Processing method of optical fiber microstructure

Abstract

The invention discloses a processing method of an optical fiber microstructure, which comprises the following steps: laser emitted by a laser light source enters an optical modulator after beam expansion, phase compensation is carried out on aberration introduced by an optical fiber structure in advance when the laser passes through the optical modulator, and the laser is focused on an optical fiber after phase compensation, the optical fiber is subjected to material ablation or modification under the action of strong laser, and optical fiber microstructure processing can be realized directly or through wet etching and other processes. The optical fiber microstructure processing method provided by the invention has the beneficial effects that the aberration introduced by the columnar or microporous structure of the optical fiber can be corrected without immersing the processed optical fiber into the refractive index matching liquid, and the processing precision of the microstructure is improved.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber processing, and in particular to a laser processing method for an optical fiber microstructure. Background Art

[0002] When laser direct writing is used to process optical fiber microstructures, the cylindrical shape of standard single-mode or multi-mode optical fibers or the polygonal shape and internal porous structure of special optical fibers cause aberrations in the focused light spot, resulting in inaccurate processing. The aberrations can be corrected by immersing the optical fiber in a refractive index matching liquid, but this method not only pollutes the optical fiber and complicates the manufacturing system and process, but more importantly, different refractive index matching liquids need to be replaced when processing optical fibers of different materials. The matching liquid has a low processing threshold and large laser energy loss, which limits the improvement of processing accuracy. Therefore, it is of great significance to study a high-precision optical fiber microstructure processing method with a flexible and controllable processing system, stable process, and no pollution. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] Based on the above problems, the present invention provides a method for processing optical fiber microstructures, which can non-pollutingly, flexibly and accurately compensate for the aberration of the focused light beam introduced by the optical fiber structure, control the distribution of the focused light field, and improve the processing accuracy of the optical fiber microstructure.

[0005] (II) Technical solution

[0006] Based on the above technical problems, the present invention provides a method for processing optical fiber microstructures, which adopts the following technical solutions:

[0007] S1, the laser emitted by the laser light source is incident on the optical modulator loaded with phase information introduced by the compensation fiber structure after being expanded by the 4f optical system;

[0008] S2, the light beam is shaped by the optical modulator and then irradiated to the processing area of ​​the optical fiber through the focusing light path;

[0009] S3. The optical fiber material is ablated or modified under the action of focused laser, and the optical fiber microstructure can be processed directly or through processes such as wet etching.

[0010] Furthermore, the optical modulator is reflective or transmissive.

[0011] Furthermore, the loaded phase information includes but is not limited to an optical modulator compensation phase, a diffraction grating phase, a focusing mirror phase, and an optical fiber structure compensation phase.

[0012] Furthermore, the focusing light path includes but is not limited to a reflector and a lens.

[0013] (III) Beneficial effects

[0014] The benefit of the present invention lies in that the provided optical fiber microstructure processing method does not require the introduction of optical fibers immersed in refractive index matching liquid. The control of the optical modulation device can correct the processing aberrations introduced by the inherent structures of various optical fibers without pollution, reduce the requirements for optical fiber positioning, improve processing accuracy, and is flexible, simple, reliable and cost-effective to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the present invention in any way. In the accompanying drawings:

[0016] Figure 1 A schematic diagram of a processing laser beam control process method of the present invention;

[0017] Figure 2 To adopt Figure 1 Schematic diagram of the fiber microstructure laser processing device of the process method;

[0018] 10: laser light source; 20: first lens; 21: second lens; 22: third lens; 23: fourth lens; 24: fifth lens; 25: sixth lens; 30: optical modulator; 40: first reflector; 50: aperture; 60: dichroic mirror; 70: five-dimensional precision motion platform; 80: first fiber clamp; 81: second fiber clamp; 90: optical fiber to be processed; 100: computer; 110: first CCD; 111: second CCD. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figure 1 As shown, the present invention provides a processing method: a laser processing method for optical fiber microstructure, the laser emitted by the laser light source is beam-shaped after beam expansion, and then undergoes Fourier transformation, and a suitable diffraction order (usually set to the 1st diffraction order) is selected at the focal plane to pass through, and then the laser is focused to the surface or inside of the optical fiber through a focusing system.

[0021] like Figure 2 As shown, the optical path part of the optical fiber microstructure processing device includes a laser light source 10, a first lens 20, a second lens 21, a spatial light modulator 30, a first reflector 40, a third lens 22, an aperture 50, a fourth lens 23, a dichroic mirror 60, and a fifth lens 24.

