A collimation system for an optical fiber end cap and its collimation test method

Abstract

The present invention discloses a collimation system for an optical fiber end cap and a collimation test method thereof. A helium-neon laser can generate helium-neon light. An optical fiber end cap and an aspherical mirror are respectively installed at the two ends of the barrel of the lens barrel, and an optical path is formed between the barrel cavity of the lens barrel and the output end of the helium-neon laser. A first CCD is disposed between the first mirror frame and the optical fiber end cap assembly, and the first CCD has an imaging film. The helium-neon light beam can form a spot image on the imaging film. A first aperture stop is disposed on one side of the optical fiber end cap assembly. The first aperture stop has an aperture stop hole, and the aperture stop hole of the first aperture stop is located on the optical path. A second aperture stop is disposed between the helium-neon laser and the first CCD. The first aperture stop has an aperture stop hole, and the aperture stop hole of the second aperture stop is located on the optical path. The beam quality of the laser output is ensured.

Description

Technical Field

[0001] The present invention belongs to the field of laser testing, and particularly relates to a collimation system for an optical fiber end cap and a collimation testing method therefor. Background Art

[0002] With the maturity of laser processing technology and the popularization of its applications, fiber lasers play an irreplaceable role in fields such as industrial processing, material treatment, 3D printing, and national defense security. In order to achieve better processing quality and higher processing speed, laser manufacturers continuously pursue and challenge higher power, better beam quality, higher pulse energy, and more convenient operation control methods.

[0003] A relatively large quartz block is fusion-spliced to the end face of an optical fiber to form an optical fiber end cap, and at the same time, an antireflection film is processed on the output surface of the quartz block to achieve the safe output of high-power narrow-pulse-width fiber lasers. Since the optical fiber end cap is installed in the system, the laser beam passing through the optical fiber end cap cannot be guaranteed to emit parallelly, resulting in the inability to guarantee the beam quality of the output of the optical fiber end cap. Therefore, how to collimate the optical fiber end cap has become a technical problem that urgently needs to be solved. Summary of the Invention

[0004] The purpose of the present invention is to provide a collimation system for an optical fiber end cap and a collimation testing method therefor to ensure the beam quality of the output of the optical fiber end cap.

[0005] The present invention provides a collimation system for an optical fiber end cap, which includes:

[0006] A helium-neon laser that can generate helium-neon light, and the helium-neon laser has an output end that can emit a helium-neon light beam.

[0007] An optical fiber end cap assembly, which includes a mounting seat having a mounting hole, and a lens barrel is provided in the mounting hole. An optical fiber end cap and an aspherical mirror are respectively installed at both ends of the lens barrel, and an optical path is formed between the barrel cavity of the lens barrel and the output end of the helium-neon laser.

[0008] A first mirror mount, which includes a reflecting mirror, and the reflecting mirror of the first mirror mount is disposed on the optical path. The reflecting mirror of the first mirror mount can reflect the helium-neon light beam into the barrel cavity of the lens barrel.

[0009] A second mirror mount, which is disposed between the helium-neon laser and the first mirror mount, and the second mirror mount has a reflecting mirror. The second mirror mount can adjust the reflecting mirror to reflect the helium-neon light beam onto the reflecting mirror of the first mirror mount.

[0010] A first CCD, which is disposed between the first mirror mount and the optical fiber end cap assembly, and the first CCD has an imaging chip. The helium-neon light beam can form a spot image on the imaging chip.

[0011] A first diaphragm, which is arranged on one side of the fiber end cap assembly. The first diaphragm has a diaphragm hole, and the diaphragm hole of the first diaphragm is located on the optical path.

[0012] A second diaphragm, which is arranged between the helium-neon laser and the first CCD. The second diaphragm has a diaphragm hole, and the diaphragm hole of the second diaphragm is located on the optical path.

[0013] Furthermore, the collimation system of the fiber end cap further includes: a second CCD, which has an imaging plate. The imaging plate of the second CCD is arranged between the second mirror holder and the fiber end cap assembly. The helium-neon light beam can form a spot image on the imaging plate of the second CCD.

