CN112327414B

CN112327414B - Automatic calibration device for miniature optical fiber collimator

Info

Publication number: CN112327414B
Application number: CN202011048883.5A
Authority: CN
Inventors: 赵京
Original assignee: Guangxi Anjiexun Electronic Science & Technology Co ltd
Current assignee: Guangxi Anjiexun Electronic Science & Technology Co ltd
Priority date: 2020-09-29
Filing date: 2020-09-29
Publication date: 2022-08-30
Anticipated expiration: 2040-09-29
Also published as: CN112327414A

Abstract

The invention discloses an automatic calibration device of a miniature optical fiber collimator, which comprises a silicon substrate with a first and a second opposite sides, wherein an optical fiber alignment area is arranged on the silicon substrate, a first optical fiber and a second optical fiber are inserted into the optical fiber alignment area from two corresponding side surfaces, and the two side surfaces are a first side surface and a second side surface; a driving region fabricated on the silicon substrate and adjacent to the optical fiber alignment region; and a plunger in the drive region contacting the first optical fiber through a gap in the drive region, wherein movement of the plunger displaces the first optical fiber relative to the second optical fiber. The silicon-based micromachined grooves with self-aligned springs of the present invention can be used to directly couple two or more optical fibers. This structure has a good platform that enables one to fabricate fiber optic devices without the use of lenses and coatings, thereby achieving broadband operation, low insertion, and significant cost reduction. The direct alignment method of the present invention broadens the application of many new direct alignment fiber devices.

Description

Automatic calibration device for miniature optical fiber collimator

Technical Field

The invention relates to a self-aligning optical fiber device, which comprises an optical switch, an optical attenuator, an optical tapping monitor, an optical tunable filter and the like, in particular to an automatic calibration device of a micro optical fiber collimator.

Background

Optical fiber is one of the most commonly used transmission media in optoelectronic systems for communication. Due to the small core diameter of optical fibers, active tunable alignment is commonly used in coupling to optoelectronic devices. Many fiber optic devices, such as switches, attenuators, tunable filters, and optical tap monitors, require coupling between two or more optical fibers so that optical signals can propagate between them or through an optical management component located in the gap between them. Currently, this coupling is achieved primarily by using collimators to expand the beam to achieve reduced angular sensitivity and to extend the transmission distance, and then adjusting the alignment between two or more fiber collimators to achieve low optical loss across the gap. Each collimator needs to consist of a polished fiber end of anti-reflection coating and an optical lens. The manufacturing process of the collimator is complex, including polishing, coating, lens manufacturing, and optical alignment. Fiber optic device assembly using fiber collimators also requires active precision alignment by skilled operators.

For many years, efforts have been made to reduce the complexity and cost of fiber-to-fiber coupling by means of non-tunable direct alignment. When the two fiber ends are perfectly aligned and the spacing is small, light entering one fiber passes through the two adjacent ends and continues to enter the second fiber with low loss. However, such fiber-to-fiber direct coupling requires high precision alignment and microstructures can be achieved. The most common method is to use a V-shaped microstructure to align the fibers. In this method, a round fiber is placed in a precisely manufactured V-groove. The V-shaped geometry ensures that two fibers placed in the same V-groove from opposite sides are naturally aligned with each other when the two fibers meet at the junction. The passive direct alignment from optical fiber to optical fiber eliminates the commonly used coupling coating, lens and adjustable alignment, and greatly saves the cost. However, the optical fiber is very sensitive to perturbations, such as epoxy fillers, due to the lack of a strong mechanical hold in place of the fiber within the shallow V-groove. The use of V-grooves is limited.

Another approach is to use a micro-groove with a spring on one side to automatically align the fiber by the spring pushing the fiber into alignment against the wall. An example of such a structure 10 is shown in fig. 1A, and is comprised of straight walls 14 of a spring plate retention channel 20. When the optical fiber 16 is inserted into the groove 20, the spring 12 urges the optical fiber 16 into contact with the wall 14, as shown in FIG. 1B. The cover slip is placed on top of the device which pushes the fiber 16 down into contact with the bottom of the trench. Thus, the optical fiber 16 is automatically aligned in the groove 20 from all four aspects.

