KR102212968B1 - Apparatus and Method for monitoring polarization status and controlling of high power fiber laser for spectral beam combining - Google Patents

Abstract

The present invention provides a device for monitoring a polarization state of a high-power fiber laser for wavelength-controlled beam coupling, which does not lower linear polarization even in the application of a non-polarization optical fiber. The device for monitoring the polarization state includes: a plurality of fiber laser modules each arranged in a plurality of channels; an optical system assembly for combining the laser beams from the plurality of fiber laser modules to a wavelength control beam; and a polarization control signal processor providing an output signal for polarization state monitoring to the plurality of fiber laser modules.

Description

Apparatus and Method for monitoring polarization status and controlling of high power fiber laser for spectral beam combining}

The present invention relates to a fiber laser technology, and more particularly, to an apparatus and method for monitoring a polarization state based on a single channel and a free optical base for a single channel and a single channel.

Continuous research and development has been made to increase the output of high-power lasers and/or improve the beam quality. Among them, fiber lasers are the form of solid-state lasers capable of outputting high-quality laser beams, and have recently emerged as the main force in the commercial and defense laser markets.

However, it is possible to output a single mode laser beam in a narrow area of several to several tens of μm in diameter of the fiber core, and to increase the output of such a high-quality laser beam, a high-power pump beam must be input. At this time, nonlinear phenomena such as Stimulated Brillouin Scattering (SBS), Mode Instability (MI), and Stimulated Raman Scattering (SRS) occur due to the high energy density concentration in the core. , This became a limiting factor in increasing the power of a single fiber laser module.

One way to overcome the most dominant induced Brillouin scattering among these phenomena is to configure an amplifier with non-polarized (Non-PM) optical fibers. The problem that occurs at this time is that the linear polarization is lowered by the application of the non-polarization optical fiber, and thus the efficiency and coupling properties are deteriorated when the phase control or wavelength control beam combining technology that combines beams based on the linearly polarized beam is applied.

1. Korean Patent Registration No. 10-1937404 (Registration Date: 2019.01.04) 2. Korean Patent Publication No. 10-2006-103868

The present invention has been proposed in order to solve the above problems related to the background technology, and provides an apparatus and method for monitoring the polarization state of a high-power fiber laser for wavelength-controlled beam coupling in which linear polarization does not decrease even when non-polarization optical fibers are applied. have.

In addition, the present invention provides an apparatus and method for monitoring the polarization state of a high-power optical fiber laser for wavelength-controlled beam coupling that can prevent deterioration in efficiency and coupling when applying a phase control or wavelength-controlled beam coupling technology that combines beams based on a linearly polarized beam. It has a different purpose to provide.

The present invention provides an apparatus for monitoring a polarization state of a high-power fiber laser for wavelength-controlled beam coupling in which linear polarization does not decrease even when a non-polarization optical fiber is applied in order to achieve the above-described problem.

The polarization state monitoring device,

A plurality of fiber laser modules each arranged in a plurality of channels;

An optical system assembly for coupling laser beams from the plurality of fiber laser modules to a wavelength controlled beam;

And a polarization control signal processor that provides an output signal for monitoring a polarization state to the plurality of fiber laser modules.

In addition, the polarization state monitoring apparatus includes; an optical sensor (balanced detector) for receiving the vertically polarized beam generated from the optical system assembly, generating an input signal according to the polarization state, and transmitting the input signal to the polarization control signal processor; To do.

In addition, the polarization state has a linear distribution according to each wavelength and is an array type value.

In addition, the optical system assembly may include a transmission optical system for transmitting the laser beams; A diffraction grating for combining the laser beams at a single diffraction angle to output a final laser beam; And an imaging optical system for polarization monitoring that monitors each laser beam whose output is reduced by transmitting the diffraction grating for beam combining.

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In addition, the optical system assembly may include a beam attenuator for reducing each laser beam whose output is reduced to a preset output to prevent damage to the optical sensor.

In addition, it characterized in that it comprises a; transmission type diffraction grating for generating a vertically polarized beam having a linear polarization of a predetermined reference or more of the laser light reduced to a preset output by the beam attenuator.

In addition, the transmission type diffraction grating may be installed so that the direction of the beam combining diffraction grating and the linear grating match.

