JP2012165010A - Laser light source - Google Patents

Abstract

A laser light source capable of stabilizing the energy of an output pulse laser beam is provided.
A laser light source 1 includes a control unit 10, an optical amplifying fiber 11, an excitation light source 12, an optical switch 13, a drive circuit 14, a monitor unit 15, an output light power adjuster 16, a total reflection mirror 17, a lens 18A, A lens 18B and a dichroic mirror 19 are provided. When the optical path between the first port 13a and the third port 13c of the optical switch 13 is in a state where light can pass, the end face 11a of the optical amplifying fiber 11 and the total reflection mirror 17 constitute a laser resonator. To do. Based on the optical power monitored by the monitor unit 15 when the optical path between the second port 13b and the third port 13c of the optical switch 13 is in a light-passable state, the control unit 10 Stabilization control is performed on the peak power or energy of the laser beam that is output when the optical path between the first port 13a and the third port 13c is in a light-passable state.
[Selection] Figure 1

Description

  The present invention relates to a laser light source that pulsates laser light.

  A laser light source that pulsates laser light includes a laser resonator in which a laser medium that emits light when supplied with excitation energy is disposed on a resonance optical path, and a Q switch that modulates the resonator loss of the laser resonator And excitation means for continuously supplying excitation energy to the laser medium.

  In this laser light source, when the cavity loss of the laser resonator is set to a large value by the Q switch means, the inversion distribution of the laser medium is enhanced by the excitation energy supply by the excitation means, and then the laser is turned by the Q switch means. When the resonator loss of the resonator is set to a small value, stimulated emission occurs in a short time in the laser medium disposed on the resonance optical path of the laser resonator. This stimulated emission light is output as laser light from the laser resonator to the outside.

  Such a laser light source is capable of outputting pulse laser light having a high peak power, and thus is widely used for electronic / mechanical processing applications, medical laser scalpels, measurement applications such as length measurement, and the like. For example, in processing applications, the laser light irradiated for processing is required to have an output power stability of about 5% p-p. However, the stability of the pulse output is not always good in the conventional laser light source.

  Note that which of the energy and power of the pulsed laser light is important depends on the type of processing such as welding / cutting and the type of processing target. As a general tendency, the energy of pulsed laser light is important when performing conventional thermal processing. On the other hand, in processing that requires a femtosecond pulse such as ablation, the power density (W / cm 2) of the pulse laser beam is also an important factor, and the efficiency of absorption of the pulse laser beam at a power density exceeding 1015 W / cm 2 is increased. Improve dramatically.

  Patent Documents 1 and 2 disclose laser light sources intended to stabilize the energy or power of output pulse laser light. In the laser light sources disclosed in these documents, a part of the pulsed laser beam outputted from the laser resonator to the outside is branched and extracted, and the power of the branched and extracted pulsed laser beam is monitored. Based on the monitoring result, feedback control is performed so that the energy or power of the output pulse laser beam is stabilized.

Japanese Patent No. 3331726 JP 2001-332791 A

  However, even with a laser light source that performs feedback control as disclosed in Patent Documents 1 and 2, the energy or power of the output pulse laser beam is unstable.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a laser light source capable of stabilizing the energy or power of an output pulse laser beam.

  A laser light source according to the present invention is a laser light source that pulse-oscillates laser light, and (1) a laser resonator in which a laser medium that generates emitted light when supplied with excitation energy is disposed on a resonant optical path; (2) Excitation means for continuously supplying excitation energy to the laser medium, and (3) In response to the excitation energy supply by the excitation means, the power of the light extracted from the middle of the optical path in the resonator is A monitor unit for monitoring; (4) Q-switch means for modulating the resonator loss of the laser resonator and switching the optical path to be output to the monitor unit according to the resonator loss; and (5) laser light output from the laser resonator. An output optical power regulator for amplifying or attenuating the emission, and (6) emission monitored by the monitor unit in a state where the resonator loss of the laser resonator is set to the first predetermined loss for non-oscillation of the high output pulse Based on optical power And controlling the physical parameters in the resonator so as to stabilize the energy of the laser light pulse output when the resonator loss of the laser resonator is set to the second predetermined loss for high-power pulse oscillation. And a controller for controlling the gain or loss of the output light power adjuster so as to stabilize the peak power of the output laser light pulse.