This design is more robust than the V-groove design, and therefore highly repeatable, since the grooves 20 are deep enough to maintain the positioning of the optical fibers 16 in four ways. However, previous applications of trenches to switches have been limited to the use of mirrors with electrostatic actuation. This approach has several disadvantages, as the gap between the coupled fibers is larger due to the need to insert mirrors, thereby increasing losses. Bare fiber coupling requires extremely precise mirrors, increasing cost while reducing throughput.

Disclosure of Invention

The invention aims to solve the technical problem of an automatic calibration device of a miniature optical fiber collimator, which can effectively overcome the defects in the prior art.

The invention is realized by the following technical scheme: an automatic calibration device of a miniature optical fiber collimator comprises a silicon substrate with a first and a second opposite sides, an optical fiber alignment area is arranged on the silicon substrate, a first optical fiber and a second optical fiber are inserted into the optical fiber alignment area from two corresponding side surfaces, and the two side surfaces are a first side surface and a second side surface;

a driving region fabricated on the silicon substrate and adjacent to the optical fiber alignment region; and a plunger in the drive region contacting the first optical fiber through a gap in the drive region, wherein movement of the plunger displaces the first optical fiber relative to the second optical fiber.

As a preferred technical solution, the optical device is prepared from a silicon wafer.

Preferably, the silicon wafer includes a silicon on insulator wafer.

As a preferred technical solution, the optical fiber alignment region includes: a first optical fiber trench etched into the base and extending across the width of the base bottom, the trench having an open, flat trench bottom, a first alignment wall flat side, the first trench further having first and second trench regions having respective first and second side open outer ends of said base, said first and second optical fibers being insertable through the respective sides;

the first channel region having a plurality of first spring tabs secured to the channel walls directed toward the first alignment wall; the second channel region having a plurality of second spring tabs secured to the channel walls directed toward the first alignment wall;

a cover plate configured to cover at least a portion of the first trench region;

wherein, when the first and second optical fibers are inserted into the fiber groove through the respective open ends, the first and second spring tabs push the first and second optical fibers from the sides into contact with the first alignment wall, and the cover plate pushes the first and second optical fibers from the top so that they contact the bottom of the groove and are fixed in one of the portions of the first groove region, so that the first and second optical fibers are aligned with each other;

the drive region includes: a frame having first and second sides corresponding to the first and second sides of the base; a plurality of cross-beam support frames supporting the plungers therein; and an actuator within the frame configured to vertically move the first optical fiber by moving the plurality of beams, thereby causing the first optical fiber to move vertically.

Preferably, the optical device comprises a fiber optic attenuator.

Preferably, the drive region comprises spaced, vertically stacked, small displacement microfabricated spring actuators assembled in series within the frame;

each actuator comprises at least one of a plurality of cross beams; the first spring actuator includes a first plunger; a second spring actuator comprising a second plunger connected to the first spring actuator;

wherein: a displacement of the second spring actuator is transmitted by the first parameter through the second plunger at a second parameter less than the first parameter, and to the first plunger at a third parameter less than the second parameter; and the first plunger moves the first fiber by an amount of a third parameter to the second fiber.

As a preferred technical solution, the driving area is composed of a plurality of beams: a second cross member of length E + F, a second outer end connected to the second side of the frame and connected to the inner end of the first ram;

a third cross member having a third outer end connected to the second side of the frame; a second plunger located at a distance C from the second outer end, extending from the third beam to a second beam at a distance F from the first plunger; a fourth cross member having a first end connected to the first side of the frame;

a third beam positioned a distance A from the first side of the frame and extending from the fourth beam to a second plunger distance D from the third beam;

and a rod connected to the fourth beam a distance B from the third plunger a;

wherein the first displacement of the rod is transmitted through the fourth, third, second and first beams such that the displacement of the first plunger moved by the second displacement is less than the first displacement.

