TW455716B - Optical fiber Mach-Zehnder interferometer employing miniature bends - Google Patents

Abstract

An optical fiber Mach Zehnder interferometer includes a first and second elongate optical fiber having a core and a cladding, first and second couplers wherein the cladding of the first optical fiber is coupled to the cladding of the second optical fiber. The first optical fiber includes a first elongate interfering arm where the first optical fiber extends between the first and second couplers. The first interfering arm includes a miniature bend formed therein. The second optical fiber includes a second elongate interfering arm extending between the first and second couplers and may also include a miniature bend formed therein. The miniature bends are contemplated to be either packed or unpackaged. The fibers may exhibit different coefficients of thermal expansion to maintain the path length differences of the interfering arms.

Description

Duo printed by employees of the Intellectual Property Bureau of the Ministry of Economic Affairs 4 5 5 7 1 5 A7 ------ B7 V. Description of the invention (1)% of invention invention This invention relates to fiber optic Mach-Zehnder interferometers, especially to Fiber optic Mach-Zehnder interferometer with miniature flexible waveguide on one or more interference arms. The conventional technique is to form a non-equivalent Mach-Zehnder interferometer with a facet combiner with two pairs of parallel linear optical fibers. Figure 1 depicts a conventional typical fiber optic Mach-Zehnder interferometer 10. The interferometer 10 includes first and second extension optical fibers 12 and 14 coupled to first and second optical couplers 22 and 24. Each of the optical fibers 12 and 14 has interference arms 16 and 18 extending between the couplers 22 and 24, respectively. The interference arms 16 and 18 are arranged in a conventional manner to have different optical lengths, so that one of the interference arms is longer than the other. Long 'to use optical fibers with different propagation constants or close to this combination ^ The unequal size of the optical path length of the phase-sensitive interference arms determines the wavelength sensitivity of the interferometer. The path lengths are almost equal. The light that enters the optical fiber 12 will couple with the optical fiber 14 at the coupler 22 and cause interference with the coupler 24, so all the light is generated from the optical fiber 12 to the coupler 24. If the phase sensitive regions 16 and 18 are non-equivalence, light will be generated from the optical fibers 12 and 14 to the coupler 24 in different proportions according to the unequal size of the light wavelength and the path length. In general, as the wavelength increases, the light shocks between the upper and lower fibers. The larger the path length unequal value, the smaller the value of the wavelength change, allowing light to be transferred from one fiber to another. However, it is not easy to manufacture fiber sections of virtually different lengths without loss. Moreover, as shown in Figure 1, the structure of the interferometer 10 has an optical fiber exposed in the opposite direction, so additional space is required to accommodate the subsequent paper in the packaging. The paper size applies to the Chinese national standard (CNS > A4 specification (210 X 297 mm). ) —Ii ---------- τ 'Pack 1 ---- Order --------- Line- (Please read the notes on the back before filling this page) A7 4557 16- -------- 5. Description of the invention (2) Bending radius at both ends of the fiber. However, the minimum radius of the fiber using a mini-flexible waveguide is also a well-known technology. As disclosed in US Patent No. 5,138,676 The transmission optical core of the optical fiber can be formed with a reduced diameter. The reduced core can be bent and heat-annealed to provide a curved waveguide for the optical fiber, and exhibit low energy loss. Miniature flexible waveguides can be formed below 0.5 mm Radius without high attenuation and low internal stress. For example, 'This technology allows 180-degree bending with low loss to form a package with a diameter of less than 2.0mm and a length of 8.0mm. This low-loss flexible waveguide can be formed in a single mode or Multimode fiber. The diameter is usually reduced by chemical Removal of some coated glass to thin the fiber to achieve 'or a combination of these technologies. For single-mode devices, the fiber is processed so that the basic mode of the original fiber adiabatically progresses to the basic mode of the improved fiber to avoid light loss The flexible waveguide can be housed in different packages so that no material is in contact with the fiber in the processing area. Therefore, a Mach-Zehnder interferometer incorporating a miniature flexible waveguide in the fiber optic component is needed to size the interferometer , Thermal sensitivity, and vibration sensitivity are minimized. Ί SUMMARY OF THE INVENTION 1 The present invention provides a fiber-optic Mach-Zehnder interferometer comprising first and second extension fibers with a core and a cover, and having first and second A coupler in which the coating of the first optical fiber is coupled to the coating of the second optical fiber. The Mach-Zehnder interferometer of the present invention further includes a first extension interference arm, which is formed by the first optical fiber extending from the first and second couplers. A second extended interference arm formed and including a second optical fiber extending between the first and second couplers. The first interference arm includes at least one miniature flexible waveguide formed in it. This paper size is applicable to the Chinese National Standard (CNS) A4 (210 X 297 mm) ----: ------- -------- Order --------- line, ί Please read the notes on the back before filling out this page} Printed clothing for employees' cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 455716 A7 H7 V. Invention Explanation (3) The second interference arm may also include a miniature flexible waveguide formed therein. In one embodiment of the present invention, the miniature flexible waveguide of the first interference arm is nested in the second interference arm. Furthermore, The Mach-Zehnder interferometer of the present invention can be combined with a packaged miniature flexible waveguide or an unpackaged miniature flexible waveguide. When an unpackaged micro-flexible waveguide is used, the interference arm can be fixed to a supporting substrate with adhesive epoxy resin or adhesive gel. The Mach-Zehnder interferometer of the present invention can also exhibit reduced thermal sensitivity by selecting fibers with different coefficients of thermal expansion to handle different total length changes caused by interference arms of different lengths due to temperature. [Brief description of the diagram] Fig. 1 shows the structure of a linear Mach-Zehnder interferometer. Fig. 2 shows a block diagram of a Mach-Zehnder interferometer using a miniature flexible waveguide on an interference arm of the present invention. Figure 3 shows the architecture of a Mach-Zehnder interferometer using a miniature flexible waveguide on one of the interference arms. Figure 4 shows the coupled output of a non-equivalent Mach-Zehnder interferometer with a 3mm optical length difference according to the present invention. "Figure 5 depicts the Mach-Zehner using a 90-degree miniature flexible waveguide in the interference arm of the present invention. Another example of a Del interferometer. Figure 6 depicts a Mach-Zehnder-interferometer using a pre-packaged miniature flexible waveguide of the present invention. Figure 7 depicts another embodiment of a Mach-Zehnder interferometer using a 90-degree pre-packaged miniature flexible waveguide on an interference arm of the present invention. 28 and 9 describe other embodiments of the Mach-Zehnder interferometer using an unpackaged miniature flexible waveguide of the present invention. CNS A4 Specification ⑵0 (Please read the precautions on the back before filling this page)