In addition, the transmission type diffraction grating may be any one of a volume bragg grating (VBG) method, an embedded transmission grating (ETG) method, and a wire grid polarizer (WGP) type device.

On the other hand, another embodiment of the present invention, a plurality of fiber laser modules each arranged in a plurality of channels; A main optical system assembly for collimating and incident laser beams from the plurality of fiber laser modules in parallel; A sub optical system assembly that combines the collimated and incident laser beams into a wavelength controlled beam; And a polarization control signal processor that provides an output signal for monitoring a polarization state to the plurality of fiber laser modules. A device for monitoring a polarization state of a fiber laser for wavelength-controlled beam combining is provided.

In this case, the polarization state monitoring apparatus may include: a first optical sensor that receives a first vertically polarized beam generated from the main optical system assembly, generates a first input signal according to a polarization state, and transmits the first input signal to the polarization control signal processor; And a second optical sensor configured to receive a second vertically polarized beam generated from the sub optical system assembly, generate a second input signal according to a polarization state, and transmit the second input signal to the polarization control signal processor. It characterized in that it comprises a.

In addition, the main optical system assembly may include a transmission optical system for transmitting the laser beams; A first diffraction grating for diffracting the laser beams at a plurality of diffraction angles; And a first polarization monitoring imaging optical system for monitoring each laser beam whose output is reduced by transmitting the first diffraction grating for beam combining.

In addition, the sub-optical system assembly may include: a second diffraction grating for diffracting laser beams diffracted from the first diffraction grating for beam combining to output a final laser beam; And a second polarization monitoring imaging optical system for monitoring each laser beam whose output has been reduced by transmitting the second diffraction grating for beam combining.

(여기서, λi 및 λ는 i 및 j번째 채널의 파장을 나타내며, TE는 수직 편광을 나타내 회절격자1은 제 1 빕결함용 회절격자를 나타내고, 회절격자2는 제 2 빔결합용 회절격자를 나타낸다)에 의해 예측되는 것을 특징으로 한다.In addition, the polarization state is Equation

(Where λi and λ represent the wavelengths of the i and j-th channels, TE represents vertical polarization, diffraction grating 1 represents the first diffraction grating for bib defects, and diffraction grating 2 represents the second diffraction grating for beam coupling. ) Predicted by.

On the other hand, another embodiment of the present invention includes the steps of: (a) providing an output signal to a plurality of fiber laser modules each of which a polarization control signal processor is arranged in a plurality of channels; (b) wavelength-controlled beam coupling of laser beams from the plurality of optical fiber laser modules by an optical system assembly; And (c) generating the output signal by performing, by the polarization control signal processor, monitoring the polarization states of the plurality of fiber laser modules; monitoring the polarization state of the fiber laser for wavelength-controlled beam combining, comprising: Provides a way.

According to the present invention, it is possible to reduce the number of modules by increasing the output of a single laser module in which non-linearity is reduced by applying a non-PM optical fiber and increasing the output of a single module, thereby reducing the size and weight of a beam combining system.

In addition, as another effect of the present invention, it is possible to apply it to a directional energy weapon system using a high-power laser in the field of defense based on this, and to achieve an increase in laser power according to the system characteristics.

In addition, as another effect of the present invention, in the industrial field, it is possible to cut, weld, and bond thick materials in a short time by using a laser with high power and excellent beam quality, and nuclear fusion or other next-generation energy that requires high energy concentration. It can also be applied to technology.

In addition, as another effect of the present invention, it is possible to perform physical property analysis in a high energy state using a high-power laser in the academic field.

1 is a block diagram of a configuration of an apparatus 100 for monitoring a polarization state of a high-power fiber laser for wavelength-controlled beam coupling according to an embodiment of the present invention.
2 is a block diagram illustrating a configuration of a multi-channel polarization state monitoring apparatus in a wavelength controlled beam combining method using a single diffraction grating according to another embodiment of the present invention.
3 is a block diagram of a configuration of a multi-channel polarization state monitoring apparatus in a wavelength-controlled beam combining method using a double diffraction grating according to another embodiment of the present invention.
4 is a flowchart illustrating a process of monitoring a single channel polarization state according to an embodiment of the present invention.
5 is a flowchart illustrating a multi-channel polarization state monitoring process according to another embodiment of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all changes, equivalents, or substitutes included in the spirit and scope of the present invention.