As a preferred solution, the total displacement reduction from the first displacement to the second displacement is equal to A/B × C/D × E/F.

Preferably, each beam is connected to a respective side of the frame by a flexible section which is thinner than the beam.

Preferably, the optical device comprises a fiber switch.

Preferably, the second portion of the first fiber groove guide includes a third portion wider than the first portion, the third portion being close to the gap in the driving region, and in which the spring piece does not protrude from the wall surface opposite to the first alignment wall;

and the fiber alignment region further comprises a second fiber groove guide etched in the base, having an open face, a second planar alignment wall, and a second bottom face; a third plurality of leaf springs extending from a wall of the second channel rail opposite the second alignment wall; a third open outer end at the second side of the base through which a third optical fiber can be inserted, the third open outer end being spaced from the second open outer end of the first fiber channel guide in the second portion;

and an internal opening connecting the second fiber groove guide and the third portion of the first fiber groove guide; wherein when a third optical fiber is inserted through the third open outer end, facing the second portion of the first fiber groove guide, and the cover plate is secured to the first groove, the third multi-spring plate urges the third optical fiber to contact the second alignment wall and the cover plate urges the third optical fiber to contact the second bottom surface;

when the first plunger is moved, the first optical fiber is correspondingly moved from a first position aligned with the second optical fiber to a second position aligned with the third optical fiber, thereby performing optical switching.

As a preferred solution, the plurality of beams in the driving area includes: a first cross member having an outer end connected to the first side of the frame and an inner end connected to the first side of the first ram; a second cross member having an outer end connected to the second side of the frame and an inner end connected to the second side of the first plunger; thus, when the actuator moves vertically, the first plunger is offset vertically relative to the first and second beams.

Preferably, the plurality of cross members further comprises a third cross member spaced from and parallel to the first cross member, the third cross member being connected to an outer end of the first side of the frame and to an inner end of the first side of the first plunger, the outer end of the first cross member being lower than the inner end of the first cross member, the outer end of the third cross member being lower than the inner end of the third cross member; the outer end of the second beam is lower than the inner end of the second beam, and the second beam contains a plurality of springs and is shaped as a bent tube.

Preferably, the first plurality of spring tabs extend from a wall of the first channel rail opposite the alignment wall at an upward angle away from the open outer end of the first portion; and the second plurality of spring tabs extend from a wall of the first channel rail opposite the alignment wall at an upward angle away from the open outer end of the second portion.

The invention has the beneficial effects that: the invention has high universality and low cost, and can produce various types of optical fiber devices without generating consumption phenomena such as insertion loss, extinction ratio and the like;

the fiber optic device type is fully automatically assembled by machinery for low volume production cost, the structure and method enable next generation high bandwidth communications upgrades;

an economical optical device platform and method based on fiber-to-fiber coupling without the use of lenses or coatings is also provided, and further, the device can be produced on a self-aligned device based miniature silicon substrate platform without the need for expensive active optical alignment. The structure and method efficiently produce optical devices without compromising optical performance, including return loss and optical power handling.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1A is a schematic diagram of a grooved fiber aligner with side springs and top cover member assembled;

FIG. 1B is a schematic illustration of the aligned fibers of FIG. 1A in a prior art configuration;

FIG. 2A is a schematic diagram of an embodiment of a manually variable optical attenuator, in accordance with the principles of the present invention;

FIG. 2B is another schematic diagram of the embodiment of FIG. 2A identifying distances;

FIG. 3 is a schematic diagram of an embodiment of a mechanical fiber switch according to the principles of the present invention;

figure 4 is a schematic diagram of an embodiment of a mechanical fiber tunable filter according to the principles of the present invention.

Detailed Description

All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.

Any feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

In the description of the present invention, it is to be understood that the terms "one end", "the other end", "outside", "upper", "inside", "horizontal", "coaxial", "central", "end", "length", "outer end", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the present invention.