[0014] Furthermore, the fiber end cap includes a pigtail and a end cap. The end cap is frustum-shaped and has a small-diameter end face and a large-diameter end face. The small-diameter end face of the end cap is fused to one end of the pigtail.

[0015] The pigtail is fixed by a fiber fixing block and a fiber cover, and the other end of the pigtail is connected to the fiber interface of the beam combiner.

[0016] Furthermore, the fiber end cap assembly includes: a base, and the base is connected to the mounting seat. A lens barrel is arranged in the mounting hole of the mounting seat, and the inner cavity of the lens barrel is a stepped hole.

[0017] A rotating ring is arranged in the large-diameter section at one end of the lens barrel. The rotating ring is connected to an aspheric mirror, and the aspheric mirror is fixed by a PTFE washer and a retaining ring. The rotation center line of the rotating ring is eccentrically arranged with the aspheric mirror, and the rotating ring can drive the aspheric mirror to rotate.

[0018] A rotating circle is sleeved outside the small-diameter section at the other end of the lens barrel. A fiber metal sleeve is arranged in the small-diameter section, and the rotating circle is connected to the fiber metal sleeve. The rotation center line of the rotating circle coincides with the axis center line of the fiber end cap in the fiber metal sleeve. The rotating circle can drive the fiber end cap to rotate synchronously, and the rotating circle and the mounting seat are locked by screws.

[0019] The present invention also provides a collimation test method for the collimation system of the fiber end cap, which includes:

[0020] S101: Install an aluminized film on the mirror of the first mirror holder and install a dichroic mirror on the second mirror holder. Adjust the mirror of the first mirror holder and the dichroic mirror of the second mirror holder to the target height.

[0021] S102: Adjust the diaphragm holes of the first diaphragm and the second diaphragm to the target height.

[0022] S103: Adjust the pitch and horizontal knobs of the mirror of the first mirror holder so that the helium-neon light is transmitted along the optical path, and move the second diaphragm back and forth to adjust the helium-neon light reflected by the mirror of the first mirror holder to the target height.

[0023] S104: Repeat S103 to enable the helium-neon beam to pass through the center of the aperture of the first aperture, and determine that the height of the helium-neon light in the entire optical path is adjusted to the target height.

[0024] S105: Adjust the base of the fiber optic end cap assembly to enable the helium-neon light to pass through the center of the fiber optic metal sleeve, and adjust the position of the first CCD to make the helium-neon beam hit the center of the first CCD and form a circular spot image, thus completing the collimation test of the collimation system.

[0025] Furthermore, the collimation test method further includes:

[0026] S201: Weld the end cap and the pigtail to form a fiber optic end cap, install the fiber optic end cap in the fiber optic metal sleeve, and fix the pigtail with a fiber optic fixing block and a fiber optic cover.

[0027] S202: Install the aspheric mirror in the rotating ring and fix it to the rotating ring with a PTFE washer and a lens retaining ring.

[0028] S203: Connect the pigtail to the beam combiner. The laser generated by the beam combiner enters from the pigtail and outputs from the end cap. Rotate the rotating ring to synchronously rotate the fiber optic metal sleeve until the diameter of the spot on the second CCD is the same as the diameter φ of the large-diameter end face of the end cap. Lock the fixing screw between the rotating ring and the lens barrel.

[0029] S204: Loosen the fixing screw between the rotating ring and the lens barrel, rotate the rotating ring to drive the fiber optic metal sleeve to rotate, and record the change of the center point of the laser spot through the second CCD.

[0030] S205: Adjust the eccentricity of the rotating ring. When the spot hits the center of the second CCD, fix the rotating ring and the lens barrel to complete the collimation test of the fiber optic end cap.

[0031] In the collimation system based on the fiber optic end cap in the present invention, by performing a collimation test on the collimation system of the end cap assembly, the beam quality of the output of the fiber optic end cap is improved. Brief Description of the Drawings

[0032] Figure 1 It is a schematic diagram of the collimation test system of the present invention.

