Optical integration device and optical time domain reflectometer

Abstract

The invention provides an optical integration device and an optical time domain reflectometer. The optical integration device comprises a packaging shell, a first collimator, a light splitting device, a circulator assembly and a second collimator. The light splitting device is arranged close to the first collimator and used for reflecting part of the detection light from the first tail fiber to the third tail fiber, and the other part of the detection light penetrates through the light splitting device. The circulator assembly is arranged close to the light splitting device, and the circulator assembly is used for coupling the detection light penetrating through the light splitting device to the second tail fiber and then coupling the detection light from the second tail fiber to the third tail fiber. According to the optical integration device, the light splitting device and the ring device are integrated and packaged in the packaging shell, so that the number of parts of the optical time domain reflectometer and the number of fiber welding contacts can be reduced, the space can be saved, and the performance can be improved.

Description

Technical Field

[0001] This application relates to the field of optical technology, and in particular to an optical integrated device and an optical time domain reflectometer. Background Technology

[0002] An optical time domain reflectometer (OTDR) is a precision optoelectronic instrument that utilizes the backscattering caused by Rayleigh scattering and Fresnel reflection of light propagating in optical fibers. It is widely used in the maintenance and construction of optical cable lines to measure fiber length, transmission attenuation, splice attenuation, and fault location. The OTDR uses a synchronous clock to record the time of pulsed laser light as a reference time. It then records the time of the pulse reflected back from the break point in the faulty fiber, comparing this time with the reference time to obtain the time difference. Based on this time difference, the location of the fiber optic fault break point can be calculated.

[0003] Currently, optical time-domain reflectometers (OTDRs) typically consist of multiple independent optical components such as beam splitters and circulators, and pulsed laser transmission is achieved through fiber optic splicing nodes. These multiple splicing nodes occupy space within the OTD, increasing its overall size. Furthermore, splicing multiple splicing nodes is complex, and these nodes are prone to transmission loss and connection instability, affecting the OTD's performance and reliability. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a small-sized and simple optical integration device and an optical time-domain reflectometer.

[0005] An optical integration device is used to decompose detection light from a first pigtail and couple it to a second pigtail and a third pigtail respectively, and to couple detection light returning from the second pigtail to the third pigtail; comprising: A packaged outer casing; A first collimator, a beam splitter, a circulator assembly, and a second collimator are sequentially disposed within the encapsulation housing; The beam splitter is positioned close to the first collimator and is used to reflect and couple a portion of the detection light from the first pigtail to the third pigtail, while the other portion of the detection light passes through the beam splitter. The circulator assembly is positioned close to the beam splitter and is used to couple the detection light transmitted through the beam splitter to the second pigtail, and to couple the detection light returned from the second pigtail to the third pigtail.

[0006] In one embodiment, the beam splitter has a beam splitting film on the surface facing the first collimator, and a filter film on the other opposite surface facing the circulator assembly.

[0007] In one embodiment, the detection light returning from the second pigtail first passes through the circulator assembly, then through the beam splitter before being coupled to the third pigtail, and the filter film is used to filter out other signal light from the second pigtail besides the detection light.

[0008] In one embodiment, the beam splitter is used to partially reflect the detection light at a wavelength of 1510 nm, and the filter is used to filter the signal light at a wavelength of 1550 nm.

[0009] In one embodiment, the circulator assembly includes a first birefringent crystal, a first half-wave plate, a first Faraday rotator plate, a Wollaston prism, a second Faraday rotator plate, a second half-wave plate, and a second birefringent crystal arranged sequentially from front to back.

[0010] In one embodiment, the encapsulation housing includes a first encapsulation tube and a second encapsulation tube disposed on one side of the first encapsulation tube, the first collimator is housed in the first encapsulation tube, and the beam splitter and the circulator assembly are both housed in the second encapsulation tube.

[0011] In one embodiment, the optical integration device further includes a third encapsulation tube disposed on the other side of the second encapsulation tube and a second collimator housed within the third encapsulation tube.

