TW561285B - Manufacturing method of fiber collimator - Google Patents

Abstract

The present invention relates to a manufacturing method of fiber collimator, which is composed of an external casing pipe having a washer therein and an aspherical lens. The manufacturing method comprises the steps of: providing an external casing pipe having a washer therein, in which the thickness of the washer is designed to be equal to or larger than the effective focus length of the aspherical lens in considering the tolerance of the mechanical processing, and the difference is preferably less than 30 mum; providing a fiber head having an external diameter designed to be the same as the inner diameter of the external casing pipe for being inserted into the external casing pipe to abut on the first terminal face of the washer and fix the same; providing an aspherical lens having an external diameter designed to be the same as the inner diameter of the external casing pipe for being inserted into the external casing pipe to abut on the second terminal face of the washer and fix the same, and detecting the effective focus length by the wavelength of the light; enabling the distance Deltad of the fiber terminal away from the focus point to be randomly in the range of 30 mum >= Deltad >= 0 based on that the length of each washer varies according to the tolerance of the mechanical processing, so that the optimal working distance of each fiber collimator is also randomly in the range of 0 mm to 140 mm, and using an optical instrument to detect the working distance of each fiber collimator that has been set; and dividing the working distance into several classes from 0 mm to 140 mm, and screening the fiber collimators by classes according to their working distances for being easily selected by various devices of different working distances. The working distance of the fiber collimator system manufactured by the method of the present invention is randomly to be various kinds of specification in the range of 0 mm to 140 mm, and keeps the insertion loss to be less than 0.15 dB. In the actual assembling process, the optical adjustment process is not required, while only the different working distances caused by the tolerance of mechanical processing are screened by classes in the post stage of detecting the optical beam quality, thereby greatly reducing the manufacturing cost and avoiding the manufacture problem in that time-consuming and laborious optical adjustment has to be performed according to a designated specification in the conventional skill, so as to promote the optical performance and increase the application range applied in a device of long working distance.

Description

561285 V. Description of the invention (1) The present invention provides an optical fiber collimator system, using an outer sleeve with a washer inside and an illegal ’, especially one

Lens) to form an optical fiber collimator, and make = (Spherical head can be sleeved in the outer sleeve and tightly fixed to the lens and-the optical fiber difference can randomly generate a variety of different good: = mechanical processing company, 'in optical communications Of the components, it is often necessary to parallelize the expanded beam transmitted in the optical fiber, pass through some functional components, and then continue the transmission wheel. The part that plays this role is = Fiber Colllmator; and the fiber optic standard The collimator system includes two pairs of optical fiber collimators. One optical fiber collimator can collimate the outgoing beam with a certain divergence angle (NA.). After collimating the beam by the collimating lens, after the working distance of the system, Another fiber collimator collimates the beam and couples it back into the fiber. The working distance is used to place various functional parts. The optimal working distance range of a & fiber collimator system is two fiber collimators. Parallel beams between collimators can maintain parallelism and maintain the distance between the two fiber collimators at the lowest insertion loss of the system. 'Also known as Fiber Col 1 imator Manufacturing technology, such as As shown in the figure, the optical fiber collimator uses a glass tube (Glass Tube) with a smooth inner diameter, and an outer diameter (Outer Diameter (〇.Ι) ·) is fixed in the sleeve 11 and the inside of the sleeve. Diameter (inne; r Diameter, I · D ·) of the same fiber head 1 2 (or pin), used to locate the optical fiber 1 3, and a graded index (GRIN) lens (or GRIN -type lens) 14 for parallelizing the beam of fiber 13 or

561285 V. Description of the invention (2) The parallel beam is coupled back to another secret clerk ^ ^ ^ ^ ^ ^ ^ ^ ^… first in the fiber, and a stainless steel sleeve 15 is coated on the outside of the glass sleeve 11 as a 徭婊 Ｍ 泊 u Set, w, Qiaohou ,, and Zhizhi engineering, including laser welding (

Laser Welding) and Soldering Soldering, Soldering, Soldiers, Soldiers-Soldiers Specialist. When assembling the compacted fiber collimated state, in order to reduce the insertion loss (Insertion oss) of the quasi-mu / 9 1 device, the relative position of the fiber head 12 and the gradient index lens i 4 must be adjusted in real time, so that Output beam at working distance (working

