KR20220116830A - Fiber directioning device and laser beam combining apparatus for the same - Google Patents

Abstract

According to the present invention, an optical fiber directing device includes: a piezoelectric element which performs z-axis movement along in a z-axis direction; a push structure connected to the piezoelectric element and displaced along a z axis; an ejection body through which an optical fiber passes; a direction converter which is provided on the outside of the ejection body and comes contact with the push structure to change z-axis displacement into a displacement in a direction inclined to the z-axis, so that the ejection body is displaced in the xy direction; a lens provided in front of the ejection body; and a restoration body which maintains the position and posture of the ejection body. Therefore, it is possible to increase the efficiency of beam combining by implementing a low conformal fill factor.

Description

Fiber directing device and laser beam combining apparatus using an optical fiber directing device TECHNICAL FIELD

The present invention relates to an optical fiber directing device and a laser beam combining device using the optical fiber directing device.

The optical fiber directing device refers to a device that changes the propagation direction of light emitted by electrically high-speed active control of the tip of an optical fiber. The optical fiber directing device may perform a function of scanning the traveling direction of light emitted from a single optical fiber at high speed. The optical fiber directing device may be referred to as an adaptive fiber directing device.

At least two or more of the optical fiber directing devices may be synchronized. A typical use of the optical fiber directing device is a laser beam combining device for focusing a laser beam from a plurality of optical fiber bundles to a single point.

Examples of the laser beam combining device are: First, a high-energy laser device for national defense that increases optical density by actively controlling the output end of a continuous oscillation multi-channel fiber laser and focusing it on one point; Second, a pulsed multi-channel optical fiber There is a space satellite garbage disposal device that increases the optical density by actively controlling the output end of the laser and focusing it on one point. . In addition, since the laser beam coupling device can increase the output by combining the laser beam, it can be a good way to overcome the advantages of the low power optical fiber laser device.

In the optical fiber directing device, as a method of actively controlling the output end of the optical fiber laser, Cited Document 1: M.A. Vorontsov, T. Weyrauch et al. "Adaptive array of phase-locked fiber collimators: analysis and experimental demonstration" IEEE journal of selected topics in quantum electronics, 15, 2 (2009). and Citation 2: D. Zhi, Y Ma et al. "Highly efficient coherent conformal projection system based on adaptive fiber optics collimator array" Sci. Rep 9, 2783 (2019) has been introduced.

Reference 1 discloses tilting the tip of the end of an optical fiber using a PZT element. Cited Document 1 is for a low-power laser, and since the high-power laser uses a thicker optical fiber and is packaged in an end cap mechanism, it is difficult to drive by the same method as Cited Document 1.

Reference 2 controls the displacement of the X-Y plane of the optical fiber end cap by using a PZT element. According to the technique of Citation 2, in order to move the bulky and heavy end cap package along the X-Y plane, there is a problem in that the volume and weight of the driving part increase. In the case of beam-combining multi-channel laser beams according to the technique of Reference 2, there is a problem in that a conformal fill factor is increased, so that the efficiency of beam coupling is lowered.

M.A. Vorontsov, T. Weyrauch et al. "Adaptive array of phase-locked fiber collimators: analysis and experimental demonstration" IEEE journal of selected topics in quantum electronics, 15, 2 (2009) D. Zhi, Y Ma et al. "Highly efficient coherent conformal projection system based on adaptive fiber optics collimator array" Sci. Rep 9, 2783 (2019)

The present invention is proposed under the background described above, and proposes an optical fiber directing device capable of redirecting packaging itself, and a laser beam coupling device using the directing device.

The present invention proposes an optical fiber directing device capable of increasing the efficiency of beam coupling by implementing a low conformal fill factor, and a laser beam coupling device using the directing device.

The optical fiber directing device of the present invention includes a piezoelectric element that moves in the z-axis direction in the z-axis; a push structure connected to the piezoelectric element and displaced along the z-axis; an outgoing body through which an optical fiber passes; a direction changer provided on the outside of the emitting body and in contact with the push structure to change the z-axis displacement to a displacement in a direction inclined to the z-axis, so that the emitting body is displaced in the xy direction; a lens provided in front of the exit body; and a restoration body that maintains the position and posture of the exit body.

The direction changer may have a non-orthogonal surface that is not orthogonal to the z-axis direction and can be in contact with the push structure.

The direction changer may be provided with a first direction changer in the y-axis direction and a second direction changer in the x-axis direction.