[0012] In one embodiment, a carrier plate is disposed inside the second encapsulation tube. One side of the carrier plate is used to fix the beam splitter and the circulator assembly, while the other side of the carrier plate is fixed to the inner wall of the second encapsulation tube.

[0013] An optical time-domain reflectometer includes at least: a laser emitting unit, an optical integration device, and a photoelectric conversion device; The laser emitting unit is used to emit a detection light to the optical integration device; The optical integration device decomposes the detection light into a first detection light and a second detection light; wherein, the first detection light is directly output to the photoelectric conversion device, and the second detection light is output to a fiber under test after passing through the optical integration device; the optical integration device is also used to output the second detection light returned from the fiber under test to the photoelectric conversion device. The photoelectric conversion device is used to convert the first detection light into a first electrical signal and the returned second detection light into a second electrical signal.

[0014] In one embodiment, the optical time domain reflectometer further includes a signal processing unit for processing the first electrical signal and the second electrical signal.

[0015] In one embodiment, the optical time-domain reflectometer further includes a pulse generator that provides a pulse signal to the laser emitting unit and the signal processing unit.

[0016] As can be seen from the above technical solution, this application has at least the following advantages and positive effects: This application provides an integrated optical device that integrates a beam splitter and a ring device into a single package, forming a unified optical device. This reduces the number of fiber optic connections in an optical time-domain reflectometer (OTDR), saving space and reducing the overall size of the integrated device. Furthermore, the free-space optical coupling structure of the beam splitter and ring device reduces the number of fiber optic connections, simplifying the manufacturing process and lowering costs, while also improving system performance and reliability. Moreover, the reduced volume of the integrated device in the OTD contributes to a smaller overall size and lower cost, facilitating the miniaturization of the OTD. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the functional modules of an optical time-domain reflectometer according to a preferred embodiment of the present invention; Figure 2 A perspective view of an optical integration device according to a preferred embodiment of the present invention; Figure 3 According to Figure 2 A cross-sectional view of the optical integration device shown; Figure 4 According to Figure 2 A cross-sectional view of the optical integration device shown from another angle; Figure 5 According to Figure 2 A simplified optical path diagram of the optical integration device shown; Figure 6 According to Figure 3 The diagram shows the structure of the optical integration device. Figure 7 According to Figure 3 The diagram shows the structure of the optical integration device. Figure 8 According to Figure 7 The diagram shows the polarization state change of the second detection light from the first pigtail to the second pigtail. Figure 9 According to Figure 7The diagram shows the polarization state change of the second detection light from the second pigtail to the third pigtail.

[0018] The annotations in the attached figures are explained as follows: 1. Laser emitting unit; 2. Optical integration device; 3. Photoelectric conversion device; 4. Signal processing unit; 5. Pulse generator; 6. Fiber under test; 10. Optical time domain reflectometer; 211. First pigtail; 213. Third pigtail; 212. Second pigtail; 214. Two-hole ceramic ferrule; 215. Single-hole ceramic ferrule; 22. Encapsulation shell; 221. First encapsulation tube; 222. Second encapsulation tube; 223. Third encapsulation tube; 224. First sleeve; 225. Second sleeve; 23. First 24. Collimator; 24. Beam splitter; 241. Beam splitter film; 242. Filter film; 25. Circulator assembly; 251. First birefringent crystal; 252. First half-wave plate; 253. First Faraday rotator plate; 254. Polarizing prism; 255. Second Faraday rotator plate; 256. Second half-wave plate; 257. Second birefringent crystal; 258. Magnetic ring; 259. Compensator plate; 26. Second collimator; 27. Carrier plate; L. Detection beam; L1. First detection beam; L2. Second detection beam. Detailed Implementation

[0019] Typical embodiments embodying the features and advantages of this application will be described in detail in the following description. It should be understood that this application can have various variations in different embodiments, all of which do not depart from the scope of this application, and the descriptions and illustrations therein are for illustrative purposes only and not intended to limit this application.

[0020] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0021] Reference Figure 1A preferred embodiment of this application provides an optical time domain reflectometer 10. The optical time domain reflectometer 10 includes a laser emitting unit 1, an optical integration device 2, a photoelectric conversion device 3, a signal processing unit 4, and a pulse generator 5.