  In the laser light source according to the present invention, the control unit feedback-controls the physical parameter in the resonator that affects the output characteristics of the laser light source based on the emitted light power monitored by the monitor unit, so that the output of the laser light to be output It is preferred to stabilize the peak power or energy. Here, the physical parameters include excitation energy, resonator oscillation wavelength, resonator reflectivity, and Q switch means loss (Q switch means branching ratio). In this case, the peak power or energy of the output laser light is controlled by feedback control of the physical parameters in the resonator that affect the output characteristics of the laser light source based on the emitted light power monitored by the monitor unit. Stabilized.

  The laser light source according to the present invention has Q switch means, and the Q switch means has a pair of ports constituting part of the laser resonator, and one of the remaining ports is part of the optical power in the laser resonator. It is preferably used for monitoring. The optical switch preferably uses an acoustooptic effect, preferably uses an electrooptic effect, and preferably uses a piezooptic effect. .

  In the laser light source according to the present invention, the control unit outputs the control light based on the emission light power monitored by the last monitor unit in the period in which the resonator loss is set to the first predetermined loss. It is preferable to stabilize the peak power or energy of the laser light. In this case, the peak power or energy of the output laser light is further stabilized.

  According to the present invention, the energy or power of the output pulse laser beam can be stabilized.

It is a block diagram of the laser light source 1 which concerns on 1st Embodiment. It is a figure which shows the output pulse waveform of the laser light source 1 in case the stabilization control by the control part 10 is not performed. It is a figure which expands and shows the output light waveform of the time slot | zones other than the time of the pulse output of the laser light source 1 when not performing stabilization control by the control part 10. FIG. It is a graph which shows the peak power and energy per pulse of each output pulse of the laser light source 1 when the stabilization control by the control part 10 is not performed. It is a figure which shows the relationship between the optical power value monitored by the monitor part 15, and the energy value of output pulse light just before the resonator loss of the laser resonator of the laser light source 1 becomes the minimum. It is a figure which shows the relationship between the optical power value monitored by the monitor part 15, and the peak power value of output pulse light just before the resonator loss of the laser resonator of the laser light source 1 becomes the minimum. It is a figure which shows the relationship between the optical power average value monitored by the monitor part 15, and the energy value of output pulse light in the period when the resonator loss of the laser resonator of the laser light source 1 is not the minimum. It is a figure which shows the relationship between the optical power average value monitored by the monitor part 15, and the peak power value of output pulse light in the period when the resonator loss of the laser resonator of the laser light source 1 is not the minimum. It is a block diagram of the laser light source 2 which concerns on 2nd Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  (First embodiment)

  First, a first embodiment of a laser light source according to the present invention will be described. FIG. 1 is a configuration diagram of a laser light source 1 according to the first embodiment. The laser light source 1 shown in this figure includes a control unit 10, an optical amplifying fiber 11, an excitation light source 12, an optical switch 13, a drive circuit 14, a monitor unit 15, an output light power adjuster 16, a total reflection mirror 17, and a lens 18A. The lens 18B and the dichroic mirror 19 are provided.

  The optical amplifying fiber 11 is an optical fiber in which a fluorescent element is added to an optical waveguide region, and emits fluorescence from the fluorescent element when excitation light having a wavelength capable of exciting the fluorescent element is supplied. . This fluorescent element is preferably a rare earth element, and among them, Er element, Yb element and the like are preferable. One end surface 11a of the optical amplifying fiber 11 is a vertical cleavage surface, and the other end surface 11b of the optical amplifying fiber 11 is coated with a non-reflective coating.