[0033] Figure 2 It is a schematic diagram of the fiber optic end cap assembly of the present invention.

[0034] Figure 3 It is a side view of the fiber optic end cap of the present invention. Detailed Embodiments

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0036] AsFigure 1 As shown, the dotted arrow in the figure indicates the direction of the light beam emitted. The present invention provides a collimation system for an optical fiber end cap, which includes:

[0037] A helium-neon laser 10, which can generate helium-neon light. The helium-neon laser 10 has an output end, and the output end can emit a helium-neon light beam.

[0038] An optical fiber end cap assembly 20, which includes a mounting base 21. The mounting base 21 has a mounting hole, and a lens barrel 24 is arranged in the mounting hole. An optical fiber end cap and an aspherical mirror 26 are respectively installed at both ends of the lens barrel 24. An optical path is formed between the cavity of the lens barrel 24 and the output end of the helium-neon laser 10.

[0039] A first mirror holder 31, which includes a reflecting mirror. The reflecting mirror of the first mirror holder 31 is arranged on the optical path. The reflecting mirror of the first mirror holder 31 can reflect the helium-neon light beam into the cavity of the lens barrel.

[0040] A second mirror holder 32, which is arranged between the helium-neon laser 10 and the first mirror holder 31. The second mirror holder 32 has a reflecting mirror, and the second mirror holder 32 can adjust the reflecting mirror so that the helium-neon light beam is reflected onto the reflecting mirror of the first mirror holder 31.

[0041] A first CCD 41, which is arranged between the first mirror holder 31 and the optical fiber end cap assembly 20. The first CCD 41 has an imaging film. The helium-neon light beam can form a spot image on the imaging film.

[0042] A first diaphragm 51, which is arranged on one side of the optical fiber end cap assembly 20. The first diaphragm 51 has a diaphragm hole, and the diaphragm hole of the first diaphragm 51 is located on the optical path.

[0043] A second diaphragm 52, which is arranged between the helium-neon laser 10 and the first CCD 41. The first diaphragm 51 has a diaphragm hole, and the diaphragm hole of the second diaphragm 52 is located on the optical path.

[0044] The helium-neon laser 10 is a gas laser with neutral atomic gases helium and neon as the working substances. The helium-neon light beam is output in a continuous excitation mode.

[0045] The following is the collimation test method for the collimation system in the present invention, which includes:

[0046] S101: An aluminized film is installed on the reflecting mirror of the first mirror holder 31, and a dichroic mirror is installed on the second mirror holder 32. Adjust the reflecting mirror of the first mirror holder 31 and the dichroic mirror of the second mirror holder 32 to the target height.

[0047] S102: Adjust the diaphragm holes of the first diaphragm 51 and the second diaphragm 52 to the target height.

[0048] S103: Adjust the pitch and horizontal knobs of the mirror of the first mirror frame 31 to make the helium-neon light transmit along the optical path, and move the second diaphragm 52 back and forth to adjust the helium-neon light reflected by the mirror of the first mirror frame 31 to the target height.

[0049] S104: Repeat S103 to make the helium-neon light beam pass through the center of the aperture of the first diaphragm 51, and determine that the height of the helium-neon light in the entire optical path is adjusted to the target height.

[0050] S105: Make the helium-neon light pass through the center of the fiber metal sleeve 28 by adjusting the base of the fiber optic end cap assembly 20, and adjust the position of the first CCD 41 so that the helium-neon light beam hits the center of the first CCD 41 and forms a circular spot image, completing the collimation test of the collimation system.

[0051] It should be noted that in S105, the fiber optic end cap and the aspherical mirror 26 are not installed so that the helium-neon light passes through the center of the fiber metal sleeve 28.