[0022] The signal processing unit 4 controls the pulse generator 5 to emit a pulse electrical signal with a certain frequency and adjustable pulse width, thereby driving the laser emitting unit 1 to generate the required power optical pulse.

[0023] The laser emitting unit 1 emits a detection light to the optical integration device 2. Specifically, in this embodiment, the laser emitting unit 1 emits a detection light with a wavelength of 1510 nm. It is understood that the laser emitting unit 1 can be a laser diode, laser, etc. In other embodiments, the laser emitting unit 1 can also emit detection light of other wavelengths as needed.

[0024] Please refer to Figure 2 The optical integration device 2 extends outward with three pigtails, of which the dual-fiber pigtails at the front end of the optical integration device 2 include a first pigtail 211 and a third pigtail 213; while the single-fiber pigtail at the rear end of the optical integration device 2 is a second pigtail 212.

[0025] The first pigtail 211 can be directly connected to the laser emitting unit 1 to receive the detection light L. The third pigtail 213 is an output pigtail used to output an optical signal with the required wavelength to the photoelectric conversion device 3. The second pigtail 212 is used for optical coupling to a fiber optic cable 6 under test. The optical integration device 2 is used to decompose the detection light from the first pigtail 211 and couple it to the second pigtail 212 and the third pigtail 213 respectively, and to couple the detection light returning from the second pigtail 212 to the third pigtail 213.

[0026] Please also refer to Figure 3 and Figure 4 Specifically, in this preferred embodiment, the optical integration device 2 includes a package housing 22, a first collimator 23, a beam splitter 24, a circulator assembly 25, and a second collimator 26. The first collimator 23, beam splitter 24, circulator assembly 25, and second collimator 26 are sequentially arranged within the package housing 22. The beam splitter 24 is used to decompose the detection light L emitted by the laser emitting unit 1 into a first detection light L1 and a second detection light L2. The first detection light L1 is directly reflected to the photoelectric conversion device 3, while the second detection light L2 is output to the optical fiber 6 under test through the circulator assembly 25. The circulator assembly 25 can also be used to output the second detection light L2 reflected back from the optical fiber 6 under test to the photoelectric conversion device 3.

[0027] The photoelectric conversion device 3 is used to convert the first detection light L1 into a first electrical signal and the second detection light L2, which is later reflected back, into a second electrical signal.

[0028] Please refer to it again. Figure 1 The aforementioned optical time-domain reflectometer further includes a signal processing unit 4. The signal processing unit 4 processes the first electrical signal and the second electrical signal. Based on the first and second electrical signals, the signal processing unit 4 calculates the optical path difference between the first detection light L1 and the second detection light L2 reflected back from the fiber under test 6. This allows it to determine the transmission status of the second detection light L2 in the fiber under test 6 and calculate the positions of each reflecting end face of the fiber under test 6, thereby enabling measurements of fiber length, fiber transmission attenuation, connector attenuation, and fault location.

[0029] Please refer to it again. Figure 2 Specifically, in this embodiment, the encapsulation shell 22 is the external structure of the optical integration device 2, used to protect the internal optical components. Furthermore, the encapsulation shell 22 must remain sealed and dustproof to ensure the lifespan of the optical integration device 2. Specifically, in this embodiment, the encapsulation shell 22 includes a first encapsulation tube 221, a second encapsulation tube 222, and a third encapsulation tube 223. The first encapsulation tube 221 is disposed near the first pigtail 211 and the third pigtail 213, and the third encapsulation tube 223 is disposed near the second pigtail 212. The first pigtail 211 and the third pigtail 213 are fixed to one end of the first encapsulation tube 221 by a double-hole ceramic ferrule 214. The second pigtail 212 is fixed inside the third encapsulation tube 223 by a single-hole ceramic ferrule 215.