In describing each drawing, similar reference numerals are used for similar elements. Terms such as first and second may be used to describe various elements, but the elements should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component.

For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. The term "and/or" includes a combination of a plurality of related stated items or any of a plurality of related stated items.

Unless otherwise defined, all terms including technical or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Shouldn't.

Hereinafter, an apparatus and method for monitoring a polarization state of a high-power fiber laser for wavelength-controlled beam coupling according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a configuration of an apparatus 100 for monitoring a polarization state of a high-power fiber laser for wavelength-controlled beam coupling according to an embodiment of the present invention. Referring to FIG. 1, the polarization condition monitoring apparatus 100 may include a fiber laser module 10, a balanced detector 116, a polarization control signal processor 117, a controller 120, and the like. I can.

The optical fiber laser module 10 includes a seed LD 101, a line width modulator 102, a polarization modulator 104, an advertisement collector 105, an optical fiber amplifier 106, 107, 109, a coupler 103, 108, 111, and a CLS 110. do.

The line width of the laser light starting from the seed LD (Laser Diode) 101 is varied through the line width modulator 102 to suppress the induced Brillouin scattering. The seed LD (Laser Diode) 101 has a high power and outputs a narrowband laser.

The first coupler 103 is composed of a polarization maintening (PM) optical fiber and is used to provide a reference signal having a high linear polarization. The polarization modulator 104 is composed of a polarizing (PM) optical fiber to the input end. However, from the output after that, in order to transmit the laser light whose polarization state is changed through the polarization modulator 104 as it is, it is composed of a non-polarization (Non-PM) optical fiber.

The polarization modulator 104 is an element that receives an electric/electronic control signal from the polarization control signal processor 117 and changes the polarization state of the laser light guided in the optical fiber. Depending on the modulation type, (1) a type of fiber squeezer that applies mechanical stress to the optical fiber with a piezoelectric material (PZT) piezoelectric element, and (2) a LiNiO ₃ crystal type whose birefringence is changed by the electric potential difference applied, (3) A type using a liquid crystal whose molecular arrangement changes due to a potential difference and (4) a method of changing a birefringence using a Faraday electromagnet can be applied.

The advertisement granulator 105 is applied to protect the previous stage device with Rayleigh and induced Brillouin scattered light reflected back from the first to third optical fiber amplifiers 106, 107, and 109. The second coupler 108 is used to receive the laser light reflected back from the third optical fiber amplifier 109. The retroreflected laser light contains information about the final output stage laser light that is arbitrarily polarized to be controlled by polarization modulation. The first to third optical fiber amplifiers (106, 107, 109) are optical fiber gain media such as Yb, Er, Yb/Er co-doping, Tm and Ho (output wavelength dependent), advertisement It may be composed of a granulator, a pump LD (output wavelength dependent), and a pump optical coupler.

A cladding light stripper (CLS) 110 is used to remove residual pump LD light and clad mode light. The third coupler 111 is used to divide a part of the high-power laser light to obtain a positively-polarized high-power laser optical signal. The transmission optical fiber 112 is configured by applying an end-cap, a high-transmission dielectric coating, and a clad mode light removal structure in order to safely output high-power laser light without loss.

The polarized forward optical signal 113 from the seed LD 101, the reverse optical signal 114 from the optical fiber amplifier 109, and the randomly polarized high power laser optical signal 115 in the forward direction are optical sensors for comparison output. It is input to the (balanced detector) 116 and input to the polarization control signal processor 117 as an electric and electronic signal.

In this case, a polarization state, a convolution, and a correlation are performed according to the above equation to obtain a calculation and control signal. In addition, to maximize vertical linear polarization, Stochastic Parallel Gradient Decent (SPGD), Stochastic Parallel Gradient Ascending (SPGA), Global optimization algorithm, Genetic finding algorithm, Hill Climbing algorithm , By applying a machine learning technique, etc., by driving the polarization modulator 104 with the control output signal predicted and calculated through the above algorithm to obtain and control the linear polarization.

The controller 120 performs a function of exchanging signals with and controlling components. To this end, the controller 120 may be composed of a microprocessor, a memory, a circuit, a program, and the like.