Distance), to achieve the best parallel beam ’, namely the minimum beam divergence (Beam DiVergence) and the smallest deflection angle. However, the above-mentioned optical fiber collimator 1 with a graded index (GRIN) lens 14 or a manufacturing method thereof includes: July 11, 2002 Announcement No. 49425, "Optical fiber collimator and manufacturing method thereof Invention patent (application number

090128544), and published on January 2, 2001, 168, 31 9B1 "SYSTEM AND METHOD FOR ALIGNING OPTICAL FIBER COLLIMATORS" invention patent, etc., have the following disadvantages in the process and use: (1), the cylindrical gradient refraction Gradient-index (GRIN) lens itself has a high degree of difficulty in manufacturing technology, which cannot be easily molded, which increases the manufacturing cost relatively. (2) Once the length of each GRIN lens is selected, the working distance of the manufactured fiber collimator system is also fixed. Therefore, the working distance is determined first according to the needs of the functional components in manufacturing, and the length of the GRIN lens is determined. Because the required GRIN lens has various length specifications, it increases the trouble of the tube. (3) When assembling a GRIN-type fiber collimator, in order to reduce the insertion loss of the collimator (Insertion Loss), it usually needs to be adjusted immediately.

Page 6 561285 V. Description of the invention (3) The relative position of the optical fiber head and the graded-refractive index lens allows the output beam to achieve the best parallel beam within the working distance range, but each time the optical adjustment The calibration process involves X, Y, Z, 6 > and Φ five-axis degrees of freedom. The process of alignment and adjustment is quite complicated and relatively increases the production cost. (4) For functional parts with longer working distances, GRIN-type fiber collimators cannot maintain insertion loss (Insert Loss) below 0 · 15dB, resulting in reduced optical performance and are not suitable for long working distances. For components with a length of more than 100mm to 140mm, such as a light circulator (

Circulator), optical interleaver (Optical. Interleaver), optical switch (Optical Switch) and other multi-channel optical components (Multi-Port Optical Device), and the use quality can not meet the requirements. In addition, an aspherical lens has the same function as a GRIN lens, and can transform a point-emission light beam (such as an optical fiber end point) into a parallel light beam within an effective focal length f (Effective Focal, Length, EFL). Characteristics, but if an aspheric lens (Asphericai

Ler ^ s), to replace the CCD lens in the GRIN_type fiber collimator, it still meets the quite complicated optical & second adjustment operation, so until now, there is no type of optical fiber collimation roll, and the surface is transparent. See (Asphericai Lens) the invention; if it is for this purpose, the developer. The main method is Li Shao 2, which is to provide a lens for optical fiber collimator to form 4 =: a sleeve with a washer outside the washer and-aspherical surface of the washer through the machining process: and consider the jacket during the production process Length in the tube direction) Jin Zhong & i, and make the washer thickness gauge along the outer tube axis ..., at or greater than the effective focus of the aspheric lens

561285 V. Description of the invention (4) '--------, and the larger part is best not more than 30 # πι; then the nuclear aspheric lens and an optical fiber head are sleeved in the outer sleeve and fixed to the washer On both sides of the end, the defocus distance of the fiber end point (= di2f, = dl is the actual distance from the fiber end point to the aspheric lens) can fall within the range of 30-Ad-0, and thus cause all assembly The best fiber collimator completed—Working Distance (Working Distance) naturally falls within the range of 0 ~~ 140 mm, and then classified according to the working distance from qmm to η qmin, which can be viewed by users. It is easy to select according to the needs of use; the working distance of the optical fiber collimator made by this method and method can randomly cover various specifications between 0mm and 140mm, and keep the insertion loss below 0.15dB. Improve the optical performance, which can be applied to the components with long working distance to increase the application range, and no complicated optical adjustment process is required during the assembly process ^ 'It can greatly reduce the production cost. In order to make the present invention clearer and more detailed, the technical features of the present invention are described in detail below with reference to the following drawings: As shown in the second figure, it is the optical characteristics of an aspheric lens, where the aspheric lens 20 is the most Optimized, minimal aberration, aspherical lens with effective focal length f; when a Gaussian beam (Beam Waist = wl) exits from the fiber tip, the length dl (dl is the fiber end point to the aspheric • the distance of the surface lens) and the aspheric lens 20, focus on d2, and 2d2 is the optimal working distance of the fiber collimator system at this time, the waist width, that is, the spot radius change Is ω2, and single-mode fiber (single-mode fiber) is used to learn the relationship between ω2 and ω 1, f, Ad (Ad = d 1 -f) and its calculation formula. and