Further, in the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

The use of terms such as "upper," "above," "lower," "below," and the like in describing relative spatial positions herein is for the purpose of facilitating description to describe one element or feature's relationship to another element or feature as illustrated in the figures. The spatially relative positional terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly

In the present invention, unless otherwise explicitly specified or limited, the terms "disposed," "sleeved," "connected," "penetrating," "plugged," and the like are to be construed broadly, e.g., as a fixed connection, a detachable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

A first embodiment of the present invention is a fiber optic attenuator 200, as shown in FIG. 2A. The device 200 is mounted on a silicon base 202, the silicon base 202 including a fiber alignment region 210 and an adjacent drive region 240. The microstructures of both

regions

210, 240 use a silicon wafer, preferably a sandwich silicon-on-insulator (SOI) wafer using standard semiconductor wafer fabrication processes. The fiber alignment region 210 contains a fiber groove guide (also referred to herein as a "groove") 212 that is etched into the silicon base 202 having

open ends

212A, 212B. The groove 212 has a straight flat ridge 204 opposite the front open area and a side upper wall 214A aligned. A plurality of springs 216 and 216' (only one spring of each set is identified in the figure) extend from the opposite lower wall 214B of the channel 212. Alignment wall 214A includes gap 206. Each spring 216, 216' is a thin silicon beam that is fixed at one end to wall 214B and unattached at the other end and extends into trench 212. The spring packs 216, 216' may extend into the grooves at any angle, including vertically. Preferably, however, the spring packs 216, 216 'are angled upwardly from the open ends 212A, 212B of the channel 212, respectively, to insert optical fibers (also referred to herein as "fibers") 218, 218' medially from both the left and right sides of the base 202. When fibers 218 and 218 'are inserted from

open ends

212A, 212B of channel guide 212, springs 216 and 216', respectively, urge fibers 218, 218 'toward alignment wall 214A such that fibers 218, 218' contact wall 214A, thereby aligning each other along wall 214A. The inner ends of the fibers 218, 218' are preferably angled where they meet to avoid the reflected light propagating back into the core. Preferably, the angle is less than about 12 degrees.

The fiber attenuator 200 may also include a cover plate 217 (shown in transparent outline) that pushes the fibers 218, 218' into contact with the trench floor 204. The cover 217 may be secured to the base 202 with epoxy or other material, for example, at the four corners or elsewhere, as represented by the four circles 224. The front-to-back depth of the groove 212 is preferably made slightly smaller than the diameter of the optical fibers 218, 218 'so that the cap 217 can contact the optical fibers 218, 218' and apply downward pressure against them away from the 204. Thus, the optical fibers 218, 218' are aligned and retained in all three dimensions by this passive trench guiding method.

The drive region 240 contains a series of spring actuators made of single crystal silicon. First actuator 240A includes a plunger 242 having one end in intimate contact with an inner end 218A of one of optical fibers 218 through gap 206 in wall 214A. The other end is connected to the inner ends of two silicon beams 244, 244 ', thereby connecting the two silicon beams 244, 244'. The outer ends of the cross beams 244, 244 'are connected to

opposite sides

241A, 241B, respectively, of an immovable frame 241 having flexible

thin sections

244A, 244A' (for convenience, the left and right sides of the frame 241 may be referred to herein as "frame 241A" and "frame 241B", respectively). Preferably, the cross members 244, 244' are angled upwardly at a small angle from the plunger 242 to the frame sides 241A, 241B in a shallow V-shape.

The second actuator 240B is within a frame 241 above the first actuator 240A and consists of a second plunger member 246 located adjacent the frame 241B. The lower end of the plunger member 246 is in close contact with the lower cross member 244'; the upper end is connected to a third silicon beam 248, and one end of the third silicon beam 248 is connected to the frame 241B by a thin flexible section 248A. The third silicon beam 248 is preferably angled upward from its connection with the frame 241B to the oppositely facing frame 241A.