^ i I --.--- til ------ ^ I Printed by the Consumers' Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs X 297 mm) 455716 A7 B7 V. Description of the invention (4) Figure 10 depicts the interference of the invention Another embodiment of a Mach-Zehnder interferometer using a 90-degree pre-packaged miniature flexible waveguide on the arm. fExample 1 The present invention proposes a fiber-optic Mach-Zehnder interferometer, which can form a miniature flexible waveguide in a phase-sensitive area. The miniature flexible waveguide can be used to shorten the length of the interferometer, reduce the diameter of the interferometer, or design non-equivalence interferometers. The Mach-Zehnder interferometer of the present invention is the only one that allows the designer to adjust the physical layout of the fiber optic components to match the space constraints of the workplace ^ In addition, the polarity dependence of the interference arm of the interferometer can be determined by The entity adjusts the interferometer arms of the interferometer to equalize. FIG. 2 illustrates the optical fiber Mach-Zehnder interferometer u0 of the present invention. The interferometer 110 is composed of first and second extension fibers 112 and 114, and each extension fiber 112 and 114 has a core and an outer cover. The optical fibers 112 and 114 are connected to the couplers 116 and 118. The optical fiber 112 provides a first interference arm 120 extending between the couplers 116 and 118, and the optical fiber 114 provides a second interference arm 122 extending between the couplers 116 and 118. In addition, each of the interference arms 120 and 122 includes miniature flexible waveguides 124 and 126 located at the core and each having a curvature of about 180 degrees. The interference arm 120 and the miniature flexible waveguide 124 are ideally nested within the interference arm 122 and the miniature flexible waveguide 126. The so-called drum cover in the present invention refers to a range bounded by an interference arm and a combined miniature flexible waveguide by a second interference arm and a combined miniature flexible waveguide. The so-called nesting does not mean that a miniature flexible waveguide is located between the two ends of the second miniature flexible waveguide. Therefore, the present invention provides an interferometer that uses a miniature flexible waveguide on at least one interference arm to greatly reduce the diameter. In general, the optical fiber has a lower coating reflectance than the core, and the light can pass through the optical fiber under the condition of negligible loss. The paper size applies to the national standard (CNS) A4 specification (210 X 297 public love) (please first Read the notes on the back and fill in this page) Install '--------- Order ---------- Line · Printed by the Consumer Consumption Cooperative of Intellectual Property Bureau of the Ministry of Economy A7 455716 ____B7____ V. Invention Explanation (5). The light can be viewed as guided by the core / clad's overall internal reflection. With the micro-flexible waveguide technology, the diameter of the optical fiber is reduced in the curved area. A structure is designed in which light is mainly guided by the surrounding air as the cover, and the optical fiber in the reduced diameter area is used as the core. Because the reflection coefficient of the surrounding air is nearly equal, the effective core / covering coefficient difference in the bending area is about 0.46 compared to the 0.003 difference for correcting the optical fiber. As a result, light is more tightly confined to the bending area and can withstand smaller bending radii without the need to connect radial patterns. Although it has a relatively small 180-degree bend, the light loss of the miniature flexible waveguide is very small over the entire 1260 to 1650 nm spectral band. For example, the maximum loss on both sides of the spectral band is generally less than 0.2 dB. So 'the flexible waveguide can be used in telecommunication windows of 1300 and 1550 nm. And because the flexible waveguide is located on a plane, it is assumed to have a small birefringence, but the measured polarity dependence loss is less than 0.003dB. FIG. 3 illustrates another fiber Mach-Zehnder interferometer 210 according to the present invention. The interferometer 210 is composed of first and second extension fibers 212 and 214, and each extension fiber 212 and 214 has a core and an outer cover. The optical fibers 212 and 214 are connected by couplers 216 and 218. The optical fiber 212 provides a first interference arm 220 extending from the couplers 216, 218, and the optical fiber 214 provides a second interference arm 222 extending from the couplers 216, 218. In addition, the interference arm 220 includes first and second miniature flexible waveguides 224 and 228. Although other bending angles are clearly considered to align the two ends of the optical fibers 212 and 214, each of the miniature flexible waveguides 224 and 228 forms a bend of approximately 120 degrees. The interference arms 222 form a straight line. The interferometer 210 controls the wavelength response of the MZI by controlling the difference in optical length of the two interference arms. Figure 4 shows the spectral response 'calculated by the interferometer of the present invention, in which the optical length difference between the two interference arms is about 3 mm. This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) < Please read the notes on the back before filling this page)