[0030] Please refer to it again. Figure 4 The first collimator 23 is positioned close to the first pigtail 211 and the third pigtail 213. The first collimator 23 is used to collimate the detection light L input from the first pigtail 211 and output collimated detection light parallel to the axis. Preferably, the first pigtail 211 and the third pigtail 213 are located at the front focal plane of the first collimator 23, minimizing the overall optical system loss. Furthermore, the first collimator 23 is also fixed within the first encapsulation tube 221.

[0031] The second collimator 26 is positioned close to the second pigtail 212. The second collimator 26 is used to collimate the beams output from and returned by the second pigtail 212, and output a collimated beam parallel to the axis. It is understood that the beam returning from the second pigtail 212 may include the second detection light L2 reflected from the reflective surface of the fiber under test 6 and the signal light S mixed within the fiber under test 6. The second collimator 26 and the second pigtail 212 are encapsulated within the third encapsulation tube 223.

[0032] Please also refer to Figure 5The beam splitter 24 is positioned close to the first collimator 23. The beam splitter 24 is used to separate the collimated detection light into a first detection light L1 and a second detection light L2. The first detection light L1 is directly reflected by the beam splitter 24 to the third pigtail 213, and the second detection light L2 passes through the beam splitter 24.

[0033] Specifically, in this embodiment, the beam splitter 24 is preferably a light-transmitting thin film, on one surface facing the first collimator 23, a beam splitting film 241 is provided. The beam splitter 24 has a filter film 242 on the other surface facing the circulator assembly 25. The filter film 242 is used to filter signal light from the second pigtail 212. The filter film 242 can prevent the signal light S in the fiber under test 6 from entering the third pigtail 213, thereby avoiding interference from the signal light S to the photoelectric conversion device 3 and preventing adverse effects of the signal light S on the detection results of the optical time domain reflectometer. In this embodiment, the beam splitter 24 can simultaneously have beam splitting and filtering functions, thereby saving space in the optical integration device 2, reducing the size of the optical integration device 2, and facilitating miniaturization design. It is worth mentioning that, in cases where signal quality requirements are not high, the filter film 242 can be omitted.

[0034] Specifically, in this embodiment, the beam-splitting film 241 is used to partially reflect the detection light L with a wavelength of 1510 nm. The filter film 242 is used to filter the signal light S with a wavelength of 1550 nm. It is understood that in other embodiments, depending on different needs, the beam-splitting film 241 can also partially reflect detection light of other wavelengths. Furthermore, the filter film 242 can also be used to filter signal light of other wavelengths. Therefore, the specific features of the beam-splitting film 241 and the filter film 242 are not limited here, as long as the beam-splitting film 241 can partially reflect the detection light and the filter film 242 can filter the signal light. It is understood that in this embodiment, the filter film 242 serves as... Figure 1 The optical filter 242 in the image has a function, but in other embodiments not shown, the filter film 242 may not be disposed on the other surface of the beam splitter 24, but may be an independent optical filter or optical filter sheet.

[0035] The circulator assembly 25 is positioned close to the beam splitter 24. Both the beam splitter 24 and the circulator assembly 25 are encapsulated within a second encapsulation tube 222. The second encapsulation tube 222 is preferably a glass tube.

[0036] The circulator assembly 25 is used to couple the second detection light L2, which is transmitted through the beam splitter 24, to the second pigtail 212. The second detection light L2 is reflected at the reflective end face of the fiber under test 6 and returns to the second pigtail 212. The circulator assembly 25 then transmits the second detection light L2 returned from the second pigtail 212 to the beam splitter 24. After passing through the beam splitter 24, it is coupled to the third pigtail 213.

[0037] Please also refer to Figure 6 and Figure 7 The circulator assembly 25 preferably includes two birefringent crystals (251, 257), two half-wave plates (252, 256), two Faraday rotators (253, 255), a polarizing prism 254, and a compensating plate 259.

[0038] The first birefringent crystal 251 is positioned close to the beam splitter 24, while the second birefringent crystal 257 is positioned close to the second collimator 26. The second detection light L2 is decomposed into o-ray and e-ray with mutually perpendicular polarization directions by the first birefringent crystal 251.