Memory is a flash memory type, hard disk type, multimedia card micro type, card type memory (for example, SD (Secure Digital) or XD (eXtreme Digital)) Memory, etc.), RAM (Random Access Memory, RAM), SRAM (Static Random Access Memory), ROM (Read Only Memory, ROM), EEPROM (Electrically Erasable Programmable Read Only Memory), PROM (Programmable Read Only Memory), magnetic memory , A magnetic disk and an optical disk, and may include at least one type of storage medium. In addition, it may operate in connection with a web storage or a cloud server that performs a storage function on the Internet.

Of course, in FIG. 1, the controller 120 is separately configured, but it is also possible to incorporate it into the polarization control signal processor 117.

2 is a block diagram illustrating a configuration of a multi-channel polarization state monitoring apparatus in a wavelength controlled beam combining method using a single diffraction grating according to another embodiment of the present invention. Referring to FIG. 2, the multi-channel polarization state monitoring apparatus includes first to nth fiber laser modules 10-1 to 10-n, an optical system assembly 200, an optical sensor 216, and the like. I can.

The first to nth optical fiber laser modules 10-1 to 10-n are, the seed LD 101, the line width modulator 102, the polarization modulator 104, the advertising agent 105, the first to third optical fiber amplifiers. (106, 107, 109), the first to third couplers 103, 108, 111 and the CLS 110 may all be included.

The optical system assembly 200 includes a transmission optical fiber 202, a transmission optical system 204, a diffraction grating 205 for beam combining, an imaging optical system 206 for polarization monitoring, a beam attenuator 207, a transmission type grating 208, etc. It can be configured to include. The transmission optical system 204 may include a condensing lens that condenses laser light.

These modules may be arranged up to 1 to n channels, and the arranged transmission optical fibers 202 may be mechanically coupled and fused at regular intervals in the optical fiber array structure 203 to be integrated.

The high-power laser light arranged in 1 to n channels is transmitted to the diffraction grating 205 for beam combining at an incident angle capable of beam combining through the transmission optical system 204. Therefore, the output is increased by combining at one diffraction angle through the diffraction grating 205 for beam combining. At this time, the laser light of each channel whose output has been reduced by passing through the beam coupling diffraction grating 205 is spatially focused through the polarization monitoring imaging optical system 206, and the optical sensor 116 through the beam attenuator 207 ) To prevent damage and reduce to output.

The transmission type diffraction grating 208 is installed so that the direction of the linear grating coincides with the diffraction grating 205 for beam combining, and the VBG (Volume Bragg grating), ETG (embedded transmission grating), WGP (wire grid polarizer) type elements, etc. can do. The transmission diffraction grating 208 may be replaced with a Transverse Electric Field (TE) polarizer.

The TE polarized beam 209 having a high linearly polarized light passing through the transmission type diffraction grating 208 is received by the optical sensor 216 according to the wavelength of each channel narrow-band fiber laser. The optical sensor 216 may be a linear optical sensor.

At this time, the polarization state received by the photosensor 216 has a linear distribution according to each wavelength, which is provided as an input signal of the polarization control signal processor 117 in an (n × 1) array type value. Here, n is the number of channels connected to the optical fiber array. It indicates that the electronic signal input through the optical sensor is a vector type.

In this case, the polarization state for each channel can be predicted according to the following equation.

λi represents the wavelength of the i-th channel.

This is determined by a light-receiving position formed by the optical sensor 216 by an angle incident on the diffraction grating 205 for beam combining. Stochastic Parallel Gradient Decent (SPGD), Stochastic Parallel Gradient Ascending (SPGA), Global optimization algorithm, Genetic finding algorithm, Hill climbing algorithm to maximize vertical linear polarization for each channel through the above formula (Hill Climbing algorithm), machine learning techniques, etc. can be applied.

The polarization modulator 104 in the first to nth fiber laser modules 10-1 to 10-n is driven with the control output signal predicted and calculated through the above algorithm to obtain and control the linear polarization. On the other hand, the optical sensor 116 shown in FIG. 1 receives a polarized signal through an optical fiber, whereas the optical sensor 216 shown in FIG. 2 has a function of receiving a polarized signal for each channel in the combined laser beam. Perform.