  The excitation light source 12 continuously outputs excitation light for exciting the fluorescent element added to the light amplifying fiber 11. The excitation light source 12 preferably includes a laser diode. The dichroic mirror 19 receives the excitation light output from the excitation light source 12, and reflects the excitation light to the lens 18A. The lens 18 </ b> A receives the excitation light that has arrived from the dichroic mirror 19, condenses the excitation light on the end face 11 a of the optical amplifying fiber 11 and makes it incident. The lens 18 </ b> A receives light emitted from the fluorescent element of the light amplifying fiber 11 and output from the end face 11 a, collimates the light, and outputs the collimated light to the dichroic mirror 19. The dichroic mirror 19 inputs light that has arrived from the lens 18A and transmits this light.

  The optical switch 13 has a first port 13a, a second port 13b, and a third port 13c. The first port 13a is optically connected to the total reflection mirror 17, the second port 13b is optically connected to the monitor unit 15, and the third port 13c is an end face 11b of the optical amplifying fiber via the lens 18B. And optically connected. The optical switch 13 operates by being driven by the drive circuit 14, and is one of a first optical path between the first port 13a and the third port 13c and a second optical path between the second port 13b and the third port 13c. However, the light can be selectively transmitted.

  The optical switch 13 may use an acousto-optic effect, may use an electro-optic effect, or may use a piezo-optical effect (for example, manufactured by CVI). ). When the optical switch 13 uses the acousto-optic effect, when the high frequency voltage is not applied to the optical switch 13, the light output from the end face 11b of the optical amplifying fiber 11 is not diffracted and is monitored 15 When a high frequency voltage is applied to the optical switch 13, the light output from the end face 11 b of the optical amplifying fiber 11 is diffracted and output to the total reflection mirror 17. On the contrary, when a high frequency voltage is not applied to the optical switch 13, the light output from the end face 11b of the optical amplifying fiber 11 is output to the total reflection mirror 17 without being diffracted, and the optical switch When a high-frequency voltage is applied to 13, the light output from the end face 11 b of the optical amplifying fiber 11 may be diffracted and output to the monitor unit 15.

  The lens 18 </ b> B receives light output from the end face 11 b of the optical amplifying fiber 11 and inputs this light to the third port 13 c of the optical switch 13. The lens 18 </ b> B inputs light output from the third port 13 c of the optical switch 13 and inputs this light to the end face 11 b of the optical amplifying fiber 11. The total reflection mirror 17 totally reflects the light output from the first port 13 a of the optical switch 13 and inputs the reflected light to the first port 13 a of the optical switch 13.

  The monitor unit 15 receives the light output from the second port 13b of the optical switch 13 and monitors the power of the received light. In order to prevent the light reflected by the light receiving surface of the monitor unit 15 from returning to the second port 13b of the optical switch 13, the light received by the monitor unit 15 with respect to the optical axis of the light reaching from the second port 13b of the optical switch 13 The surface is preferably not vertical, and the reflectance of the light receiving surface of the monitor unit 15 is preferably −40 dB or less. If the concentration length product of the optical amplifying fiber 11 is sufficiently large, the residual pumping light is small. However, if the concentration length product of the optical amplifying fiber 11 is small, the residual pumping light is transmitted from the end face 11b of the optical amplifying fiber 11. Therefore, it is preferable that an optical filter (not shown) for blocking excitation light is provided between the optical switch 13 and the monitor unit 15.

  The output light power adjuster 16 receives light output from the end face 11a of the optical amplifying fiber 11 and transmitted through the lens 18A and the dichroic mirror 19, and amplifies or attenuates this light to output it. That is, the output optical power adjuster 16 is an optical amplifier or an optical attenuator. The amplification factor or attenuation factor of the output optical power adjuster 16 is variable.

  The control unit 10 receives an optical monitoring result from the monitor unit 15, controls the output of pumping light from the pumping light source 12, controls the state setting of the optical switch 13 by the driving circuit 14, and outputs the optical power regulator 16. Controls the optical power adjustment by.

  In the laser apparatus 1 configured as described above, the excitation light continuously output from the excitation light source 12 is reflected by the dichroic mirror 19, collected by the lens 18 </ b> A, and the end face 11 a of the optical amplifying fiber 11 that is a laser medium. And the fluorescent element added to the optical amplifying fiber 11 is excited. That is, these components act as excitation means for continuously supplying excitation energy to the optical amplifying fiber 11 that is a laser medium.

