013-09-14 | 2017-05-21 | 明達醫學科技股份有限公司 | 光學裝置之光源模組及其運作方法 |
JP2015169524A (ja) * | 2014-03-06 | 2015-09-28 | 株式会社アドバンテスト | 試験装置、キャリブレーションデバイス、キャリブレーション方法、および試験方法 |
US9583907B2 (en) * | 2014-04-11 | 2017-02-28 | Raytheon Company | System and method for generating high energy optical pulses with arbitrary waveform |
JP7160680B2 (ja) * | 2016-04-21 | 2022-10-25 | 日本電気株式会社 | 光増幅器、光ネットワーク、及び増幅方法 |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0468830A (ja) * | 1990-07-06 | 1992-03-04 | Fujitsu Ltd | 光増幅装置の制御方法及び光増幅装置 |
JPH05130043A (ja) * | 1991-03-29 | 1993-05-25 | Cavi Pirelli Spa | 保護装置を備えた光増幅器を含む光フアイバ通信回線 |
JPH05206557A (ja) * | 1991-05-20 | 1993-08-13 | Furukawa Electric Co Ltd:The | 光増幅システム |
JPH06120899A (ja) * | 1992-05-09 | 1994-04-28 | Alcatel Nv | 巨大パルスを避けるためのモニタ装置を備えた光通信システム |
JPH0865249A (ja) * | 1994-08-26 | 1996-03-08 | Fujitsu Ltd | 光サージの発生を抑圧した光増幅器 |
JPH1051395A (ja) * | 1996-08-01 | 1998-02-20 | Oki Electric Ind Co Ltd | 光ファイバ増幅装置 |
JP2007294931A (ja) * | 2006-03-31 | 2007-11-08 | Sumitomo Electric Ind Ltd | 光ファイバ増幅モジュール |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA2068975C (en) | 1991-05-20 | 2002-03-26 | Kazunori Nakamura | Optical amplification system |
JPH0837497A (ja) * | 1994-05-20 | 1996-02-06 | Fujitsu Ltd | 光増幅器及び光送信装置 |
JP2800715B2 (ja) * | 1995-05-12 | 1998-09-21 | 日本電気株式会社 | 光ファイバ増幅器 |
JPH09321701A (ja) * | 1996-05-31 | 1997-12-12 | Fujitsu Ltd | 光通信システム及び光増幅器 |
JP4232130B2 (ja) | 1998-03-11 | 2009-03-04 | 株式会社ニコン | レーザ装置並びにこのレーザ装置を用いた光照射装置および露光方法 |
JP2002050815A (ja) | 2000-05-24 | 2002-02-15 | Nikon Corp | 光源装置、露光装置、露光装置の製造方法、及びデバイス製造方法 |
JP2000216458A (ja) * | 2000-01-01 | 2000-08-04 | Mitsubishi Electric Corp | 光ファイバ増幅器の増幅特性測定装置 |
JP2001196670A (ja) * | 2000-01-12 | 2001-07-19 | Oki Electric Ind Co Ltd | 光増幅器 |
US8098424B2 (en) | 2006-03-31 | 2012-01-17 | Sumitomo Electric Industries, Ltd. | Optical fiber amplifying module |
US7940453B2 (en) * | 2006-08-07 | 2011-05-10 | Pyrophotonics Lasers Inc. | Fiber amplifiers and fiber lasers with reduced out-of-band gain |
JP2009176944A (ja) * | 2008-01-24 | 2009-08-06 | Mitsubishi Electric Corp | ファイバーレーザ装置及び制御方法 |
-
2012
- 2012-01-18 WO PCT/JP2012/050963 patent/WO2012099166A1/ja active Application Filing
- 2012-01-18 US US13/980,757 patent/US8988768B2/en active Active
- 2012-01-18 JP JP2012553752A patent/JP5794237B2/ja active Active
- 2012-01-19 TW TW101102162A patent/TWI547048B/zh active
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0468830A (ja) * | 1990-07-06 | 1992-03-04 | Fujitsu Ltd | 光増幅装置の制御方法及び光増幅装置 |
JPH05130043A (ja) * | 1991-03-29 | 1993-05-25 | Cavi Pirelli Spa | 保護装置を備えた光増幅器を含む光フアイバ通信回線 |
JPH05206557A (ja) * | 1991-05-20 | 1993-08-13 | Furukawa Electric Co Ltd:The | 光増幅システム |
JPH06120899A (ja) * | 1992-05-09 | 1994-04-28 | Alcatel Nv | 巨大パルスを避けるためのモニタ装置を備えた光通信システム |
JPH0865249A (ja) * | 1994-08-26 | 1996-03-08 | Fujitsu Ltd | 光サージの発生を抑圧した光増幅器 |
JPH1051395A (ja) * | 1996-08-01 | 1998-02-20 | Oki Electric Ind Co Ltd | 光ファイバ増幅装置 |
JP2007294931A (ja) * | 2006-03-31 | 2007-11-08 | Sumitomo Electric Ind Ltd | 光ファイバ増幅モジュール |
Also Published As
Publication number | Publication date |
---|---|
TW201240251A (en) | 2012-10-01 |
JP5794237B2 (ja) | 2015-10-14 |
US8988768B2 (en) | 2015-03-24 |
US20140036349A1 (en) | 2014-02-06 |
JPWO2012099166A1 (ja) | 2014-06-30 |
TWI547048B (zh) | 2016-08-21 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4699131B2 (ja) | 光ファイバレーザ、光ファイバ増幅器、mopa方式光ファイバレーザ | |
JP5185929B2 (ja) | ファイバレーザ | |
US7885298B2 (en) | Method and apparatus for producing arbitrary pulsetrains from a harmonic fiber laser | |
US9397465B2 (en) | Fiber laser device | |
US7457329B2 (en) | Method and system for a high power low-coherence pulsed light source | |
JP5623706B2 (ja) | レーザ光源 | |
CN111373614B (zh) | 用于提供光学辐射的装置 | |
JP5794237B2 (ja) | レーザ装置 | |
US8369004B2 (en) | MOPA light source | |
JPH0818138A (ja) | 光増幅器 | |
JP2014033098A (ja) | ファイバレーザ装置 | |
JP2012178478A (ja) | 高速光増幅器 | |
JP4910328B2 (ja) | 光増幅装置およびレーザ光源装置 | |
US20240022038A1 (en) | Laser amplification with passive peak-power filter | |
JP5049412B2 (ja) | レーザ装置 | |
JP2001358392A (ja) | 安全光移行制御方法および光ファイバ増幅器 | |
JP5662770B2 (ja) | ファイバレーザ装置 | |
US10483711B2 (en) | Method and apparatus for providing amplified radiation | |
JPH09321373A (ja) | 光信号監視回路および光増幅器 | |
JP5398804B2 (ja) | ファイバレーザ装置 | |
JP2013055283A (ja) | 高パワーパルス光発生装置 | |
JP2018174206A (ja) | レーザ装置 | |
JP2012044224A (ja) | 光増幅装置およびレーザ光源装置 | |
US20220052503A1 (en) | Fiber Amplifier Having Dual Output Laser Diode | |
JP6257658B2 (ja) | ファイバレーザ装置 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 12736137 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2012553752 Country of ref document: JP Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 13980757 Country of ref document: US |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 12736137 Country of ref document: EP Kind code of ref document: A1 |