3 is a block diagram of a configuration of a multi-channel polarization state monitoring apparatus in a wavelength-controlled beam combining method using a double diffraction grating according to another embodiment of the present invention. 3, a multi-channel polarization state monitoring apparatus includes first to nth fiber laser modules 10-1 to 10-n, a main optical system assembly 300, a sub optical system assembly 310, and a first and It may be configured to include a second optical sensor (316-1, 316-2).

The first to nth optical fiber laser modules 10-1 to 10-n are, the seed LD 101, the line width modulator 102, the polarization modulator 104, the advertising agent 105, the first to third optical fiber amplifiers. (106, 107, 109), the first to third couplers 103, 108, 111 and the CLS 110 may all be included.

The main optical system assembly 300 includes a transmission optical fiber 202, a transmission optical system 204, a first diffraction pattern for beam combining 305, an imaging optical system 206 for polarization monitoring, a beam attenuator 207, and a transmission type diffraction grating ( 208) and the like. In addition, the sub optical system assembly 310 may include a second beam combining diffraction grating 311, a second imaging optical system 312 for monitoring, and the like. The transmission optical system 204 may include a collimating lens that emits laser light in the form of parallel light.

These modules can be arranged up to 1 to n channels, and the arranged transmission optical fibers 202 can be mechanically coupled and fused at regular intervals in the optical fiber arrangement structure 203 to be integrated. The high-power laser light arranged in 1 to n channels is collimated and incident in parallel to the first beam coupling diffraction grating 305 through the transmission optical system 204.

The diffraction angle of the first beam-combining diffraction grating 305 according to each channel wavelength is incident on the second beam-combining diffraction grating 311, and is finally output as a combined high-power beam. At this time, the laser light of each channel whose output is reduced by passing through the first beam combining diffraction grating 305 is spatially focused through the first polarization monitoring imaging optical system 206, and the light through the beam attenuator 207 The output is reduced to less than preventing damage to the sensor 316-1.

The transmission type diffraction grating 208 is installed so that the direction of the linear grating matches the first diffraction grating 305 for beam combining, and the VBG (Volume bragg grating), ETG (embedded transmission grating), WGP (wire grid polarizer) type device, etc. Can be applied. The first TE polarized beam 309 having a high linearly polarized light passing through the transmission type diffraction grating 208 is received by the first optical sensor 316-1 according to the wavelength of each channel narrowband fiber laser.

In this case, the polarization state received by the first photosensor 316-1 has a linear distribution according to each wavelength, which is provided as an input signal of the polarization control signal processor 117 in an (nx1) array type value. In this case, the polarization state for each channel may be predicted according to Equation 2. Therefore, to maximize the vertical linear polarization for each channel, Stochastic Parallel Gradient Decent (SPGD), Stochastic Parallel Gradient Ascending (SPGA), Global optimization algorithm, Genetic finding algorithm, Hill climbing algorithm Climbing algorithm) and machine learning techniques are applied to obtain and control the linear polarization by driving the polarization modulator 103 in the narrow-band fiber laser module 301 with the control output signal predicted and calculated through the above algorithm.

Additionally, laser light for each channel that has passed through the second diffraction grating 311 for beam combining is received by the second optical sensor 316-2 using the second imaging optical system 312 for monitoring. At this time, since the second TE polarized beam 313 is linearly polarized and diffracted through the first diffraction grating 305 for beam combining, a separate polarizer or a transmission type diffraction grating is not required.

Also in this case, the polarization state of each channel may be predicted according to Equation 2. Therefore, to maximize the vertical linear polarization for each channel, Stochastic Parallel Gradient Decent (SPGD), Stochastic Parallel Gradient Ascending (SPGA), Global optimization algorithm, Genetic finding algorithm, Hill climbing algorithm Climbing algorithm), machine learning technique, etc., and linearly polarized light by driving the polarization modulator 103 in the first to nth fiber laser modules 10-1 to 10-n with the control output signal predicted and calculated through the above algorithm. To acquire and control degrees. In addition, by mixing the above two structures, the polarization state can be accurately predicted as shown in the following equation.

Here, λi and λj represent the wavelengths of the i and j-th channels, which are incident and diffracted by the i-th first diffraction grating 305 and the j-th diffraction grating 311 for beam combining. It is determined by the light-receiving position formed by the first optical sensor 316-1 and the second optical sensor 316-2.