561285 V. Description of the invention (5) According to the above optical characteristics, 'When an aspheric lens is used instead of a GRIN lens for an optical fiber collimator, the relative distance between the fiber end point and the lens focal length f can be changed, that is, the optical fiber The end-of-focus distance Ad (△ (! = Dl-f), which is divided into △ (! = 0 when dl = f, △ (! ≫ 〇, dl > > when f) △ (! ≫ > 〇, and dl < f Ad < 〇 and other conditions, and analyze the various focusing conditions after passing through the lens, the optimal working distance of the fiber collimator system at this time is 2d2, The following results are obtained:

Case (1): When dl = f, △ (! = 0, the focal point is away from the lens f, the parallel light has the largest spot radius or spot size and the smallest scattering angle, the best work Distance is 2 f;

Case (2): When d 1 > f, Ad > 0, that is, the end point of the optical fiber moves away from the left in the figure, and the focus point gradually moves away from the lens f, that is, the optimal working distance becomes larger and larger, At this time, there is a gradually smaller spot size and a larger scattering angle;

Case (3): When dl > > f, Ad > 0, that is, the end point of the optical fiber moves to the left in the figure by more than a certain distance. At this time, the focus point is smaller than the lens f, and there is a small s ρ 〇tsize and a large scattering angle;

Case (4): When dl < f, △ (! ≪ 0, that is, the end point of the optical fiber is moved closer to the aspheric lens, the parallel light diverges without focusing, and its virtual focus point is in front of the aspheric lens 20 ( That is, d2 < 0), and there is no optimal working distance. According to the above, substituting the optical characteristics of single-mode fiber (single_mode fi ber), it can further be known that: when the defocus distance Ad ( Ad = dl-f) In the range of 5 ~ 60 // m, the optimal working distance reached by it can be from 0mm to 150mm, and the scattering angle is less than 0.025

561285 V. Description of the invention (6) The insertion loss of the collimator system comes from the misalignment (mi sal ignnient) of the Gaussian beams emitted by the two collimators and the unmatched spot-size. In the above Case (1) to Case (3), it can be assumed that the lens aperture size (Aperature) is much larger than the spot size of the incident Weiss beam, as long as the working distance of the two collimators is adjusted to the optimal working distance ', that is, 2d2, the collimator can approach zero due to the mismatched spot size insertion loss. In addition, the transverse direction misalignment and angular misalignment can be referred to the following papers: Shi fu Yuan and Nabeel A. Riza, General forinuls for oupling ~ l0ss charac ter i za ti onjo f single-mode fiber collimators by use of gradient-index rod lenses ”Applied Optics, ν〇1 · 38, ΝΟ · 15, ρ · 3214-3222 ·. As shown in the third, fourth and fifth figures, The present invention is designed based on the above-mentioned optical characteristics when an aspheric lens is used in an optical fiber collimator, and especially when the defocus distance (△ d) of the fiber end point can be effectively controlled, the optical fiber collimation can be controlled Working distance (2 d 2) of the condenser system. The manufacturing method of the optical fiber collimator of the present invention is mainly composed of an outer tube (Holder) 30 and an aspherical lens (Aspherical Lens) 40, and the outer tube There is a washer (Spacer) 31 in the inner diameter of 30. The manufacturing method includes the following steps: Provide an outer sleeve 30 with a washer 31 in the inner tube, and consider the machining tolerance to make the washer 31 The thickness T equal to or larger than the designed aspherical lens effective focal length f (Effective Focal Length, EFL), and wherein greater than a portion not exceeding the optimum 3〇; providing a