Packing --------- Order · -------- I Printed by the Employees 'Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs Printed by the Employees' Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs Printed by 455716 V. Invention Description (6) Reference Fig. 5 'The non-equivalence Mach-Zehnder interferometer 410 can also form a new architecture with a 90-degree miniature flexible waveguide for applications where short devices need to be guided to each other at right angles. The interferometer 4 includes optical fibers 412 and 414 mounted on a right-angle substrate 416. Each optical fiber 412 and 414 includes an optical transmission core 418 and a concentric coating 42 (a first optical fiber 412 defines a first interference arm 423, and a second optical fiber 414 defines a second interference arm 425, and the first interference arm 423 and The second interference arm 425 extends between the first and second couplers 422 and 424. The interference arm 423 has a first 90-degree miniature flexible waveguide 430 between the couplers 422 and 424, and the interference arm 425 is also on the coupler There is a second 90-degree miniature flexible waveguide 432 between 422 and 424. The miniature flexible waveguide 430 is nested within the miniature flexible waveguide 432. In this case, the difference in the optical path length of the fiber is the use of the miniature flexible waveguide 430 and 432 are established with different bending radii. The present invention also considers that the optical fiber used to assemble the coupler does not need to be fused together like a polished block coupler. In addition, the coupler used in the present invention can be symmetrical Type or asymmetric type. The distribution ratio (spUtiing rati0) of the coupler of the present invention can be a value other than 50%. Moreover, the distribution ratio and the maximum distribution ratio of the coupler need not be the same, such as the distribution of an asymmetrical coupler The rate is 40%. The invented interference arm also does not need to be symmetrical. Therefore, this architecture can be used to make a wavelength distribution multiplexer with or without a fiber Bragg grating formed adjacent to the coupler. However, According to U.S. Application No. 09/421, Π3, the present invention also considers that the fiber Bragg grid can be formed adjacent to each coupler. The interferometer of the present invention can also be derived from one or more photosensitive optical fibers Assembly. Moreover, each coupler can be composed of more than two optical fibers. For example, a 1x3 coupler can be composed of one or more photosensitive fibers and other non-inductive. This paper is applicable to China National Standard (CNS) A4 (210 x 297 mm) Li) --------------- install -------- order --------- line_ (please read the precautions on the back before filling in this Page) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 455716 Λ7 -------- -B7 V. Description of the invention (7) Fiber assembly. The described interferometers 110 and 210 do not have a protective casing or installation However, the micro-flexible waveguide of the optical fiber can be accommodated in different packaging, and there is no packaging The fiber is in contact with the optical fiber in the traveling area. Referring to FIG. 6, the optical fiber Mach-Zehnder interferometer 510 of the present invention uses a pre-packaged miniature flexible waveguide. The interferometer 510 includes a first extension fiber 512 and a first extension fiber fixed on an extension substrate 516. Two extended optical fibers 514. Each optical fiber 512 and 514 also includes an optical transmission core 518 and a concentric coating 520. The first optical fiber 5 12 between the first and second couplers 522 and 524 is defined by the second optical fiber 514 The optical fiber 512 includes a first miniature flexible waveguide 530 extending between the couplers 522 and 524, and the optical fiber 514 also includes a second miniature flexible waveguide 532 extending between the couplers 522 and 524. Miniature flexible waveguides 532 and 534 can be packaged in advance, so that each waveguide forms a fixed pre-bent structure in the housings 536 and 538 for assembly to the substrate 516 and coupling the optical fiber between the couplers 522 and 524 . The optical fibers 512 and 514 are optically coupled to the first and second couplers 522 and 524, and are fixed by using a first epoxy-based resin tack 526 and a second epoxy-based resin tack 528 on the other side of the couplers 522 and 524.于 Substrate 516. The epoxy resin tack 528 is preferably not in contact with any part of the miniature flexible waveguide 530 or 532. First, the flexible waveguides 530 and 532 are manufactured and then packaged in individual protective cases 536 and 538. The housing 536 provides a pair of fiber guide portions 512a and 512b at opposite ends of the first optical fiber 512. Similarly, the housing 538 is provided with a pair of optical fiber guide portions 514a and 514b at opposite ends of the second optical fiber 514. After that, the coupled guides of the miniature flexible waveguide are combined to form the manufactured couplers 522 and 524. Therefore, the phase-sensitive area of the interferometer consists of the optical fiber extending between the couplers 522 and 524. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 public love) (Please read the precautions on the back before filling in this page)