Stochastic Parallel Gradient Decent (SPGD), Stochastic Parallel Gradient Ascending (SPGA), Global optimization algorithm to maximize vertical linear polarization for each channel by convolution and correlation of signals according to the position of each grating through the above equation. , Genetic finding algorithm, Hill Climbing algorithm, machine learning method, etc., and the polarization modulator 104 in the first to nth fiber laser modules 10-1 to 10-n with the control output signal predicted and calculated through the above algorithm. ) To obtain and control the linear polarization.

4 is a flowchart illustrating a process of monitoring a single channel polarization state according to an embodiment of the present invention. Referring to Fig. 4, when the system is started and the self-diagnosis of the controller 120 is completed (steps S401 and S402), the system initializes and enters the oscillation mode (step S403). The analysis signal is obtained and the polarization modulated signal is output (steps S404 and S405), and the control is performed in a closed loop until the required linear polarization is reached (step S406), and the high-power normal oscillation is entered when the required linear polarization is reached. (Step S407) This control sequence can be applied to the single channel polarization state monitoring of FIGS. 1 and 4.

5 is a flowchart illustrating a multi-channel polarization state monitoring process according to another embodiment of the present invention. Referring to Fig. 5, when the system is started and the self-diagnosis of the controller 120 is completed (steps S501 and S502), the system is initialized and the oscillation mode is entered (step S503). In the state of applying power to the amplifier for each channel from 1 to n, and obtaining a polarization analysis signal for each channel from 1 to n, and outputting a polarization modulated signal (steps S504, S505), closed loop until the required linear polarization is reached. Control is performed by (closed loop) (step S506).

At this time, if there is a channel below the required linear polarization, it is determined whether it is controllable, and if it is determined as a faulty channel (steps S508 and S509), only the controllable channel is controlled in a closed loop so as to reach the required linear polarization (step S510). The algorithm loop is operated in two cases: normal oscillation with the controllable channel output or all channels high-power normal oscillation (steps S511 and S507). This control sequence can be applied to the multi-channel polarization state monitoring of FIG. 3.

In addition, the steps of the method or algorithm described in connection with the embodiments disclosed herein are implemented in the form of program instructions that can be executed through various computer means such as a microprocessor, a processor, a CPU (Central Processing Unit), etc. It can be recorded on any media. The computer-readable medium may include a program (command) code, a data file, a data structure, or the like alone or in combination.

The program (command) code recorded on the medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROM, DVD, Blu-ray, and the like, and ROM, RAM ( A semiconductor memory device specially configured to store and execute program (instruction) codes such as RAM), flash memory, and the like may be included.

Here, examples of the program (instruction) code include not only machine language codes such as those created by a compiler but also high-level language codes that can be executed by a computer using an interpreter or the like. The above-described hardware device may be configured to operate as one or more software modules to perform the operation of the present invention, and vice versa.

101: seed LD, 102: line width modulator, 103: first optical fiber coupler, 104: polarization modulator
105: advertisement granulator, 106: first optical fiber amplifier, 107: second optical fiber amplifier
108: second optical fiber coupler, 109: third optical fiber amplifier, 110: CLS
111: third optical fiber coupler, 112: transmission optical fiber, 116: optical signal sensor, 117: polarization control signal processor

Claims (16)