[0052] For example, if the target height is 100 mm, adjust the mirror of the first mirror frame 31 and the dichroic mirror of the second mirror frame 32 to 100 mm, then adjust the apertures of the first diaphragm 51 and the second diaphragm 52 to 100 mm, adjust the pitch and horizontal knobs of the mirror of the first mirror frame 31 to make the helium-neon light transmit along the optical path, move the second diaphragm 52 back and forth to adjust the helium-neon light reflected by the mirror of the first mirror frame 31 to 100 mm, adjust the position of the first CCD 41 so that the helium-neon light beam hits the center of the first CCD 41 and forms a circular spot image, completing the collimation test of the collimation system. The above steps are to prepare for the collimation of the fiber optic end cap to ensure that the fiber optic end cap can be collimated after installation.

[0053] Charge-coupled Device (CCD for short) can be called a CCD image sensor or an image controller. A CCD is a semiconductor device that can convert an optical image into an electrical signal. The tiny photosensitive substances implanted on the CCD are called pixels (Pixels). The more pixels a CCD contains, the higher the resolution of the picture it provides. The function of a CCD is like that of film, but it converts the optical signal into a charge signal. There are many neatly arranged photodiodes on the CCD that can sense light and convert the optical signal into an electrical signal, which is then converted into a digital image signal through an external sampling amplifier and analog-to-digital conversion circuit.

[0054] A diaphragm refers to an entity that restricts the light beam in an optical system. It can be the edge of a lens, a frame, or a specially set perforated screen. The diaphragm is used to limit the size of the light beam.

[0055] Such as Figure 2As shown in the figure, the fiber optic end cap assembly 20 includes: a base 22, and the base 22 is connected to the mounting base 21. A lens barrel 24 is arranged in the mounting hole 23 of the mounting base 21, and the inner cavity of the lens barrel 24 is in the shape of a stepped hole.

[0056] A rotating ring 25 is arranged in the large-diameter section at one end of the lens barrel 24. The rotating ring 25 is connected to the aspherical mirror 26. The aspherical mirror 26 is fixed by a PTFE gasket and a retaining ring. The rotation center line of the rotating ring 25 is eccentrically arranged with respect to the aspherical mirror 26, and the rotating ring 25 can drive the aspherical mirror 26 to rotate.

[0057] A rotating ring 27 is sleeved outside the small-diameter section at the other end of the lens barrel 24. A fiber optic metal sleeve 28 is arranged in the small-diameter section. The rotating ring 27 is connected to the fiber optic metal sleeve 28. The rotation center line of the rotating ring 27 coincides with the axis core line of the fiber optic end cap in the fiber optic metal sleeve 28. The rotating ring 27 can drive the fiber optic end cap to rotate synchronously, and the rotating ring 27 and the mounting base 21 are locked by screws.

[0058] By arranging a rotating ring 25 in the large-diameter section at one end of the lens barrel 24 and sleeving a rotating ring 27 outside the small-diameter section at the other end of the lens barrel 24, the rotating ring 25 and the rotating ring 27 can respectively adjust the aspherical mirror 26 and the fiber optic end cap in the fiber optic metal sleeve 28 to ensure that the fiber optic end cap can be quickly collimated.

[0059] As Figure 3 shown in the figure, the fiber optic end cap includes a pigtail 2 and an end cap 1. The end cap 1 is in the shape of a frustum of a cone. The end cap 1 has a small-diameter end face 11 and a large-diameter end face 12. The small-diameter end face 11 of the end cap 1 is fused to one end of the pigtail 2.

[0060] The pigtail 2 is fixed by a fiber optic fixing block 13 and a fiber optic cover 14. The other end of the pigtail 2 is connected to the fiber optic interface of the beam combiner.

[0061] The collimation system of the fiber optic end cap in the present invention further includes: a second CCD 42, which has an imaging chip. The imaging chip of the second CCD 42 is arranged between the second mirror holder 32 and the fiber optic end cap assembly 20. The helium-neon beam can form a spot image on the imaging chip of the second CCD 42.

[0062] By additionally arranging the second CCD 42, it is convenient to collimate the fiber optic end cap.

[0063] The collimation test method of the present invention further includes:

[0064] S201: Fuse the end cap 1 and the pigtail 2 to form a fiber optic end cap, install the fiber optic end cap in the fiber optic metal sleeve 28, and fix the pigtail 2 with the fiber optic fixing block 13 and the fiber optic cover 14.