  Further, when the first optical path between the first port 13 a and the third port 13 c of the optical switch 13 is in a light-passable state, the gap between the end surface 11 a of the optical amplifying fiber 11 and the total reflection mirror 17 is The optical system constitutes a Fabry-Perot type laser resonator, and an optical amplifying fiber 11 as a laser medium is disposed on the resonance optical path of the laser resonator. In addition, when the second optical path between the second port 13b and the third port 13c of the optical switch 13 is in a light-passable state, the resonance loss of the laser resonator is maximized, and optical amplification as a laser medium is performed. The light output from the optical fiber 11 is monitored by the monitor unit 15. Thus, the optical switch 13 and the drive circuit 14 can act as Q switch means for modulating the resonator loss of the laser resonator, and can output pulsed laser light from the laser resonator.

  The control unit 10 then sets the resonator loss of the laser resonator to the first predetermined loss for high-power pulse non-oscillation (when the second optical path is in a light-passable state). ) With the resonator loss of the laser resonator set to the second predetermined loss for high-power pulse oscillation based on the optical power monitored by the monitor unit 15 (the first optical path can pass light) Control is performed to stabilize the peak power or energy of the output laser light pulse. More preferably, the control unit 10 outputs an output when the resonator loss of the laser resonator is minimum based on the optical power monitored by the monitor unit 15 immediately before the resonator loss of the laser resonator becomes minimum. Stabilizes and controls the peak power or energy of the emitted laser light.

  More specifically, the control unit 10 stabilizes the peak power or energy of the output laser light by controlling the magnitude of the excitation energy supplied from the excitation light source 12 to the optical amplifying fiber 11. Alternatively, the control unit 10 stabilizes the peak power or energy of the output laser light by controlling the gain or loss of the output light power adjuster 16.

  A specific configuration example of the laser light source 1 according to the first embodiment is as follows. The optical amplifying fiber 11 is an optical fiber in which a Yb element is added to the optical waveguide region, and the excitation light source 12 outputs excitation light having a wavelength of 915 nm band that can excite the Yb element. At this time, the optical amplifying fiber 11 is It emits fluorescence with a wavelength of 1.06 μm. The optical amplifying fiber 11 has a length of 10 m, a core diameter of 10 μm, an inner cladding diameter of 125 μ, and a wavelength 915 nm band unsaturated absorption of 10.76 dB / m. The power of the wavelength 915 nm band excitation supplied from the excitation light source 12 to the optical amplifying fiber 11 is 6.3 W. The optical switch 13 uses an acousto-optic effect (AO switch), and the drive circuit 14 applies an RF voltage to the AO switch 13. The switching repetition frequency of the AO switch 13 is 10 kHz, and the required switching time of the AO switch 13 is 500 ns.

  FIG. 2 is a diagram illustrating an output pulse waveform of the laser light source 1 when the stabilization control by the control unit 10 is not performed. FIG. 3 is an enlarged view showing an output light waveform in a time zone other than the time of pulse output of the laser light source 1 when the stabilization control by the control unit 10 is not performed. FIG. 4 is a chart showing the peak power of each output pulse of the laser light source 1 and the energy per pulse when the stabilization control by the control unit 10 is not performed. When the stabilization control by the control unit 10 is not performed, a part of the light output from the end face 11 b of the optical amplifying fiber 11 is reflected by the third port 13 c of the AO switch 13 and the reflected light is reflected by the optical amplifying fiber 11. Since the return light ratio is about -23 dBc, the output light waveform of the laser light source 1 is a relaxation oscillation type. Further, it can be seen from FIG. 4 that the odd-numbered pulses are generally strong and the even-numbered pulses are weak.