A third actuator 240C is mounted in the frame 241 above the second actuator 240B and includes a third plunger member 250 positioned adjacent the frame 241A and having a lower end in intimate contact with the lower beam 248 and an opposite end connected to a fourth silicon beam 252. One end of the fourth silicon beam 252 is connected to the frame 241A by a flexible section 252A, and independently extends toward the frame 241B by the other end. The fourth silicon beam 252 is approximately horizontal.

The device may also include a fill liquid having an optical index matching the optical fibers 218, 218' to fill the gaps between the optical fibers. The insertion loss is reduced by bridging the propagation of light by reducing its divergence angle and path length. It also increases return loss, which is a desirable choice for many applications.

Referring to FIG. 2B, in operation, the upper fourth beam 252 is pushed downward by a rod 254, such as by manually or electrically turning a screw 256 with fine threads. The beam 252 bends downward near the flexible section 252A of the frame 241A, pushing the plunger 250 downward, which in turn bends the beam 248 downward. The displacement of the plunger 250 is a/B times less than the displacement of the screw 256, where B is the distance from the plunger 250 to the screw 256 and a is the distance from the plunger 250 to the frame 241A. By contacting displacement beam 248, plunger 246 moves downward, thereby flexing beam 244' downward. Further, the displacement of the plunger 246 is C/D times greater than the displacement of the plunger 250, where D is the distance from the plunger 250 contact point to the plunger 246 and C is the distance from the plunger 246 to the frame 241B. Since the plunger 246 is in contact with the beam 244, the movement of the beam 244' also moves the first plunger 242 downward, with a reduction factor of E/F, where F is the distance from the plunger 246 contact point to the plunger 242 and E is the distance from the plunger 246 center to the frame 241B. Thus, the plunger 242 pushes the fiber 218 downward against the bias of the spring 216, resulting in a misalignment between the fibers 218 and 218'. The total displacement reduction of the device of the invention thus produced is A/B × C/D × E/F. Therefore, the function of manually, accurately and controllably attenuating the strength of the optical fiber is realized.

Manually controlled optical attenuation is difficult due to the small size of the optical fiber core, which is only a few microns. 2A, 2B described herein provide a shift reducer that improves control accuracy. The structure 200 is shown. In addition to the three described and illustrated herein, the drive displacement may be reduced by cascading several displacement reducers to further improve control accuracy. In addition, all of the displacement reducers, actuators, and moving fibers are designed to achieve up and down motion of 256 using the mechanical properties of the natural elasticity of the single crystal silicon beam, which is a necessary characteristic of the variable optical attenuator. The invention realizes all important characteristics of the silicon plane optical fiber attenuator, improves the performance and reduces the manufacturing cost. Conventional manual fiber attenuators made with discrete optical components have optical insertion losses of about 0.6db, whereas devices of the present invention optimally can achieve significantly lower losses of about 0.1db, and with manufacturing costs reduced by a factor of about 5 or more.

A second embodiment, according to the present invention, is a fiber optic switch 300, as shown in fig. 3. 300 are fabricated on a silicon substrate 302, the silicon substrate 302 including a fiber alignment region 310 and an adjacent drive region 340, both of which are microstructures made using silicon wafers (preferably, mezzanine SOI wafers are fabricated using standard semiconductor wafers). In the fiber alignment region 310, the optical fiber 300 includes a first fiber groove guide groove 312, the first fiber groove guide groove 312 being embedded in a silicon substrate 302 having

open ends

312A, 312B. An upper alignment wall 314, which is straight and flat on one side of the channel 312, and a plurality of steel springs 316 and 316 extending from the side of the channel 312 opposite the alignment wall 314. A gap 306 is formed through the alignment wall 314. As shown in FIG. 3, the gap 306 is approximately three-quarters of the distance from the left side to the right side of the base 302, and the gap 306 may be formed elsewhere along the alignment wall 314. Each

spring

316, 316', 318 is a thin silicon beam extending from the side of the trench 312 opposite the alignment wall 314, with the unattached other end extending into the trench 312. The springs 316, 316' may extend into the grooves at any angle, including vertically. However, the

springs

316, 316', 318 are angled upward from the left and right sides of the base 302, respectively, away from the open ends 312A, 312B of the channel 312, toward the gap 306. When a pair of optical fibers 320 and 320 ' are inserted from the left and right ends 312A, 312B, respectively, of the channel guide 312, the

springs

316, 316 ', 318 urge the optical fibers 320 and 320 ' toward the alignment wall 314, bringing them into contact with the wall 314, thereby aligning one another along the wall 314.