[0039] A polarizing prism 254 is disposed between the first birefringent crystal 251 and the second birefringent crystal 257. The polarizing prism 254 consists of two right-angle prisms with their crystal axes perpendicular to each other. The polarizing prism 254 can be a Wollaston prism or a Rochon prism.

[0040] The two Faraday rotators include a first Faraday rotator 253 and a second Faraday rotator 255. Preferably, the first Faraday rotator 253 and the second Faraday rotator 255 are respectively disposed on the end faces of the front and rear ends of the polarizing prism 254. Figure 3 or Figure 4 As shown, the magnetic ring 258 provides a magnetic field for the two Faraday rotators 253 and 255, enabling them to deflect the direction of polarized light. The magnetic ring 258 is preferably fitted into the middle of the second encapsulation tube 222 to facilitate the arrangement of optical components. Specifically, in this embodiment, both Faraday rotators 253 and 255 can rotate the polarization angle of the detected light by 45 degrees.

[0041] The first Faraday rotator 253 is disposed close to the first birefringent crystal 251. The second Faraday rotator 255 is disposed close to the second birefringent crystal 257. The first Faraday rotator 253 and the second Faraday rotator 255 can rotate the polarization direction of the second detection light L2 counterclockwise by 45 degrees.

[0042] Two half-wave plates 252 and 256 are disposed between the first birefringent crystal 251 and the second birefringent crystal 257. Specifically, in the optical path of the second detection light L2, the first half-wave plate 252 is preferably disposed between the first birefringent crystal 251 and the first Faraday rotator plate 253. The second half-wave plate 256 is preferably disposed between the second birefringent crystal 257 and the second Faraday rotator plate 255.

[0043] The first half-wave plate 252 is preferably attached to the rear end face of the first birefringent crystal 251 and occupies the lower half of the rear end face.

[0044] The circulator assembly 25 preferably also includes a compensation plate 259. The compensation plate 259 is attached to the rear end face of the first birefringent crystal 251 and occupies the upper half of the rear end face. The compensation plate 259 is located on the same plane as the first half-wave plate 252. The compensation plate 259 is used to make the optical path lengths of the o-ray and e-ray consistent, thereby mitigating the polarization dispersion problem of the second detection light L2.

[0045] The second half-wave plate 256 is preferably attached to the front end face of the second birefringent crystal 257, occupying the lower half of the front end face. The second half-wave plate 256 deflects the polarization direction of one of the polarized light paths. Attaching the second half-wave plate 256 to the second birefringent crystal 257 facilitates assembly and achieves better optical performance.

[0046] Therefore, the optical integration device 2 includes a beam splitter 24, a first birefringent crystal 251, a first half-wave plate 252, a first Faraday rotator 253, a polarizing prism 254, a second Faraday rotator 255, a second half-wave plate 256, and a second birefringent crystal 257 arranged sequentially from front to back.

[0047] like Figure 4 As shown, the aforementioned optical integration device 2 also includes a carrier plate 27. The beam splitter 24 and the circulator assembly 25 are both fixed to the upper side of the carrier plate 27. The lower side of the carrier plate 27 is fixed to the inner wall of the second encapsulation tube 222. The carrier plate 27 provides a stable mounting surface for the beam splitter 24 and the circulator assembly 25, allowing them to be integrally fixed to the carrier plate 27 during assembly. Then, the carrier plate 27 is positioned and fixed within the second encapsulation tube 222, facilitating assembly and accurate alignment.

[0048] Furthermore, specifically in this embodiment, the first encapsulation tube 221 is sealed to one end of the second encapsulation tube 222 via a first sleeve 224 fitted around its outer periphery. The third encapsulation tube 223 is sealed to the other end of the second encapsulation tube 222 via a third sleeve 225 fitted around its outer periphery. Moreover, the outer diameters of the first sleeve 224, the third sleeve 225, and the second encapsulation tube 222 are similar, allowing the optical integration device 2 to have a linear structure, resulting in simpler components and a simpler manufacturing process. Furthermore, the axes of the first collimator 23, the beam splitter 24, the circulator assembly 25, and the second collimator 26 are largely aligned, resulting in a smaller adjustment dimension and easier adjustment during angle adjustment. In some embodiments not shown, the first sleeve 224 and the third sleeve 225 can be omitted, and the first encapsulation tube 221, the second encapsulation tube 222, and the third encapsulation tube 223 can be sequentially connected as a single unit.