  FIG. 5 is a diagram showing the relationship between the optical power value monitored by the monitor unit 15 immediately before the resonator loss of the laser resonator of the laser light source 1 is minimized and the energy value of the output pulsed light. FIG. 6 is a diagram illustrating the relationship between the optical power value monitored by the monitor unit 15 immediately before the resonator loss of the laser resonator of the laser light source 1 is minimized and the peak power value of the output pulsed light. FIG. 7 is a diagram illustrating the relationship between the optical power average value monitored by the monitor unit 15 and the energy value of the output pulse light during a period in which the resonator loss of the laser resonator of the laser light source 1 is not minimal. FIG. 8 is a diagram showing the relationship between the optical power average value monitored by the monitor unit 15 and the peak power value of the output pulse light during the period when the resonator loss of the laser resonator of the laser light source 1 is not minimal.

  The term “immediately before the resonator loss of the laser resonator is minimized” means that the first optical path between the first port 13a and the third port 13c of the AO switch 13 is in a state where light can pass through and a pulse is emitted from the laser resonator. This is just before the laser beam is output. The period in which the resonator loss of the laser resonator is not minimal is a period in which the first optical path is not in a light-passable state.

  As can be seen from these drawings, the optical power value monitored by the monitor unit 15 and the energy value of the output pulse light during the period when the resonator loss of the laser resonator of the laser light source 1 is not minimum (particularly immediately before it becomes minimum). Or, there is a good correlation with the peak power value. Therefore, in the case of thermal processing in which the pulse energy is required to be stable, etc., the control unit 10 monitors the resonator loss of the laser resonator of the laser light source 1 during a period that is not minimal (particularly immediately before it is minimized). Based on the optical power value monitored by the unit 15, the output of the pumping light from the pumping light source 12 or the optical power adjustment by the output optical power adjuster 16 is feedforward controlled to stabilize the pulse energy of the output pulsed light. be able to.

  Since the control by the control unit 10 in the laser light source 1 according to the present embodiment is feedforward control, the output power value of the pumping light from the pumping light source 12 or the optical power adjustment amount by the output light power adjuster 16 and the output pulse light The correlation with the pulse energy is measured in advance and stored in the control unit 10. This correlation is preferably approximated by a linear function. In this case, the load on the processing unit in the control unit 10 is small. The processing unit in the control unit 10 is configured by, for example, an FPGA (Field Programmable Gate Array). In addition, the processing unit in the control unit 10 may perform an operation according to a linear function expression representing the correlation, or may refer to a table storing the correlation, but is capable of high-speed processing. The latter is preferred.

  If feedback control as disclosed in Patent Document 1 is performed, for example, the pulse # 4 shown in FIG. 4 is monitored, and it is detected that the peak power of the pulse # 4 is small. If feedback is made to increase the pumping light power to improve the output based on this, the peak power of the next pulse # 5 will be further increased depending on the control delay time, and the stability of the pulse peak value will be increased. May result in damage. On the other hand, in this embodiment, since feedforward control is performed about each pulse, the peak power or energy of each pulse can be stabilized.

  Further, in this embodiment, since it is not necessary to insert a branch coupler for monitoring the output laser beam, the number of parts and connection points are reduced, the risk of optical damage is avoided, and insertion loss is reduced. The rise is suppressed.

  (Second Embodiment)

  Next, a second embodiment of the laser light source according to the present invention will be described. FIG. 9 is a configuration diagram of the laser light source 2 according to the second embodiment. The laser light source 2 shown in this figure includes a control unit 20, an optical amplifying fiber 21, an excitation light source 22, an optical switch 23, a drive circuit 24, a monitor unit 25, an output light power adjuster 26, an optical coupler 27A, and an optical coupler 27B. And an optical isolator 28.

  The optical amplifying fiber 21 is an optical fiber in which a fluorescent element is added to an optical waveguide region, and emits fluorescence from the fluorescent element when excitation light having a wavelength capable of exciting the fluorescent element is supplied. . This fluorescent element is preferably a rare earth element, and among them, Er element, Yb element and the like are preferable. One end of the optical amplifying fiber 21 is connected to the optical coupler 27A, and the other end of the optical amplifying fiber 21 is connected to the optical coupler 27B.