The switch 300 also includes a second fiber groove guide 326, the second straight fiber groove guide 326 etching an outer open end 326A below one end 312B of the first groove 312, sloping upward toward the alignment wall 314, and including an inner open end 326B into the first groove 312. The second channel 326 includes a straight flat alignment wall 322 on one side and a multi-steel spring 324 on the side of the second channel 326 opposite the alignment wall 322. In the figure, the alignment wall 322 is a lower wall of the second groove 326; however, the 300 may be assembled with the alignment wall 324 on the upper wall of the second groove 324.

Each leaf spring 324 in the second channel 326 is a thin piece of silicon with one end attached to the channel wall opposite the alignment wall 322 and the other end unattached from the opening of the channel 326A in the direction 326A, extending up into the channel 326A. When the fiber 328 is inserted from the right end 326A of the groove guide 326, the spring 324 pushes the fiber 328 toward the alignment wall 322, causing it to engage the alignment wall 322.

The first groove guide 312 includes three regions. The first region 312' may be slightly wider than the fiber 320. Second, the middle region 312 "is much wider than the first region 312'. The third region 312 "is wider than the first region 312 'and narrower than the second region 312'. The wall of the third region 312' opposite the alignment wall 314 slopes downwardly from left to right such that it is aligned with the wall 322 of the second trench 326, forming a continuous surface. The

springs

316 and 318 extend only to the first and second regions 312 'and 312 ", and the third region 312' is empty.

Trenches

312, 326 are etched into the pedestal 302, with the plate bottom surface 304 opposite the front openings of the

trenches

312, 326. The depth of the

grooves

312, 326 is slightly less than the diameter of the

optical fibers

320, 320' and 328. A cover plate 330 is placed over the fiber alignment region 310 and urged toward the floor 304 so that the

fibers

320, 320', 328 are positioned in the

grooves

312, 326, in tight connection with the respective alignment walls and floor.

In the drive region 340, a spring plunger 342 is mounted on the frame 341 and connected to a plurality of

springs

346A, 346B, 346C. Spring beams 346A, 346B, 346C are made of a single crystal silicon plate, two 346A, 346B being spaced apart and parallel, with their inner ends connected to one side (left side in the figure) of actuator 342 and the inner end of third beam 346C connected to the other side (right side in the figure) of plunger 342. The outer ends of the two

beams

346A, 346B are connected to one side 341A (left side in the drawing) of the frame 341, and the outer end of the third beam 346C is connected to the other side 341B (left side in the drawing) of the frame 341. In the embodiment shown in the figures, the outer end of each beam is lower than the inner end. As shown in the embodiment of fig. 3, the third beam includes a number of spring bends.

In operation, the plunger 342 is pushed downward by the actuator contact 344, through the gap 306, pushing the optical fiber 320 downward against the bias of the spring 318, and through the third region 312' of the second groove 312 to contact the second alignment wall 322. The optical fiber 320 moves from being aligned with the optical fiber 320' to being aligned with the optical fiber 328. The angle at which the fiber 320 is pushed downward corresponds to the angle of the second alignment wall 322. Thus, the optical fiber switching function is realized.

An electromagnetic relay may be used to push the micro-plunger 342 through the actuator contact 344. Thus, an electrically controllable optical fiber 1x2 switch is achieved without complex optical alignment. The invention realizes low cost and high yield production through full automation of the manufacturing process. It should be appreciated that the alignment region 310 may be configured to switch 320 between more than two fibers 320 'and 328 by a wider third region 312' and increasing the groove at a steeper and steeper angle. Precise discrete displacement of the actuator 320 to a particular position corresponding to the additional guide slot should be defined.