[0065] S202: Install the aspherical mirror 26 in the rotating ring 25 and fix it on the rotating ring 25 with a PTFE gasket and a lens retaining ring.

[0066] S203: Connect the pigtail fiber 2 to the beam combiner. The laser generated by the beam combiner enters through the pigtail fiber 2 and outputs from the end cap 1. Rotate the turntable 27 to synchronously rotate the fiber metal sleeve 28 until the diameter of the light spot on the second CCD 42 is the same as the diameter φ of the large-diameter end face 12 of the end cap 1. Lock the fixing screw between the turntable 27 and the lens barrel 24.

[0067] S204: Loosen the fixing screw between the rotating ring 25 and the lens barrel 24, rotate the rotating ring 25 to drive the fiber metal sleeve 28 to rotate, and record the change of the center point of the laser light spot through the second CCD 42.

[0068] S205: Adjust the eccentricity of the aspheric mirror 26 on the rotating ring 25. When the light spot hits the center of the second CCD 42, fix the rotating ring 25 and the lens barrel 24 to complete the collimation test of the fiber end cap.

[0069] For example, the diameters of the small-diameter end face 11 and the large-diameter end face 12 of the end cap 1 are 0.8 mm and 3 mm respectively. First, rotate the turntable 27 to synchronously rotate the fiber metal sleeve 28 until the diameter of the light spot on the second CCD 42 is the same as the diameter 3 mm of the large-diameter end face 12 of the end cap 1. Lock the fixing screw between the turntable 27 and the lens barrel 24.

[0070] Then, since the rotation center line of the rotating ring 25 is eccentrically arranged with the aspheric mirror 26, by rotating the rotating ring 25 to adjust the eccentricity of the aspheric mirror 26, when the light spot can hit the center of the second CCD 42, fix the rotating ring 25 and the lens barrel 24 to complete the collimation test of the fiber end cap, and ensure the beam quality of the output of the fiber end cap after the collimation of the fiber end cap is completed.

Claims

1. A collimation system for an optical fiber end cap, characterized in that, It includes: A helium-neon laser (10) capable of generating helium-neon light. The helium-neon laser (10) has an output end that can emit a helium-neon light beam; An optical fiber end cap assembly (20) including a mounting base (21) having a mounting hole in which a lens barrel (24) is provided. Fiber end caps and an aspherical mirror (26) are respectively mounted at both ends of the lens barrel (24). An optical path is formed between the cavity of the lens barrel (24) and the output end of the helium-neon laser (10). The optical fiber end cap includes a pigtail (2) and an end cap (1). The end cap (1) is frustum-shaped with a small-diameter end face (11) and a large-diameter end face (12). The small-diameter end face (11) of the end cap (1) is fusion-spliced to one end of the pigtail (2). The pigtail (2) is fixed by an optical fiber fixing block (13) and an optical fiber cover (14), and the other end of the pigtail (2) is connected to the optical fiber interface of the beam combiner; A first mirror mount (31) including a reflecting mirror. The reflecting mirror of the first mirror mount (31) is disposed on the optical path. The reflecting mirror of the first mirror mount (31) can reflect the helium-neon light beam into the cavity of the lens barrel; A second mirror mount (32) disposed between the helium-neon laser (10) and the first mirror mount (31). The second mirror mount (32) has a reflecting mirror and can adjust the reflecting mirror to reflect the helium-neon light beam onto the reflecting mirror of the first mirror mount (31); A first CCD (41) disposed between the first mirror mount (31) and the optical fiber end cap assembly (20). The first CCD (41) has an imaging chip. The helium-neon light beam can form a spot image on the imaging chip; A first aperture (51) disposed on one side of the optical fiber end cap assembly (20). The first aperture (51) has an aperture hole, and the aperture hole of the first aperture (51) is located on the optical path; A second aperture (52) disposed between the helium-neon laser (10) and the first CCD (41). The first aperture (51) has an aperture hole, and the aperture hole of the second aperture (52) is located on the optical path; A second CCD (42) having an imaging chip. The imaging chip of the second CCD (42) is disposed between the second mirror mount (32) and the optical fiber end cap assembly (20). The helium-neon light beam can form a spot image on the imaging chip of the second CCD (42); The optical fiber end cap assembly (20) includes: A base (22) connecting the mounting base (21). A lens barrel (24) is provided in the mounting hole (23) of the mounting base (21), and the inner cavity of the lens barrel (24) is in the shape of a stepped hole; A swivel ring (25) is provided in the large-aperture section at one end of the lens barrel (24). The swivel ring (25) is connected to an aspherical mirror (26). The aspherical mirror (26) is fixed by a PTFE washer and a retaining ring. The rotation center line of the swivel ring (25) is eccentrically arranged with respect to the aspherical mirror (26), and the swivel ring (25) can drive the aspherical mirror (26) to rotate; A rotating ring (27) is sleeved outside the small-aperture section at the other end of the lens barrel (24); an optical fiber metal sleeve (28) is provided in the small-aperture section, and the rotating ring (27) is connected to the optical fiber metal sleeve (28); the rotation center line of the rotating ring (27) coincides with the axis core line of the optical fiber end cap in the optical fiber metal sleeve (28). The rotating ring (27) can drive the optical fiber end cap to rotate synchronously, and the rotating ring (27) and the mounting seat (21) are locked by screws.