561285

The optical fiber 50 and its optical fiber head 51, the outer diameter of the optical fiber head 51 is the same as the inner diameter of the outer sleeve ，, and can be inserted into the outer sleeve 30 to abut the first end face 32 of the gasket 31 and be fixed; an aspheric lens is provided 40, its outer diameter design is the same as the inner diameter of the outer sleeve 30, can be sleeved within the outer sleeve 30 and abut the second end face 33 of the gasket 31 and be fixed, and its effective focal length f is detected by the wavelength of light; The optical fiber collimator that has been completed by the above steps, because the thickness of the gasket varies due to machining tolerances, the defocus distance of the fiber end point 52 (Ad = dl-f, dl is the fiber end point 52 to the aspheric surface) Lens distance) are controlled within the range of 30 // m ^ Ad ^ 0 ', and thus the optimal working distance of each fiber collimator is controlled within the range of 〇 ~~ & 〇_, so The optical fiber collimator can be set for each group, and its different working distance can be detected by optical instruments; the working distance can be divided into several levels from 0mm to u0mm (for example, every 20mm is a level), so that each fiber is collimated Filters are classified according to their respective working distances' and assigned to each Various components for different working distances can be easily selected at different levels. In addition, the aspherical lens 40 can be a molded aspheric glass lens with nearly zero aberration, that is, the aberration has passed through the aspheric high-order coefficient. After correction, it has approached zero (< 〇 · 〇25 Aat λ = 0. 6328 // m). The outer casing 30 may be a stainless steel outer casing (Stainless Steel Holder) or glass material, and the gasket 31 may be The outer sleeve 30 is made of a single body, and the thickness τ of the washer 31 is controlled to be equal to or greater than the effective focus length (EFL) f of the aspheric lens 40, and the larger part is not more than 3 0 // m. Best design principles, so consider mechanical processing;

Page 11 561285 V. Description of the invention (8) When the working error is about 5 ~ 15 // m, the thickness τ of the gasket M can be designed as T = (f + 15 // ηι) ± 15 / ζιη. The optical fiber head 51 and the aspherical lens 40 can be fixed to the first end surface 32 and the second end surface 33 on both sides of the gasket 31 with a mu glue, respectively. An air hole 34 of a proper size is provided in the length of the washer 31 to keep the internal air pressure the same as the outside 'so as to improve the reliability of environmental factors. Because the working distance of the optical fiber collimator system of the present invention can be effectively controlled by the thickness τ of the gasket, the required specification distance can cover a large range from 0111111 to 140 mm, and the insertion loss can be maintained at 0. · 1 & db or less; and the present invention does not require an optical calibration procedure in the actual assembly process, and only needs to use the rear section to detect the beam quality (Optical Beam Profile), the classification and screening of different working distances due to machining tolerances; therefore The invention can greatly reduce the production cost, avoid the time-consuming and laborious optical adjustment of conventional techniques, and improve the optical performance, and can be applied to components with long working distances, such as optical circulators and optical interleavers.

Multi-port optical devices such as Interleaver) and optical switching n. Therefore, the present invention has at least the following advantages: (1) The present invention can eliminate the need for tedious light alignment procedures during assembly. Considering the machining errors, the optimal working distance is slightly changed. The present invention only needs to be used in passive assembly (Passive After the alignment process is completed, the optical performance of the pair 2 is tested, including insertion loss, reflection loss, and optimal working distance. (2) In order to achieve the best optical characteristics at different working distances