  The excitation light source 22 continuously outputs excitation light for exciting the fluorescent element added to the light amplifying fiber 21. The excitation light source 22 preferably includes a laser diode. The optical coupler 27 </ b> A receives the excitation light output from the excitation light source 22 and outputs the excitation light to the optical amplifying fiber 21. In addition, the optical coupler 27 </ b> A receives light that has arrived from the optical isolator 28, and outputs this light to the optical amplifying fiber 21.

  The optical switch 23 has a first port 23a, a second port 23b, a third port 23c, and a fourth port 24d. The first port 23a is optically connected to the optical isolator 28, the second port 23b is optically connected to the monitor unit 25, the third port 23c is optically connected to the optical coupler 27B, and the fourth port. Reference numeral 23d denotes a non-reflective terminal. The optical switch 23 is driven and operated by the drive circuit 24, and is one of the first optical path between the first port 23a and the third port 23c and the second optical path between the second port 23b and the third port 23c. However, the light can be selectively transmitted. The optical switch 23 preferably uses a piezo optical effect, and may use an acousto-optic effect.

  The monitor unit 25 receives the light output from the second port 23b of the optical switch 23 and monitors the power of the received light. If the concentration length product of the optical amplifying fiber 21 is sufficiently large, the residual pumping light is small. If the concentration length product of the optical amplifying fiber 21 is small, the residual pumping light is transmitted from the second port 23b of the optical switch 23. Therefore, it is preferable that an optical filter (not shown) for blocking the excitation light is provided between the optical switch 23 and the monitor unit 25.

  The optical coupler 27 </ b> B receives light that has arrived from the optical amplifying fiber 21, branches a part of the light, outputs it to the output optical power adjuster 26, and outputs the remaining part to the second port 23 c of the optical switch 23. . The output light power adjuster 26 receives light that has been output from the end of the optical amplifying fiber 21 and arrived through the optical coupler 27B, and amplifies or attenuates this light to output it. That is, the output optical power adjuster 26 is an optical amplifier or an optical attenuator. The amplification factor or attenuation factor of the output optical power adjuster 26 is variable.

  The optical isolator 28 allows light that has arrived from the first port 23a of the optical switch 23 to pass toward the optical coupler 27A, but does not allow light to pass in the opposite direction.

  The control unit 20 receives an optical monitor result from the monitor unit 25, controls the output of pumping light from the pumping light source 22, controls the state setting of the optical switch 23 by the drive circuit 24, and outputs light power adjuster 26. Controls the optical power adjustment by.

  In the laser apparatus 2 configured as described above, the pumping light continuously output from the pumping light source 22 is supplied to the optical amplifying fiber 21 that is a laser medium via the optical coupler 27A, and is added to the optical amplifying fiber 21. Excited fluorescent elements. That is, these components act as excitation means for continuously supplying excitation energy to the optical amplifying fiber 21 that is a laser medium.

  Further, when the first optical path between the first port 23a and the third port 23c of the optical switch 23 is in a light-passable state, the optical amplifying fiber 21, the optical coupler 27B, the optical switch 23, and the optical isolator 28. The optical system including the optical coupler 27A constitutes a ring type laser resonator, and an optical amplifying fiber 21 as a laser medium is disposed on the resonance optical path of the laser resonator. In addition, when the second optical path between the second port 23b and the third port 23c of the optical switch 23 is in a light-passable state, the resonance loss of the laser resonator is maximized, and optical amplification as a laser medium is performed. The light output from the optical fiber 21 is monitored by the monitor unit 25. As described above, the optical switch 23 and the drive circuit 24 can act as Q switch means for modulating the resonator loss of the laser resonator, and can output pulsed laser light from the laser resonator.

  The control unit 20 then sets the resonator loss of the laser resonator to the first predetermined loss for high-power pulse non-oscillation (when the second optical path is in a light-passable state). ) In a state where the resonator loss of the laser resonator is set to the second predetermined loss for high-power pulse oscillation based on the optical power monitored by the monitor unit 25 (the first optical path can pass light) Control is performed to stabilize the peak power or energy of the output laser light pulse. More preferably, the control unit 20 outputs when the resonator loss of the laser resonator is minimum based on the optical power monitored by the monitor unit 25 immediately before the resonator loss of the laser resonator becomes minimum. Stabilizes and controls the peak power or energy of the emitted laser light.