2. A collimation test method for a collimation system according to claim 1, characterized in that S101: An aluminized film is installed on the reflecting mirror of the first mirror holder (31), and a dichroic mirror is installed on the second mirror holder (32); the reflecting mirror of the first mirror holder (31) and the dichroic mirror of the second mirror holder (32) are adjusted to the target height; S102: The aperture holes of the first aperture (51) and the second aperture (52) are adjusted to the target height; S103: Adjust the pitch and horizontal knobs of the reflecting mirror of the first mirror holder (31) so that the helium-neon light is transmitted along the optical path, and move the second aperture (52) back and forth to adjust the helium-neon light reflected by the reflecting mirror of the first mirror holder (31) to the target height; S104: Repeat S103 so that the helium-neon light beam passes through the center of the aperture hole of the first aperture (51), and determine that the height adjustment of the helium-neon light in the entire optical path is the target height; S105: By adjusting the base of the optical fiber end cap assembly (20), the helium-neon light is made to pass through the center of the optical fiber metal sleeve (28), and the position of the first CCD (41) is adjusted so that the helium-neon light beam hits the center of the first CCD (41) and forms a circular spot image, completing the collimation test of the collimation system.

3. The collimation test method according to claim 2, wherein It further includes: S201: The fusion splice end cap (1) and the pigtail (2) are fused to form an optical fiber end cap, and the optical fiber end cap is installed in the optical fiber metal sleeve (28), and the pigtail (2) is fixed by an optical fiber fixing block (13) and an optical fiber cover (14); S202: The aspherical mirror (26) is installed in the swivel ring (25) and fixed to the swivel ring (25) with a PTFE washer and a lens retaining ring; S203: The pigtail (2) is connected to the beam combiner. The laser generated by the beam combiner enters from the pigtail (2), and the laser is output from the end cap (1). Rotate the rotating ring (27) so that the optical fiber metal sleeve (28) rotates synchronously until the diameter of the spot on the second CCD (42) is the same as the diameter (φ) of the large-diameter end face (12) of the end cap (1); lock the fixing screw between the rotating ring (27) and the lens barrel (24); S204: Loosen the fixing screw between the swivel ring (25) and the lens barrel (24), rotate the swivel ring (25) to drive the optical fiber metal sleeve (28) to rotate, and record the change of the laser spot center point through the second CCD (42); S205: Adjust the eccentricity of the swivel ring (25). When the light spot hits the center of the second CCD (42), fix the swivel ring (25) and the lens barrel (24) to complete the collimation test of the fiber optic end cap.

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