[0022] The clamping and positioning system of the optical fiber 90 to be processed includes a first optical fiber clamp 80 , a second optical fiber clamp 81 , and a five-dimensional precision motion platform 70 .

[0023] The positioning observation system of the optical fiber 90 to be processed includes a fifth lens 24, a first CCD 110, a sixth lens 25, and a second CCD 111. The laser light source 10, the spatial light modulator 30, the five-dimensional precision motion platform 70, the first CCD 110, and the second CCD 111 are all controlled by a computer 100.

[0024] Specifically, the computer 100 controls the laser light source 10 to emit a laser output with a wavelength of 800 nm, a pulse width of 120 fs, an average power of 100 mW, and a spot radius of 13 mm.

[0025] The light beam passes through a first lens 20 with a focal length of 100 mm and a second lens 21 with a focal length of 500 mm. The distance between the first lens 20 and the second lens 21 is 600 mm, and the beam radius is expanded to 65 mm.

[0026] The center of the beam after expansion is irradiated to the center of the liquid crystal panel of the reflective spatial light modulator 30. The spatial light modulator 30 is controlled by the computer 100, and the liquid crystal panel compensation phase of the spatial light modulator, the cylindrical lens phase and the blazed grating phase are loaded, and the phase of the beam is modulated. The liquid crystal panel compensation phase of the spatial light modulator is used to compensate for the phase introduced by the spatial light modulator itself, the cylindrical lens phase is used to compensate in advance for the aberration introduced by the cylindrical structure of the optical fiber to the transmission of the focused beam, and the blazed grating is used to separate the zero-order light and the first-order light.

[0027] The modulated light beam is reflected by the first reflector 40 and enters the third lens 22 with a focal length of 500 mm for Fourier transformation. The light beams of different levels are focused on the image focal plane of the third lens 22 to form separate light spots.

[0028] The aperture and position of the aperture 50 on the image-side focal plane of the third lens 22 are adjusted to select the first-order diffraction beam to pass through.

[0029] The fourth lens 23 with a focal length of 300 mm and a distance of 300 mm from the image focal plane of the third lens 22 is used to reduce the spot radius of the first-order diffraction beam.

[0030] When the first-order diffraction beam is directly 20 mm long, it is reflected by the dichroic mirror 60 which totally reflects the 800 nm light and transmits the visible light, and enters the fifth lens 24 with a focal length of 10 mm, thereby being focused.

[0031] The optical fiber 90 is fixed to the five-dimensional precision motion platform 70 by a first optical fiber clamp 80 and a second optical fiber clamp 81 .

[0032] A portion of the visible light irradiated to the optical fiber 90 is focused on the first CCD 110 via the fifth lens 24 and the dichroic mirror 60, and an image is outputted on the computer 100 for observing the position and posture of the optical fiber 90 in the xz plane.

[0033] A portion of the visible light irradiated to the optical fiber 90 is focused on the second CCD 111 through the sixth lens 25 with a focal length of 10 mm, and an image is output on the computer 100 for observing the position and posture of the optical fiber 90 in the yz plane.

[0034] The computer 100 controls the five-dimensional precision motion platform 70 to adjust the position and posture of the optical fiber 90 so that the optical fiber processing area coincides with the focus formed by the first-order diffraction beam after passing through the fifth lens 24, thereby realizing the processing of the optical fiber microstructure.

[0035] This method can correct the aberration introduced by the optical fiber structure to be processed in a pollution-free and flexible manner, control the distribution of the focused light field, and improve the processing accuracy of the optical fiber microstructure.

Claims

1. A method for processing an optical fiber microstructure, characterized in that: When the processing laser passes through the optical modulator, it pre-phase compensates for the aberration introduced by the optical fiber structure and then focuses the processing optical fiber to ablate or modify the material. The optical fiber microstructure processing can be achieved directly or through processes such as wet etching.

2. The optical fiber microstructure processing method according to claim 1, characterized in that: The following steps are involved: S1, the laser emitted by the laser light source is incident on the optical modulator loaded with specific phase information after being expanded by the 4f optical system; S2, the light beam is modulated by an optical modulator and irradiated to the processing area of ​​the optical fiber through a focusing light path; S3. The optical fiber material is ablated or modified under the action of focused laser, and the optical fiber microstructure can be processed directly or through processes such as wet etching.

3. A method for processing optical fiber microstructure according to claim 1, 2, characterized in that: The optical modulator is reflective or transmissive.

4. A method for processing optical fiber microstructure according to claim 1, 2, characterized in that: The loaded phase information includes but is not limited to modulator compensation phase, diffraction grating phase, focusing mirror phase, and optical fiber structure compensation phase.

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