A third embodiment of the present invention is a fiber tunable filter 400, as shown in fig. 4. The device 400 is fabricated on a silicon substrate 402 and includes a fiber alignment region 410 and upper and

lower drive regions

440A, 440B (collectively 440) on opposite sides (upper and lower in the figure) of the fiber alignment region 410. The fiber alignment and drive regions 410, 440 have microstructures fabricated using silicon wafers, preferably using a sandwich SOI wafer using standard semiconductor wafer fabrication processes employing photolithography and etching. In fiber alignment region 410, apparatus 400 includes a straight fiber groove guide 412 etched in silicon base 402, having a flat bottom surface 404, a straight flat alignment wall 414 on one side, and multiple leaves 416 and 416' on the side of groove 412 opposite alignment wall 414. The depth of the groove 412 is slightly less than the diameter of the fiber. Each spring 416, 416' comprises a thin silicon beam secured at one end to the alignment wall 414; the unattached end extends at an angle into the channel 412. The springs 416 and 416' are angled upward and away from the ends of the channel 412.

When a pair of optical fibers 418 and 418 ' are inserted from the left and right ends of the channel guide 412, respectively, the springs 416 and 416 ' urge the optical fibers 418, 418 ' toward the alignment wall 414 so that they contact the wall 414 and are aligned with each other along the wall 414. The inner ends of the two optical fibers 416 and 416' are coated with an optically highly reflective layer and have a gap 420 so that light is reflected back and forth between the two coated fiber ends to form an optically resonant etalon. The cover 422 is placed over the fiber alignment region and pushed toward the rear 404 so that the fibers 416 and 416' are positioned in the groove 412, connecting the bottom 404 surface of the groove 412 and the alignment wall 414. The optical fibers 416 and 416 'are secured to the base 402 near the two outer ends 424 and 424' of the channel 412 using epoxy so that the two fiber ends at the central gap 420 are free to move. The cover 422 is also secured to the base 402 by pressurized epoxy, for example, at its four corners, while the cross-section of the fiber-to-fiber gap region 420 is free of epoxy so that the two fiber ends near the central gap 420 are free to move.

The

drive regions

440A, 440B shown in fig. 4 each include a left portion and a right portion separated by a central portion, although other configurations may be used. Both the left and right side portions include several vertically spaced horizontal conductive silicon beams 442 and 442 '(respectively in the upper region 440A) and 442 ", 442'" (respectively on the left and right sides in the lower region 440B) to form thermal actuators.

In operation, an electrical current is applied to the pair of electrodes 444 and 444'. When current is passed through the plurality of conductive

thin silicon beams

442, 442 ', 442 ", 442'", the beams 442, 442 ', 442', 442 '"heat up and spread laterally outward from the central portion of the 400, as indicated by arrows a, a'. Thus, the gap 420 between the fibers 416, 416' increases, resulting in a change in the location of the etalon resonance peak. As the current decreases, the gap 420 also decreases and the optical resonance peak changes accordingly. Thus, fiber tunable filters are realized without the use of complex active optical alignment. The invention realizes low cost and high yield under the condition of automation of the production and manufacturing process.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that are not thought of through the inventive work should be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope defined by the claims.

Claims

1. The utility model provides a miniature optical collimator automatic calibration device which characterized in that: a silica-based substrate including first and second opposite sides, an optical fiber alignment region disposed on the silica-based substrate, first and second optical fibers inserted into the optical fiber alignment region from corresponding two side surfaces, the two side surfaces being first and second side surfaces;

a driving region fabricated on the silicon substrate and adjacent to the optical fiber alignment region; and a plunger in the drive region contacting the first optical fiber through a gap in the drive region, wherein movement of the plunger displaces the first optical fiber relative to the second optical fiber;