Equipment .------ Order --- I --- I 4557 1 6 A7 B7__ 5. Defined by the invention description (8). In order to avoid contact with the substrate 516, the couplers 522 and 524 are preferably suspended at a position with a diameter of a fiber above the substrate 516, and the miniature flexible waveguides 530 and 532 are preferably suspended in the individual housings 536 and 538. The present invention also uses one of the packaged flexible waveguides to be located further from the coupler than the other packaged flexible waveguide to provide any required physical path length difference between the interference arms of the two interferometers. . In addition, when the packaged miniature flexible waveguide is located near the middle point of the phase-sensitive area, the length of the interferometer of the present invention is preferably cut to about half the length of the conventional interferometer 10. Furthermore, all of the optical fiber guide portions 512a, 512b, 514a, and 514b are exposed from one end of the interferometer ', so the other end does not need a guide portion and approaches the wall surface. In this architecture, a packaged miniature flexible waveguide is used. If a larger flexible waveguide is placed in the phase-sensitive area of the interferometer, the interferometer can be combined without requiring large side offset values. Referring to FIG. 7 ', a non-equivalent Mach-Zehnder interferometer 61 can also be combined with a 90-degree pre-packaged miniature flexible waveguide to be applied to a short device in which each guide portion is exposed at a right angle to each other. The interferometer 610 includes optical fibers 612 and 614 mounted on a right-angle substrate 616. Each of the optical fibers 612 and 614 includes an optical transmission core 618 and a concentric coating 620. The first optical fiber 612 defines a first interference arm 623, and the second optical fiber 614 defines a second chirping arm 625, and extends between the first and second couplers 622 and 624. The interference arm 623 includes a first 90-degree miniature flexible waveguide 630 'between the couplers 622 and 624. Similarly, the optical fiber 614 includes a second 90-degree miniature flexible waveguide 632 between the couplers 622 and 624. The miniature flexible waveguide 630 is nested by the miniature flexible waveguide 632. In this case, the difference in path length between the optical fibers is established by different f-curvature radii of the miniature flexible waveguides 630 and 632. This paper size applies the Chinese National Standard (CNS) Al specification (210 x 297 mm) {Please read the precautions on the back before filling this page). Il — J — — — Order-------- · Duo printed by the Intellectual Property Bureau of the Ministry of Economic Affairs, printed by the consumer cooperative of the Intellectual Property Bureau of the Economic Village, printed by 4557 1 6 A1 I —___ B7_ V. Description of the invention (9) Miniature flexible waveguides 632 and 634 are ideally pre-packaged into The fixed pre-bent structure with protective shells 636 and 638 is used to assemble the optical fiber on the substrate 616 and coupled between the couplers 622 and 624. First, flexible waveguides 630 and 632 are manufactured, and then packaged in individual protective cases 636 and 638. Therefore, the housing 636 provides a pair of optical fiber guides 612a and 612t at the opposite ends of the first optical fiber 612, and the housing 638 provides a pair of optical fiber guides 614a and 614b at the opposite ends of the second optical fiber 614. Thereafter, the guides of the packaged miniature flexible waveguide are combined to form the couplers 622 and 624. The phase-sensitive area of the interferometer is defined by an optical fiber extending between couplers 622 and 624. In order to avoid contact with the base plate 616, the couplers 622 and 624 are preferably suspended at a position of a fiber diameter distance above the base plate 616 ', and the miniature flexible waveguides 630 and 632 are preferably suspended in the individual housings 636 and 638. Referring to FIGS. 8 to 10, the present invention also provides a device for forming a solid non-equivalence Mach-Zehnder interferometer in a small unilateral structure by using an unpackaged miniature flexible waveguide 'disposed in a phase-sensitive area. Unpackaged Miniature Flexible Waveguide Guides Use two couplers across four guides to form the sensitive area of the interferometer. In this architecture, because the miniature flexible waveguide has no other packaging, the coupler is an integral part of the miniature flexible structure. Since the miniature flexible waveguide is not packaged, the quality of the bonding of the phase-sensitive area of the interferometer circuit is substantially reduced. The shape of the substrate can be selected to be smaller, heat sensitive and vibration sensitive. Referring to FIG. 8, the present invention provides an optical fiber Mach-Zehnder interferometer 3 ι including a first extension optical fiber 312 and a second extension optical fiber 314 fixed to an extension substrate 316. Each of the optical fibers 312 and 314 includes an optical transmission core 318 and a concentric coating 320. The optical fibers 312 and 314 are optically coupled to the two couplers 322 and 324, and use the first tack 324 formed of epoxy resin and the paper size formed of gel_Medium_ 家 鲜 (CN ^ X4 秘 ⑵ ^ χ Norwegian public hair)

_I (Please read the notes on the back before filling this page)