  More specifically, the control unit 20 stabilizes the peak power or energy of the output laser light by controlling the magnitude of the excitation energy supplied from the excitation light source 22 to the optical amplifying fiber 21. Alternatively, the control unit 20 controls the gain or loss of the output light power adjuster 26 to stabilize the peak power or energy of the output laser light.

  Since the control by the control unit 20 in the laser light source 2 according to this embodiment is also feedforward control, the output power value of the pumping light from the pumping light source 22 or the optical power adjustment amount by the output light power adjuster 26 and the output pulse light The correlation with the pulse energy is measured in advance and stored in the control unit 20. This correlation is preferably approximated by a linear function. In this case, the load on the processing unit in the control unit 20 is small. The processing unit in the control unit 20 may perform an operation according to a linear function expression representing the correlation, or may refer to a table storing the correlation, but is capable of high-speed processing. The latter is preferred. Thus, also in this embodiment, since feedforward control is performed for each pulse, the peak power or energy of each pulse can be stabilized.

  Also in this embodiment, since it is not necessary to insert a branch coupler for monitoring the output laser beam, the number of parts and connection points are reduced, the risk of optical damage is avoided, and insertion loss is reduced. The rise is suppressed.

DESCRIPTION OF SYMBOLS 1, 2 ... Laser light source, 10 ... Control part, 11 ... Optical amplifying fiber, 12 ... Excitation light source, 13 ... Optical switch, 14 ... Drive circuit, 15 ... Monitor part, 16 ... Output light power regulator, 17 ... All Reflection mirror, 18A, 18B ... lens, 19 ... dichroic mirror, 20 ... control unit, 21 ... optical amplifying fiber, 22 ... excitation light source, 23 ... optical switch, 24 ... drive circuit, 25 ... monitor unit, 26 ... output light Power regulator, 27A, 27B ... optical coupler, 28 ... optical isolator.

Claims (7)

A laser light source that oscillates a laser beam,
A laser resonator in which a laser medium that generates emission light by being supplied with excitation energy is disposed on a resonance optical path;
Excitation means for continuously supplying excitation energy to the laser medium;
According to the excitation energy supply by the excitation means, a monitor unit for monitoring the power of the light extracted from the middle of the optical path in the resonator,
Q switch means for modulating a resonator loss of the laser resonator and switching an optical path output to the monitor unit according to the resonator loss;
An output optical power adjuster for amplifying or attenuating the laser light output from the laser resonator;
Based on the emitted light power monitored by the monitor unit in a state where the resonator loss of the laser resonator is set to a first predetermined loss for high-power pulse non-oscillation, the resonator of the laser resonator When the loss is set to the second predetermined loss for high-power pulse oscillation, the physical parameters in the resonator are controlled so as to stabilize the energy of the laser light pulse to be output, and the output laser light A laser light source comprising: a control unit that controls the gain or loss of the output light power adjuster so as to stabilize the peak power of the pulse.   The control unit performs feedback control of a physical parameter in the resonator that affects the output characteristics of the laser light source based on the emitted light power monitored by the monitor unit, thereby controlling the peak power or energy of the output laser light. The laser light source according to claim 1, wherein the laser light source is stabilized.   The laser resonator includes the Q switch means, and in the Q switch means, a pair of ports constitutes a part of the laser resonator, and one of the remaining ports is the optical power in the laser resonator. The laser light source according to claim 1, wherein the laser light source is used for monitoring a part of the laser light source.   4. The laser light source according to claim 3, wherein the optical switch uses an acoustooptic effect.   4. The laser light source according to claim 3, wherein the optical switch uses an electro-optic effect.   4. The laser light source according to claim 3, wherein the optical switch uses a piezo optical effect. The control unit performs control based on the emitted light power monitored by the monitor unit at the end of the period in which the resonator loss is set to the first predetermined loss. The laser light source according to claim 1, wherein power or energy is stabilized.

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