The first turning device and the second turning device may be installed to be perpendicular to each other at 90 degrees.

The non-orthogonal surface may include an inclined surface or a curved surface as a part.

Supporting the restoration body, the exit body, the push structure and the outside of the piezoelectric element may include a barrel which is provided long in the z-direction.

The push structure may extend long in the z-direction toward the front of the piezoelectric element.

The beam combining device of the present invention comprises: a cradle having at least two recesses in which any one of the optical fiber directing devices is hooked, respectively; and a fixed table having the cradle, wherein the at least two optical fiber directing devices can be synchronized with each other.

A controller for controlling the piezoelectric element may be external to the optical fiber directing device.

According to the present invention, it is possible to change the orientation of the packaging itself in a small volume.

According to the present invention, it is possible to obtain a low conformal fill factor in the optical fiber directing device and the laser beam coupling device. Accordingly, it is possible to realize a laser device having a small volume and high power.

1 is a view for explaining the operation of an optical fiber directing device according to an embodiment.
2 is a view showing a state in which the main part of the optical fiber directing device according to the embodiment is separated.
3 is a view showing a state in which the main parts of the optical fiber directing device according to the embodiment are coupled.
Figure 4 is a view showing the state that the outer cover is fastened to the optical fiber directing device, a is after the barrel is inserted, b is a view showing before the barrel is inserted.
5 is a view showing the configuration of a laser beam coupling device according to the embodiment.
6 is a view for explaining a conformal fill factor (conformal fill factor).

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. However, those skilled in the art who understand the spirit of the present invention will be able to easily suggest other embodiments included within the scope of the same spirit by adding, changing, deleting, and adding components, but this is also the scope of the present invention. will be included in the

The inventors have conceived as follows.

When at least two or more optical fiber directing devices are arranged in two dimensions, in order to increase a fill factor (inter-lens distance/lens size), it is preferable to minimize the mechanical area in the X-Y direction. In addition, it is preferable that the optical fiber directing device can be driven at a high speed at the same time.

In order to satisfy this, it is preferable that the optical fiber directing device be elongated. Preferably, the optical fiber directing device has a light weight.

To this end, by way of example, an actuator (PZT, etc.) that transmits power moves in the longitudinal direction (Z-axis), and the optical fiber end cap is integrated in the X-Y direction by an exemplary X-Y-axis redirector (sloped surface or convex curved surface). Moving may be desirable.

The above-mentioned point was embodied by the following various examples.

1 is a view for explaining the operation of an optical fiber directing device according to an embodiment, FIG. 2 is a view showing a state in which a main part of the optical fiber directing device according to the embodiment is separated, and FIG. 3 is an optical fiber directing device according to the embodiment It is a diagram showing the state in which the main parts of the

1 to 3, the main operation of the optical fiber directing device will be described.

The optical fiber directing device 1 of the embodiment may include an actuator 10 for providing a driving force, and an emitting body 20 for emitting a laser.

The actuator 10 is provided with a driving unit that drives according to a control signal of the controller 60 placed outside. The driving unit may use a piezoelectric element. The piezoelectric element may be deformed by applying a voltage. Lead Zirconate Titanate (PZT) may be used as the piezoelectric element. Hereinafter, referred to as PZT is for convenience of understanding, and various piezoelectric elements may be interpreted as equivalents thereof.

The output body 20 is a structure through which the optical fiber passes, and the displacement of the actuator 10 is changed to change and adjust the output direction of the optical fiber.

In the actuator 10, a rear cover 14 covering the rear, a PZT supporter 13 installed in front of the rear cover, a PZT 11 supported by the PZT supporter, and a push bar 12 extending forward from the PZT ) may be included. The PZT may be deformed in the z-axis direction by an external voltage. The deformation in the z-axis direction may be defined as motion having a predetermined amplitude and period. The push bar may be any push structure capable of pushing by connecting a force, for example, a push plate, a push rope, etc. will be possible.

The PZT supporter 13 , the PZT 11 , and the push bar 12 are a pair for driving the emitting body 20 in the y-axis direction and the emitting body 20 in the x-axis direction. can be provided. In the drawings or embodiments, the subscript y is added after the reference number of the configuration for driving in the y-axis direction. In the following embodiments, descriptions of reference numerals are the same in the description of other components. For example, the same is true for a turn changer.