[0049] The polarization state of the second detection light L2 propagating within the optical integration device 2 will now be explained: Please see Figure 8 This is a diagram showing the polarization state change of the second detection light L2 from the first pigtail 211 to the second pigtail 212. Specifically, after passing through the beam splitter 24, the second detection light L2 is coupled to the circulator assembly 25. The second detection light L2 is then decomposed into o-rays and e-rays with mutually perpendicular polarization directions by the first birefringent crystal 251. Figure 8 As shown, the o-ray is above the e-ray. After passing through the first half-wave plate 252, the e-ray's polarization direction rotates 90 degrees, becoming the same as the o-ray's polarization direction. The o-ray and e-ray pass through the first Faraday rotator 253 and then rotate counterclockwise by 45 degrees. After passing through the Wollaston prism 23, the light propagation path is deflected. After the collimated light deflects, it passes through the second Faraday rotator 255, where the o-ray and e-ray continue to rotate counterclockwise by 45 degrees, their polarization directions changing from horizontal to vertical. The vertically polarized light below passes through the second half-wave plate 256, its polarization direction becoming horizontal, and for the second birefringent crystal 257, it becomes the o-ray. The vertically polarized light above does not pass through the second half-wave plate 256, thus maintaining its vertical polarization direction. Thus, the initial o-ray becomes the e-ray, and the initial e-ray becomes the o-ray. After passing through the second birefringent crystal 257, they converge and couple to the second pigtail 212.

[0050] like Figure 9 The diagram shows the polarization state change of the second detection light L2 as it returns from the second pigtail 212 to the third pigtail 213 in this embodiment. The second detection light L2, returning from the fiber under test 6, enters the second pigtail 212 and, after passing through the second birefringent crystal 257, is decomposed into o-ray and e-ray, with the e-ray above and the o-ray below. The o-ray, after passing through the second half-wave plate 256, becomes a vertical e-ray. Then, the o-ray and e-ray pass through the second Faraday rotator 255, rotating 45 degrees counterclockwise. After passing through the Wollaston prism 254, the beam path is deflected. The deflected second detection light L2 then passes through the first Faraday rotator 253, where the o-ray and e-ray continue to rotate 45 degrees counterclockwise. The horizontally polarized light below, after passing through the first half-wave plate 252, has its polarization direction rotated by 90 degrees, becoming vertically polarized light. Thus, the initial o-light becomes e-light, and the e-light becomes o-light. The two polarized beams then recombined into one beam after passing through the first birefringent crystal 251, and after passing through the beam splitter 24, are coupled to the third pigtail 213 and output to the photoelectric conversion device 3. The signal light S, doped in the second detection light L2, is filtered out by the filter film 242 of the beam splitter 24, thereby reducing noise.

[0051] Therefore, the optically integrated device 2 has at least the following advantages: First, this application integrates the beam splitter 24 and the circulator 25 into a single housing 22, forming a single optical integrated device 2. Therefore, when fabricating the optical time-domain reflectometer 10, it is only necessary to connect the first pigtail 211 to the laser emitting unit 1, the third pigtail 213 to the photoelectric conversion device 3, and the second pigtail 212 to the external port (not shown) corresponding to the fiber under test 6. This application integrates the beam splitter 24, optical filter 242, and circulator 25 into a single optical integrated device 2, reducing the number of independent components. Furthermore, this optical integrated device 2 uses free-space optical coupling to connect the beam splitter 24, optical filter 242, and circulator 25, rather than using conventional fiber optic connections. This reduces the number of fusion splice points during the fabrication of the optical time-domain reflectometer 10, saving space and facilitating miniaturization. Reducing fusion splice points also helps reduce optical loss at the fusion interface, improves optical performance, simplifies the fabrication process, and enhances system reliability.