the optical fiber alignment region includes: a first optical fiber trench etched into the base and extending across the width of the base bottom, the trench having an open, flat trench bottom, a first alignment wall flat side, the first trench further having first and second trench regions having respective first and second side open outer ends of said base, said first and second optical fibers being insertable through the respective sides;

wherein, when the first and second optical fibers are inserted into the fiber groove through the respective open ends, the first and second spring pieces push the first and second optical fibers from the sides into contact with the first alignment wall, and the cover plate pushes the first and second optical fibers from the top so that they contact the bottom of the groove and are fixed in a portion of the first groove region, so that the first and second optical fibers are aligned with each other;

the drive region includes: a frame having first and second sides corresponding to the first and second sides of the base; a plurality of cross-beam support frames supporting the plungers therein; and an actuator within the frame configured to vertically move the first optical fiber by moving the plurality of beams, thereby causing the first optical fiber to move vertically;

the drive region comprises spaced, vertically stacked, small displacement, microfabricated spring actuators assembled in series within the frame;

each actuator comprises at least one of a plurality of beams; the first spring actuator includes a first plunger; a second spring actuator comprising a second plunger connected to the first spring actuator;

wherein: a displacement of the second spring actuator is transmitted by a first parameter through the second plunger at a second parameter less than the first parameter, and to the first plunger at a third parameter less than the second parameter; and the first plunger moves the first fiber by an amount of a third parameter to the second fiber.

2. The automatic calibration device for miniature optical fiber collimator according to claim 1, wherein: the optical device is prepared from a silicon wafer.

3. The automatic calibration device for miniature optical fiber collimator according to claim 2, wherein: the silicon wafer comprises a silicon on insulator wafer.

4. The automatic calibration device for miniature optical fiber collimator according to claim 1, wherein: the drive zone is comprised of a plurality of beams: a second cross member of length E + F, a second outer end connected to the second side of the frame and connected to the inner end of the first ram;

a third cross member having a third outer end connected to the second side of the frame; a second plunger located a distance C from the second outer end extending from the third beam to a second beam at a distance F from the first plunger; a fourth cross member having a first end connected to the first side of the frame;

and a rod connected to the fourth beam a distance B from the third plunger a;

5. The automatic calibration device for miniature optical fiber collimator according to claim 4, wherein: the total displacement reduction from the first displacement to the second displacement is equal to A/B C/D E/F.

6. The automatic calibration device for miniature optical fiber collimator according to claim 4, wherein: wherein each beam is connected to a respective side of the frame by a flexible section that is thinner than the beams.

7. The automatic calibration device for miniature optical fiber collimator according to claim 1, wherein: the second portion of the first fiber groove guide includes a third portion that is wider than the first portion, the third portion being close to the gap in the driving region, and in which the spring tab does not protrude from a wall surface opposite the first alignment wall;

and the fiber alignment region further comprises a second fiber groove guide etched in the base, having an open face, a second planar alignment wall, and a second bottom face; a third plurality of leaf springs extending from a wall of the second channel rail opposite the second alignment wall; a third open outer end at the second side of the base through which a third optical fiber can be inserted, the third open outer end being spaced from the second open outer end of the first optical fiber groove guide in the second portion;

8. The automatic calibration device for miniature optical fiber collimator according to claim 7, wherein: the plurality of beams in the drive zone include: a first cross member having an outer end connected to the first side of the frame and an inner end connected to the first side of the first ram; a second cross member having an outer end connected to the second side of the frame and an inner end connected to the second side of the first plunger; thus, when the actuator moves vertically, the first plunger is offset vertically relative to the first and second beams.

9. The automatic calibration device for miniature optical fiber collimator according to claim 8, wherein: the plurality of cross-members further including a third cross-member spaced from and parallel to the first cross-member, the third cross-member being connected to an outer end of the first side of the frame and to an inner end of the first side of the first plunger, the outer end of the first cross-member being lower than the inner end of the first cross-member, the outer end of the third cross-member being lower than the inner end of the third cross-member; the outer end of the second beam is lower than the inner end of the second beam, and the second beam contains a plurality of springs and is shaped as a bent tube.