An end cap 21 through which the optical fiber 30 passes may be fastened to the exit body 20 . The optical fiber 30 may pass through the end cap 21 and the central portion of the emitting body 20 . A lens 22 may be provided at the exit end of the exit body 20 . A barrel (refer to 50 in FIG. 4) may be provided on the outside of the exit body 20 . In addition to the barrel 50, other exterior parts such as a casing may also serve as the barrel.

An empty space may be provided between the exit body 20 and the barrel 50 . Outside the exit body (here, outside may mean outside where the optical fiber is placed), and in the empty space, a structure for controlling the emission direction of the optical fiber, a structure for supporting the position and posture of the emission body 20 , and a position and posture alignment mechanism of the actuator 10 and the exit body 20 may be placed. The actuator 10 and the output body 20 are not coupled as a single body, but may have a structure that allows relative deformation.

First, the structure for controlling the emission direction of the optical fiber may have the following configuration. It may include a direction changer 24 that the push bar 12 can come into contact with, and a push bar holder 23 that guides the operation of the push bar 12 . The z-axis displacement of the push bar 12y may be changed to the y-axis displacement by the first direction changer 24y. For example, the z-axis displacement may be a translation action of the push bar along the z-axis, and the y-axis displacement may be a translation action of the exit body (the output end of the optical fiber) along the y-axis. Referring to Figure 1 (a), it is possible to grasp the operation of each member.

The above description can be applied similarly to the x-axis displacement. That is, the same can be applied to the push bar 12x and the second direction changer 24x.

The deformation by the vector sum of the x-axis displacement and the y-axis displacement may be referred to as an xy displacement.

By the push bars 12x (12y) and the direction changers 24x and 24y, the emitting body 20 can move in any direction with respect to the two-dimensional plane of the xy plane, and the emitting direction of the optical fiber can be adjusted. can For example, when a plurality of optical fiber directing devices are arranged in a concentric circle, the laser device of high power can be obtained by condensing the emitted light by synchronizing to the center of the concentric circle. In this case, the lens 22 may refract the light emitted from the optical fiber to condense the emitted light to a predetermined point. Since the emitted light is refracted differently depending on the contact position of the incident surface of the lens, a plurality of emitted light may be focused on a single point. For example, if the lens is a convex lens, the light emitted through the center may travel in a straight line, and the light emitted through the outside of the center may be refracted toward the center.

The structure supporting the position and posture of the emitting body 20 may have the following configuration. The restoration body 25 may be provided in various directions on the outside of the exit body 20 . The restoration body may be provided between the outside of the exit body 20 and the barrel 50 so that the position and posture of the exit body 20 are supported with respect to parts placed on the outside of the exit body. Accordingly, even if the posture of the exit body is moved by the direction changer, it can be returned to the original position.

The restoration body 25 may include a bearing and an elastic support body. The bearing may be a ball bearing. The bearing may ensure sliding between parts. The elastic support may be restored to its original position when the exit body moves along the xy plane.

The actuator 10 and the position and posture alignment mechanism of the emitting body 20 may have the following configuration. A push bar holder 23 into which the push bar 12 is inserted may be provided. By the push bar holder 23 , buckling of the push bar 12 can be prevented even when the push bar 12 pushes at a high speed. Of course, the actuator and the exit body may be fixed to each other from the outside by the barrel 50 .

The direction changer 24 will be described in detail.

The direction changer 24 may be provided as an inclined surface having a predetermined direction and a gentle curved surface that is inclined to be processed on the outer surface of the exit body 20 . The direction changer may be provided as a non-orthogonal surface (including both curved and inclined surfaces) that is not orthogonal to the extension direction of the push bar 12 or the z-axis direction. According to the embodiment, the first direction changer 24y is provided as an inclined surface that is inclined forward toward the outside of the exit body 20, but is not limited thereto. In the embodiment, the inclination angle is indicated by A1. It may be provided as an inclined surface that is inclined forward toward the inside of the exit body 20 . However, in this case, it is not preferable because more space is required in the exit body to accommodate the inclined surface.

The direction changer 24 may use that the push bar 12 pushes the non-orthogonal surface of the direction changer, and the non-orthogonal surface moves in a direction different from the displacement direction of the push bar 12 . For example, the z-axis displacement of the push bar 12y may be changed to the y-axis displacement by the first direction changer 24y. The z-axis displacement of the push bar 12x may be changed to the x-axis displacement by the second direction changer 24x. The turners may be orthogonal to each other at 90 degrees.