45 57 l Q A7 __B7__ 5. Description of the invention () The epoxy resin tack 326 is fixed on the base plate 316, and the optical fibers 312 and 314 are gently fixed between the couplers 322 and 324. Since the optical fibers 312 and 314 are not rigidly fixed by the epoxy resin tack 324, the gel of the tack 326 reduces the thermal sensitivity of the interferometer. The first optical fiber 312 is defined by the second optical fiber 314 between the first and second couplers 322 and 324. The optical fiber 312 includes a first interference arm 323 extending between the couplers 322 and 324. The interference arm 323 includes a micro-flexible waveguide 33 formed. Similarly, the optical fiber M4 also includes an interference arm 325 extending between the couplers 322 and 324. The interference arm 325 also includes a micro-flexible waveguide 332 formed. Miniature flexible waveguides 330 and 332 are preferably unpackaged in advance to form an interferometer 310 'to reduce the quality of the fiber optic material. The miniature flexible waveguides 330 and 332 are arbitrarily supported across the boundary of the substrate 316. Referring to FIG. 9, the present invention also provides another fiber Mach-Zehnder interferometer 710 'including a first extension fiber 712 and a second extension fiber 714 fixed to an extension substrate 716. Each of the optical fibers 712 and 714 includes an optical transmission core 718 and a concentric coating 720. The first optical fiber 712 is drummed between the first and second couplers 722 and 724 on the second optical fiber Ή4. The optical fiber 712 includes a first interference arm 723 extending between the couplers 722 and 724. The interference arm 723 includes a micro-flexible waveguide 730 formed. The optical fiber 714 also includes a second interference arm 725 extending between the couplers 722 and 724. Moreover, the 'interference arm 725 also includes the formed miniature flexible waveguide 732. The miniature flexible waveguides 730 and 732 are preferably supported at a predetermined distance above the plane 716a of the substrate 716. The optical fibers 712 and 714 are optically light-coupled to the first and second couplers 722 and 724, and are fixed on the substrate 716 by using the first epoxy-based resin tack 726 and the gel tack 728. The epoxy resin pin 726 is located approximately at the free ends of the optical fibers 712 and 714. Gel tacks 728 are the most embarrassing. The paper size is applicable to China National Standard (CNS) A4 specifications (2〗 0 X 297). (Please read the precautions on the back before filling this page.) Pack --- 1-- -II Order --------- Consumption Cooperation between Employees and Intellectual Property Bureau of the Ministry of Economic Affairs 4557 1 6 ------- V. Description of the invention (11, near the positions of couplers 722 and 724, But by: = r-b epoxy-based tree-two :, interferometer 7U) also provides a thin metal sheet or platform on the substrate 716. The interference arms 723 and 725 are on the substrate 716. The pedestal 740 is preferably located near the rubber tack 728, so as to support the interference arms 723 and 725 at a position a predetermined distance above the base plate. The pedestal 740 also supplies the bonding agent by being in a proper position to help the supplied bonding agent be in a localized position. The surface tension between the gel tacks 728 and the pedestal 740 helps the gel to be localized so that it does not contact the processing area or coupler of the miniature flexible waveguide. In addition, the pedestal 740 can also be provided in any of the embodiments of Figs. 5 to 10, so as to support the interference arm and control the adhesive epoxy resin or gel in a suitable local position. In the embodiment of Figs. 8 to 10, the coupler can be simply supported on the substrate by an epoxy resin having a sticky side on one side and a gel or sticky epoxy based resin or a base on the other side. Referring to FIG. 10, a non-equivalent Mach-Zehnder interferometer 810 can also be combined with a 90-degree pre-packaged miniature flexible waveguide to be applied to a short device in which each guide portion is exposed at a right angle to each other. The interferometer 810 includes optical fibers 812 and 814 mounted on a right-angle substrate 816. Each of the optical fibers 812 and 814 includes an optical transmission core 818 and a concentric coating 820. The first optical fiber 812 and the second optical fiber 814 define a first interference arm 823 and a second interference arm 825 extending between the first and second couplers 822 and 824, respectively. The interference arm 823 includes a first 90-degree miniature flexible waveguide 83 in the middle of the couplers 822, 824, and the optical fiber 814 also includes a second 90-degree miniature flexible waveguide 832 in the middle of the couplers 822, 824. The miniature flexible waveguide 830 is nested by the miniature flexible waveguide 832. In this embodiment, the paper size of the paper is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 public love) f Please read the phonetic on the back? Matters need to be filled in this I ')