561285 Shooting angle, etc., the spherical aberration of the optical fiber in the school, and the production of loss. Using the working distance from the disclosure of the present invention, the undisclosed drawing of the invention is the following. The technology of the smallest deflection angle lens, the relative position of the lens. . The change of the distance between the head and the aspherical lens, instead of not requiring an instant adjustment method, "indeed. And the present invention is applied to the novel and progressive embodiment of the invention and the person skilled in the art has equivalently changed or repaired it. V. Description of the invention (9) 'Including the smallest divergence and the lowest reflected light usually need to be adjusted immediately and the present invention uses a non-relative position error which cannot be compensated for the insertion (3), the hair, which can be produced in different summary Can take measures that have not been seen in the publication before the above-mentioned requirements. However, the above is not limited to a qualified scholar, and the hair accessories on which it is based should all cover the lowest insertion loss. The conventional use of a graded refractive head and a graded refractive index glass lens is used, because the optical fiber is the best work. Distance increased. Machining characteristics, off-collimator. "The manufacturing method of the optical fiber collimator achieves the stated effect. It has been in accordance with the specifications and descriptions, and is only for this example. Anyone who is familiar with the scope of the patent and applied for the scope of the patent application

Page 13 561285

The diagram is briefly explained. The first picture is a sectional view of a conventional fiber collimator. The second figure is a schematic diagram of the optical characteristics of an aspheric lens. The third figure is a flowchart of the manufacturing method of the present invention. FIG. 4 is an exploded sectional view of an optical fiber collimator made by the present invention. Fig. 5 is a sectional view of an optical fiber collimator made in the present invention. Brief description of part number 10 Fiber collimator 11 Glass tube 12 Fiber head 13 Optical fiber 14 Gradient index lens 15 Stainless steel tube 20 Aspheric lens 30 Outer tube 31 Washer 32 First end 33 Second end 3 3 Vent hole 4 0 Aspheric lens 50 fiber 51 fiber head 52 fiber end

Page 14

Claims (1)

The scope of the six patent applications, an ancient and earthy method of optical fiber collimator, the main method of the optical fiber collimator 3 4 丨 with-outer tube and-aspherical lens constituted by a sharp tube diameter t-塾 ring, its production method includes ΐ =; within the official processing tolerances' to make the thickness of the washer ^ EFL) ^ the most 隹; Deng points greater than eight in the tube is not more than 30 / zm = 2 and; ; ϋ: 套; =: Diameter design and ㈣ end face and fixed "inside and against the washer-, provided-aspherical lens, its outer diameter design and outer diameter of the outer sleeve ㈣ a can be sleeved into the outer sleeve and against the washer The second end surface is measured: the effective focal length f of the aspheric lens can be set by the optical wavelength and the fiber collimator that has been completed by the above steps. Because the gasket: j is different due to machining tolerances, the fiber end The defocus distance of the point is within the range, and therefore the optimal working distance of each optical fiber is controlled within the range of Omm ~ 140mm. ^ The optical fiber collimator set for each group is detected by optical instruments. Working distance; working distance from 0mm ~ 1 40mm A plurality of levels, each light by the collimator = working distance for each of the screening grade, and a home into different levels, the various elements for different working distance of the simple choice of Page 561 285 2. The manufacturer of the fiber collimator described in item 1 of the scope of the patent application, wherein the aspheric lens can be a molding aspheric glass lens (Molding Asphericai Glass Lens) with almost zero aberration. > 3. The manufacturer of the fiber collimator described in item 1 of the scope of the patent application, wherein the outer sleeve can be a stainless steel outer sleeve. 4. Fabrication of the optical fiber collimator as described in item 1 of the scope of the patent application, wherein the gasket can be formed integrally with the outer sleeve. 5. The optical fiber collimator described in item 1 of the scope of the patent application, wherein the outer sleeve can be a broken glass outer sleeve. / 6. The production of the optical fiber collimator described in item 1 of the scope of the patent application, in which the machining error of the tested s is in the range of 5 ~ 15 # m, and the loop length T can be designed as T = (f + 15 / im) ± 15㈣. 7. The production of the fiber collimator as described in item 范围 of the scope of the patent application, in which the fiber head and the aspheric lens can be fixed on the first end surface and the second creep surface of the two sides with UV glue, respectively. 8. Fabrication of the optical fiber collimator as described in item 1 of the scope of the patent application: where the length of the gasket: is provided with a vent hole for keeping the internal air pressure the same as the outside, thereby improving the reliability of environmental factors. 9. According to the manufacturer of the optical fiber collimator described in item 1 of the scope of the patent application, wherein the working distance of the optical fiber collimator is in the range of 0 mm to 14 mm, and it can be a level every 20 mm.