If the number of turners is larger, it may be displaced in several directions perpendicular to the z-axis, in which case more precise turns may be possible. For example, when there are three direction changers, it can be implemented as a displacement given by a vector sum.

As another example, only one direction changer may be provided, and it may be applied to a laser beam combining device arranged in a shooting type.

An example of the direction changer 24 will be described with reference to FIG. 1(b).

If the direction changer 24 is manufactured in an isosceles triangle of 45 degrees and the central part is pushed, the Z-axis displacement and the Y-axis displacement are the same (left), and if the lower part is pushed, the displacement can be further increased (center), and the direction changer If the inclination angle of the non-orthogonal plane is increased, the same Y displacement can be moved even with a smaller Z-axis displacement (right). Smaller PZTs are faster and have lower displacements, but a larger inclination angle embodiment can be beneficial in this case.

According to an embodiment, the volume of the optical fiber directing device increases only by the thickness of the redirector and the actuator, and hardly takes up. The actuator wires can run through the back and connect to the controller. The weight of the controller may not affect the operation of the optical fiber directing device. The adaptive optical fiber directing device may be arranged in two dimensions to constitute a multi-channel output stage.

4 is a view showing a state in which the outer cover is fastened to the optical fiber directing device. a is after the tube is inserted, and b is before the tube is inserted.

Referring to FIG. 4 , the rear actuator 10 and the front end cap holder 27 are placed. The end cap holder 27 has a built-in output body 20 . A long barrel is inserted into the actuator 10 and the end cap holder 27 to maintain an optical path. The end cap holder 27 may hold the end cap 21 to fix its position.

5 is a view showing the configuration of a laser beam coupling device according to the embodiment.

Referring to FIG. 5, the laser beam coupling device includes a fixed table 100 fixed to an external device, and at least two cradles 110 extending from the fixed table and having at least two or more recesses 111 and 121, respectively. ) 120 , and an optical fiber directing device 1 caught in the recess.

At least two of the optical fiber directing devices 1 are provided, synchronized with each other, and the output light can be focused. The number of the optical fiber directing devices, ie, multi-channel output stages, may be 3, 7, 17, 37, or the like. The direction of the multi-channel beam may be controlled using a stochastic parallel gradient descent method (SPGD) algorithm or an artificial intelligence algorithm. The algorithm may be mounted in the controller 60 .

6 is a view for explaining a conformal fill factor.

Referring to FIG. 6 , the conformal fill factor fc may be given as a distance l between lenses/lens size d. In this case, the smaller the conformal fill factor, the higher the efficiency. In other words, a high-power laser device can be realized by disposing a larger number of optical fiber directing devices in a small area.

The present invention can arrange an optical fiber directing device with high density in the z-axis direction, that is, in the xy plane. Accordingly, the efficiency of the laser beam coupling device can be increased. The present invention can be widely used in industries requiring high-density and high-power lasers.

10: actuator
20: exit body
24: turn changer

Claims (8)

a piezoelectric element that moves in the z-axis direction in the z-axis direction;
a push structure connected to the piezoelectric element and displaced along the z-axis;
an outgoing body through which an optical fiber passes;
a direction changer provided on the outside of the emitting body and in contact with the push structure to change the z-axis displacement to a displacement in a direction inclined to the z-axis, so that the emitting body is displaced in the xy direction;
a lens provided in front of the exit body; and
A restoration body for maintaining the position and posture of the exit body is included,
The direction changer is not orthogonal to the z-axis direction, the optical fiber directing device having a non-orthogonal surface that can be in contact with the push structure. The method of claim 1,
The turning device is an optical fiber pointing device provided with a first turner in the y-axis direction and a second turner in the x-axis direction. 3. The method of claim 2,
The first direction changer and the second direction changer are installed to be perpendicular to each other at 90 degrees. The method of claim 1,
The non-orthogonal surface is an inclined surface or a curved surface. The method of claim 1,
An optical fiber directing device that supports the restoration body and includes a barrel extending in the z-direction from the outside of the emitting body, the push structure, and the piezoelectric element. The method of claim 1,
The push structure is an optical fiber directing device extending long in the z direction in front of the piezoelectric element. [7] A holder having at least two recesses through which the optical fiber directing device of any one of claims 1 to 6, respectively;
A fixed table having the cradle is included,
wherein the at least two optical fiber directing devices are synchronized with each other. 8. The method of claim 7,
A controller for controlling the piezoelectric element is placed outside the optical fiber directing device.

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