-------- " • Order --I ---- --- I Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economy 455? I 6 u Λ7 --------- B7__ 5 Explanation of the invention (12) The difference in path length between the fibers is established by the different bending radii of the miniature flexible waveguides 83 and 832. Moreover, the interferometer 810 provides viscous tacks at the relative positions of the phase sensitive areas of the optical fibers 812 and 814, thus avoiding the need to tack the interference arms of the phase sensitive areas tacky. As shown in Figures 8 to 10 'The viscous epoxy resin tack used between the coupler and the miniature flexible waveguide, as shown in the interferometer 51 〇, can also Light weight is omitted. Alternatively, the epoxy resin used between the coupler and the miniature flexible waveguide of the interferometer 51 can be replaced by a gel, thereby gently fixing the optical fiber without thermal sensitivity due to the stress of the bonding agent. Due to its lighter weight and lower inertial force, the gel is a suitable packaging device for the present invention. Therefore, a gel with a lower mechanism (m0 (juli) is a suitable joining medium. Moreover, the resulting structure is small and easy to assemble at the same time. Moreover, the material of the miniature flexible waveguide needs to be limited and must be large In order to reduce the stress caused by heat, it is also possible to consider using a low-stress bonding agent other than a gel to attach the optical fiber to the substrate without causing abnormal thermal effects or mechanical effects. The gel or epoxy resin can be used An optical fiber used in the area between the coupled coupler and the miniature flexible waveguide. However, if it is directly applied to the coupler or flexible waveguide, the epoxy resin may cause the weight loss of the device because the optical fiber The area will be modified to allow the optical field to become important on the outer edge of the fiber. Furthermore, the combined architecture can be made quite small, so not only improves the thermal stability of the interferometer but also reduces its appearance. In this architecture, the actual The facet joint area and the miniature flexible waveguide should not be in contact with materials other than extremely low refractive index and low loss materials such as air, otherwise, the refractive index is higher than 1 The material contact of 3 will cause the loss of the coupler or the miniature flexible waveguide.-The paper size on the outer side is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 public copy) (Please read the precautions on the back before filling in this Page) 裒 --------- Order --------- line — printed by the Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs Λ7 4557 1 6 V. Description of the invention (13) Packaging (not shown) ) Can also be arranged on a common substrate to provide a single interferometer package by avoiding contact with the miniature flexible waveguide. As shown in Figures 7 to 10, if the optical fiber is adhered and fixed to the common substrate, the interferometer of the present invention will Or the thermal expansion of the bonding agent used and the physical tensile force added to the fiber are sensitive to thermal anomalies. Therefore, the bonding agent becomes a potential cause of thermal sensitivity and phase instability. In an interferometer, any Forces outside the phase-sensitive region between the couplers will cause different phase shifts in the light traveling between the two compartments. Different phase shifts can be caused by changes in length or bending of different path length materials, or by Section The change in the refractive index varies between the factors. The change in the coefficient is related to the stress applied by the optical stress characteristics of the optical fiber. Since the stress applied by the bonding agent generally changes with temperature, the optical fiber will have a change in length and refractive index. Due to this thermally sensitive result, any epoxy-based resin or cement that is in contact with the fiber in the phase-sensitive area may cause different phase shifts when the light is transmitted through the fiber. The interferometer of the present invention can select a suitable thermal expansion coefficient Fiber and the appropriate fiber length between couplers to create a lower thermal sensitivity. The non-equivalence configuration between couplers must allow longer feet to have greater thermal expansion than shorter feet. Generally speaking, ' The thermal expansion of an optical fiber can be expressed as:

a) DeltaL = a * L * DeltaT where DeltaL is the increased physical length of the fiber section between the couplers 'a is the coefficient of thermal expansion' L section length between the couplers, and the temperature change is . The difference in dilation given to the interferometer's wavelength dependence is increased by changes in temperature. This wavelength dependence is determined by the phase through the fiber section between the couplers. The phase is: This paper size applies Chinese National Standard (CNS) A4 specification (21〇χ 297 mm) " Please read the notes on the back before filling this page) -I -----. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 455716

V. Description of the invention (l4) b) Phase = 2 * PI * n * L / Lambda where PI is a constant 'η is the refractive index of the segment, L is the segment length, and Lambda is the wavelength. In order to maintain the wavelength dependence of the interferometer from temperature changes, the phase change in the first section must be equal to the phase change in the second section; that is, c) Phasel = Phase2 Usually this phase is stable and not satisfied with the integrated interferometer. Therefore, the integrated device may show some residual temperature sensitivity due to changes in wavelength and refractive index with temperature. The present invention provides a non-equivalent folded Mach-Zehnder interferometer, which can be made non-thermal sensitive by selecting the appropriate length and refractive index between the coupler sections. In order to make phase relationship (c) not affected by temperature, it must meet the following formula: d) nl * dLl / dT + Ll * dnl / dT = n2 * dL2 / dT + L2 * dn2 / dT where 'd / dT is the temperature Derivative function. Therefore, the present invention manufactures a thermally stable interferometer by selecting an appropriate length between optical fiber sections and a refractive index, and its temperature derivative function according to the relationship (d). This relationship can be simplified by approximating different conditions. By formula (a) and let nl = n2, formula (d) can be approximated as: e) nl * LI + Ll * dnl / dT = n2 * aL2 + L2 * dn2 / dT or