A plurality of fiber laser modules 10-1 to 10-n, each arranged in a plurality of channels;
An optical system assembly 200 for coupling a plurality of laser beams from the plurality of fiber laser modules 10-1 to 10-n with a wavelength control beam;
Including; a polarization control signal processor 117 for providing an output signal for polarization state monitoring to the plurality of the fiber laser modules (10-1 to 10-n),
Including; an optical sensor 216 that receives the vertically polarized beam 209 generated from the optical system assembly 200, generates an input signal according to a polarization state, and transmits it to the polarization control signal processor 117,
The polarization state has a linear distribution according to each wavelength and is an array type numerical value.
delete delete delete delete The method of claim 1,
The optical system assembly 200,
A transmission optical system 204 for transmitting a plurality of the laser beams;
A beam combining diffraction grating (205) for outputting a final laser beam by combining a plurality of the laser beams at one diffraction angle; And
Polarization monitoring imaging optical system 206 for monitoring each laser beam whose output is reduced by transmitting through the beam combining diffraction grating 205; monitoring the polarization state of a fiber laser for wavelength-controlled beam combining, comprising: Device.
The method of claim 6,
A beam attenuator 207 for reducing each laser beam whose output is degraded to a preset output to prevent damage to the optical sensor 216; of a fiber laser for wavelength-controlled beam combining, comprising: Polarization condition monitoring device.
The method of claim 7,
And a transmission-type diffraction grating 208 for generating a vertically polarized beam 209 having a linear polarization of a predetermined reference or more of the laser light reduced to an output preset by the beam attenuator 207. Optical fiber laser polarization condition monitoring device for wavelength-controlled beam coupling. The method of claim 8,
The transmission type diffraction grating (208) is a polarization state monitoring device of the optical fiber laser, characterized in that installed so as to match the direction of the linear grating with the diffraction grating (205) for beam combining.
The method of claim 8,
The transmission type diffraction grating 208 is a device for monitoring a polarization state of an optical fiber laser, characterized in that it is any one of a volume bragg grating (VBG) method, an embedded transmission grating (ETG) method, and a wire grid polarizer (WGP) method.
A plurality of fiber laser modules 10-1 to 10-n, each arranged in a plurality of channels;
A main optical system assembly 300 for collimating and entering a plurality of laser beams from the plurality of fiber laser modules 10-1 to 10-n in parallel;
A sub-optical system assembly 310 for combining a plurality of collimated and incident laser beams with a wavelength-controlled beam; And
A polarization control signal processor 117 providing an output signal for monitoring a polarization state to the plurality of fiber laser modules 10-1 to 10-n;
Polarization state monitoring device of a fiber laser for wavelength control beam coupling comprising a.
The method of claim 11,
A first optical sensor (316-) for receiving the first vertical polarization beam 309 generated from the main optical system assembly 300, generating a first input signal according to a polarization state, and transmitting the first input signal to the polarization control signal processor 117 One); And
A second optical sensor 316-receiving the second vertical polarization beam 313 generated from the sub optical system assembly 310, generating a second input signal according to a polarization state, and transmitting the second input signal to the polarization control signal processor 117 2); Polarization state monitoring device of a fiber laser for wavelength-controlled beam coupling comprising a.
The method of claim 12,
The main optical system assembly 300,
A transmission optical system 204 for transmitting a plurality of the laser beams;
A first diffraction grating (305) for diffraction output of the plurality of laser light by diffraction of the plurality of laser light at a plurality of diffraction angles; And
Optical fiber laser for wavelength-controlled beam coupling, comprising: a first polarization monitoring imaging optical system 206 for monitoring each laser beam whose output has been reduced by transmitting through the first diffraction grating 205 for beam coupling. Polarization state monitoring device.
The method of claim 13,
The sub optical system assembly 310,
A second diffraction grating 311 for diffracting the plurality of laser beams diffracted from the first diffraction grating 305 for outputting a final laser beam; And
An optical fiber laser for wavelength-controlled beam coupling, comprising: a second polarization monitoring imaging optical system 312 for monitoring each laser beam whose output has been reduced by transmitting through the second diffraction grating 311 for beam coupling. Polarization state monitoring device.
The method of claim 14,
The polarization state is Equation

(Where λi and λ represent the wavelengths of the i and j-th channels, TE represents vertical polarization, diffraction grating 1 represents the first diffraction grating 305 for bib defects, and diffraction grating 2 represents the second diffraction for beam coupling A device for monitoring the polarization state of a fiber laser for wavelength-controlled beam coupling, characterized in that predicted by a grating 311).
(a) providing an output signal to a plurality of fiber laser modules 10-1 to 10-n, each of which the polarization control signal processor 117 is arranged in a plurality of channels;
(b) wavelength-controlled beam coupling of laser beams from the plurality of optical fiber laser modules 10-1 to 10-n by the optical system assembly 200; And
(c) generating the output signal by the polarization control signal processor 117 monitoring polarization states of the plurality of optical fiber laser modules 10-1 to 10-n; and
(d) receiving, by the optical sensor 216, the vertically polarized beam 209 generated from the optical system assembly 200, generating an input signal according to the polarization state, and transmitting it to the polarization control signal processor 117; Including,
The polarization state has a linear distribution according to each wavelength and is an array type numerical value.

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