f) nl * a * (LI-L2) = L2 * dn2 / dT-Ll * dnl / dT The thermal stability can be increased by choosing an optical fiber that meets these relationships. Often 'because one foot must be longer than the other to provide the required phase mismatch', the longer foot will have a larger phase change due to the physical extension of the segment. So the best match can be achieved by assembling shorter feet with larger thermally dependent refractive index. After that, the thermal insensitivity can be transferred to the paper size by using the longer extension phase of the longer section. The Chinese national standard (CNS > A4 specification (210x297 mm) is applied. (Please read the precautions on the back before filling this page). · ------- Order --------- «Printed by a member of the Intellectual Property Bureau of the Ministry of Economic Affairs and a Consumer Cooperative ^ 455716 Α7 Β7 V. Description of the invention (15) Moved to offset the high temperature of short feet The dependence coefficient is reached β and it should be noted that only the section between the couplers will provide the thermal effect of the phase, because the light in this area will travel through the two fibers and cause interference in the second fiber. The preferred embodiment of the invention, but without departing from the spirit of the present invention, those skilled in the art can make various modifications or changes. The above content and drawings are only examples and do not limit the invention. The actual scope of the invention is It is defined by the scope of the following patent applications: l · .---------------------------------------. Please fill in this page for attention. ≫ Printed by the Consumers' Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs. (CNS) A4 specifications (210 X 297 mm) 455716 A7 B7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 5. Description of the invention (0) Component symbol comparison table 12 Optical fiber 14 Optical fiber 1 6 Phase sensitive area 18 Phase sensitive area 22 Light coupler 24 coupler 1 10 interferometer 112 optical fiber 114 optical fiber 116 handle coupler 118 coupler 120 interference arm 122 interference arm 124 emblem flexible waveguide 126 miniature flexible waveguide 210 interferometer 2 12 optical fiber 2 14 optical fiber 216 Light coupler 2 18 Coupler 220 Interfering arm 222 Interfering arm 224 Miniature flexible waveguide 228 Miniature flexible waveguide 410 Interferometer 412 Optical fiber 414 Optical fiber 4 1 6 Right angle substrate 418 Optical transmission core 420 Concentric coating 423 Interference Arm 425 interference arm 430 interference arm 432 interference arm 5 10 interferometer 5 12 optical fiber 5 12a optical fiber guide 5 12b optical fiber guide 5 14 optical fiber 514a optical fiber guide 5 14b optical fiber guide 516 substrate 5 18 optical transmission core 520 Concentric Covers < Please read the note on the back before filling this page) -------- Order --------- 嫂-This paper size applies to China Standard (CNSXA4 specification (210 X 297 mm) 455716 A7 B7 V. Description of the invention (0 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 522 Coupler 524 Coupler 526 Epoxy resin tack 528 Epoxy resin head 530 Miniature Flexible Waveguide 532 Miniature Flexible Waveguide 536 Housing 538 Housing 610 Interferometer 6 12 Fiber 612a Fiber Guide 612b Fiber Guide 6 1 4 Fiber 6 14a Fiber Guide 614b Fiber Guide 6 1 6 Right-angle substrate 6 1 8 Optical transmission core 620 Concentric coating 622 Coupler 623 Interferometer 624 Coupler 625 Interferometer 630 Miniature flexible waveguide 632 Miniature flexible waveguide 636 Housing 638 Housing 3 10 Interferometer 3 12 Optical fiber 3 14 Optical fiber 3 16 Substrate 3 1 8 Optical transmission core 320 Concentric coating 322 Coupler 323 Interfering arm 324 Coupler 325 Interfering arm 326 Tack 330 Miniature flexible waveguide 332 Miniature flexible waveguide 7 10 Interferometer 7 12 Optical fiber 714 Fiberless 7 1 6 Substrate 7 18 Optical transmission core 720 Concentric coating 722 Couplings 723 Interference arms 724 Couplings suitable for China ? : Standard (CNU A4 specification (210 X 297 public love) ------------ M -------- fST --------- ^. (Please read first Note on the back, please fill out this page again) A7 ^ 455716 ----- B7 V. Description of the invention (U) The Intellectual Property Bureau of the Ministry of Economic Affairs Employee Co-operative Printing System Rule Sheet Paper 725 Interference Arm 726 Epoxy Resin Tack 728 Gel tack 730 Miniature flexible waveguide 732 Miniature flexible waveguide 740 Stand 8 10 Interferometer 8 12 Optical fiber 8 14 Optical fiber 8 16 Right angle substrate 8 18 Optical transmission core 820 Concentric coating 822 Coupler 823 Interference arm 824 Coupling 825 Interfering arm 830 Miniature flexible waveguide 832 Miniature flexible waveguide grid A4 s) N (c Standard :: Jiali 7V-I ττ < Please read the precautions on the back before filling this page)

Claims (1)

Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs for consumer cooperation ^ 45 5 7 1 6 os __ _D8 VI. Patent application scope 1 'A fiber-optic Mach-Zehnder interferometer, including: the first and second extension optical fibers, with core and Covering; first and first couplers, wherein the covering of the first optical fiber is coupled to the covering of the second optical fiber; a first extended interference arm including the first first extending between the first and second couplers An optical fiber, wherein the first interference arm includes a miniature flexible waveguide formed therein; and a second extended interference arm including the second optical fiber extending between the first and second couplers. 2. The fiber-optic Mach-Zehnder interferometer described in item 1 of the scope of the patent application, wherein the aforementioned first interference arm includes more than one micro-flexible waveguide formed in its order. 3. The fiber-optic Mach-Zehnder interferometer described in item 1 of the scope of the patent application, wherein the second interference arm includes a miniature flexible waveguide formed therein. 4. The fiber-optic Mach-Zehnder interferometer described in item 3 of the scope of the patent application, wherein the miniature flexible waveguide of the first interference arm is nested in the miniature flexible waveguide of the second interference arm. 5. The fiber-optic Mach-Zehnder interferometer described in item 4 of the scope of the patent application, wherein the aforementioned miniature flexible waveguides of the first and second optical fibers are pre-packaged miniature flexible waveguides, wherein each of the aforementioned miniature The flexible waveguide is supported in a protective casing, so that the opposite end of each of the optical fibers protrudes from the protective casing, so that the positions of the first and second couplers can be adjusted by the first and second pre-packaged miniature The paper size of the protective casing of the curved waveguide is in accordance with the Chinese National Standard (CNS) A4 specification (21〇X 297 meals) (Please read the precautions on the back before filling this page) ^ -------- -Order --------- Line — 45 5 7 1 6 A8 B8 C8 D8 VI. Scope of patent application Employees in the Intellectual Property Bureau of the Ministry of Economic Affairs shall select the length of separation between consumption and printing. 6. The fiber optic Mach-Zehnder interferometer described in item 1 of the scope of the patent application, wherein the aforementioned first and second optical fibers are mounted on an extension substrate. 7. The first and second ends of the aforementioned first and second optical fibers in the optical fiber Mach-Zehnder interferometer described in item 6 of the scope of the patent application extend beyond one end of the aforementioned substrate. 8. The optically woven Mach-Zehnder interferometer described in item 4 of the scope of the patent application, wherein the aforementioned first-fiber optical fiber micro-flexible waveguide material is about 180 degrees. 9. The fiber optic Mach-Zehnder interferometer as described in item 6 of the Shenjing patent scope, where the 〃jit-second optical fiber n extends over one end of the aforementioned substrate, and the aforementioned second ends of the first and second optical fibers extend The first edge of the H substrate passing through the H substrate is not opposed to the second edge of the substrate. 10. The fiber-optic Mach-Zehnder interferometer described in item 4 of the scope of the patent application, wherein the miniature flexible waveguide of the first optical fiber bends the first optical fiber by approximately 90 degrees. 11. The fiber-optic Mach-Zehnder interferometer described in item 6 of the scope of the patent application, wherein the micro-flexible waveguide of the first optical fiber bends the first optical fiber to form a micro-flexible wave with a bend radius larger than that of the second optical fiber. The bend radius of the catheter. 12. The fiber-optic Mach-Zehnder interference instrument described in item 6 of the scope of the patent application, wherein the first and second optical fibers are adhered and fixed on the substrate, and the phase-sensitive area is relative to the first and second handles. Position of the coupler, and the first optical fiber just described is intended to be placed between the aforementioned first and second couplers ^ --------- order --------- line-( (Please read the notes on the back before filling out this page) nnnf— Standards of this paper_Chinese National Standard (CNS) A4 Specification ⑵〇 x Nokia 4557 1 Q Sixth, the scope of patent application 13 14 15 16 17 The aforementioned second optical fiber. For example, if the scope of the patent application is No. 6, the needle n refers to the angle of the already loaded fiber Mach-Zehnder interferes with its cylinder—and the second fiber is fixed on the aforementioned substrate along the aforementioned phase-sensitive area by a viscous gel. position. Xun Yiyi as described in Shenwei Item 6 _ Mach-Zehder Interference L-; :: at least-fiber in the coffee area extends beyond the fiber optic horse described in the aforementioned base instrument as described in Item 1 of the scope of Shen Er patent. In Interference 2, the first extension optical fiber displays a first thermal expansion coefficient; the second extension optical fiber displays a second thermal expansion coefficient, and the first thermal expansion coefficient is greater than the second thermal expansion coefficient; wherein the first-fiber is coupled to the first and second Are nested between the aforementioned second optical fibers. 2. The fiber-optic Mach-Zehnder interferometer described in item 15 of the scope of the patent application, where the aforementioned first and second optical fibers and interference arms are selected according to the following formula: nl * dLl / dT + Ll * dnl / dT = n2 * dL2 / dT + L2 * dn2 / dT where d / dT represents the temperature derivative function 〇1 is the refractive index of the aforementioned first interference arm 'L1 is the length of the aforementioned -interference arm 丨' n2 is the refractive index of the aforementioned second interference arm , L2 is the length of the aforementioned second interference arm. The optical fiber Mach ^ del interferometer described in item 15 of the scope of the patent application, wherein the first and second optical fibers and the interference arm are selected according to the following formula: nl * a * (LI-L2) = L2 * dn2 / dT —Ll * dnl / dT where nl is the refractive index of the aforementioned first and second optical fibers, a is the thermal expansion coefficient of the aforementioned optical fiber, L1 is the length of the aforementioned first interference arm, and the paper size of the clothing line is applicable to the national specimen (CNS) A4 size mo X 297 mm ^ 45 57 1 q Scope of patent application The length of the second interference arm, the resistance indicates the temperature derivative function, the refractive index of the cutting arm of the step arm, and n2 represents the refractive index of the aforementioned second interference arm. The fiber optic Mach-Zehnder interferometer described in the application section ⑽ 帛 丨, wherein the aforementioned first and second couplers are asymmetric. 1: Middle: The fiber-optic Mach-Zehnder interferometer described in item 1 of patent 1a, wherein the aforementioned first and second consumers are symmetrical. 20. The Chan Mach-Zehdel interference recorded in item i of the H-Li range also includes a third optical fiber, in which at least one of the aforementioned first, second, and third optical fibers is photosensitive. The optical fiber Mach-Zehnder rupture meter 'described in item 20 of the scope of the patent application, wherein at least one of the aforementioned first, second, and third optical fibers is photosensitive. The fiber-optic Mach-Zehnder interferometer described in item 1 of the scope of patent application, wherein the aforementioned first coupler shows a distribution ratio of about 0.05. 23. The fiber-optic Mach-Zehnder instrument as described in item i of the patent application scope, wherein the aforementioned first coupler shows a distribution ratio greater than 0. The fiber-optic Mach-Zehnder instrument described in the first patent application, wherein the aforementioned first and second couplers show different distribution ratios. The fiber-optic Mach-Zehnder interferometer described in item 1 of the patent application range, wherein the aforementioned first and second interference arms are unbalanced. "As described in Item 1 of the scope of the patent application, the optical fiber Mach-Zehnder tenth instrument also includes an optical fiber Bragg grid plate located adjacent to each of the aforementioned first and second couplers. Σ (please first Read the notes on the back and fill out this page) 21 22 24-1-^ ---- r --- Order --------- line | Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs Consumer Cooperatives 25 26