[0052] The aforementioned optical time domain reflectometer 10 can measure the fault section of the optical fiber 6 under test using the optical integration device 2, avoiding interference from the interference signal light S in the link system to the photoelectric conversion device 3, which is beneficial to improving the accuracy of the optical time domain reflectometer.

[0053] Secondly, within the aforementioned optical integrated device 2, its beam splitter 24 can simultaneously perform beam splitting and filtering functions, which can save space in the optical integrated device 2, reduce its volume, and facilitate miniaturization design.

[0054] Although this application has been described with reference to several typical embodiments, it should be understood that the terminology used is descriptive and exemplary, and not restrictive. Since this application can be embodied in many forms without departing from its spirit or substance, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. An optical integration device, configured to decompose detection light from a first pigtail and couple it to a second pigtail and a third pigtail respectively, and to couple detection light returning from the second pigtail to the third pigtail; characterized in that, include: A packaged housing, wherein the first and third pigtails are fixed to one end of the packaged housing via a double-hole ceramic ferrule; A first collimator, a beam splitter, a circulator assembly, and a second collimator are sequentially disposed within the encapsulation housing. The first collimator is positioned close to the first pigtail and the third pigtail. The beam splitter is positioned close to the first collimator and is a light-transmitting thin film. The beam splitter has a beam-splitting film on its surface facing the first collimator and a filter film on its opposite surface facing the circulator assembly. The beam splitter is used to reflect and couple a portion of the detection light from the first pigtail to the third pigtail, while the other portion of the detection light passes through the beam splitter. The circulator assembly is positioned close to the beam splitter and is used to couple the detection light transmitted through the beam splitter to the second pigtail, and to couple the detection light returning from the second pigtail to the third pigtail.

2. The optical integrated device according to claim 1, characterized in that, The detection light returning from the second pigtail first passes through the circulator assembly, then through the beam splitter before being coupled to the third pigtail. The filter film is used to filter out other signal light from the second pigtail besides the detection light.

3. The optical integrated device according to claim 1, characterized in that, The optical integration device is linear, and the first and third pigtails are located at the front focal plane of the first collimator. The first collimator, the beam splitter, the circulator assembly, and the second collimator are aligned.

4. The optical integration device according to any one of claims 1 to 3, characterized in that, The circulator assembly includes a first birefringent crystal, a first half-wave plate, a first Faraday rotator plate, a Wollaston prism, a second Faraday rotator plate, a second half-wave plate, and a second birefringent crystal arranged sequentially from front to back.

5. The optical integration device according to claim 4, characterized in that, The encapsulation housing includes a first encapsulation tube and a second encapsulation tube disposed on one side of the first encapsulation tube. The first collimator is housed in the first encapsulation tube, and the beam splitter and the circulator assembly are both housed in the second encapsulation tube.

6. The optical integration device according to claim 5, characterized in that, The optical integration device also includes a third encapsulation tube disposed on the other side of the second encapsulation tube and a second collimator housed within the third encapsulation tube, wherein the second pigtail is fixed to the third encapsulation tube by a single-hole ceramic ferrule.

7. The optical integrated device according to claim 6, characterized in that, A carrier plate is disposed inside the second encapsulation tube. One side of the carrier plate is used to fix the beam splitter and the circulator assembly, while the other side of the carrier plate is fixed to the inner wall of the second encapsulation tube.

8. The optical integrated device according to claim 7, characterized in that, The carrier plate provides a stable mounting surface for the beam splitter and the circulator assembly, so that during assembly, the beam splitter and the circulator assembly can be fixed integrally onto the carrier plate first, and then the carrier plate can be positioned and fixed inside the second encapsulation tube, which facilitates assembly and accurate alignment.

9. An optical time-domain reflectometer, characterized in that, It includes at least: a laser emitting unit, an optical integration device as described in any one of claims 1-8, and a photoelectric conversion device; The laser emitting unit is used to emit a detection light to the optical integration device; The optical integration device decomposes the detection light into a first detection light and a second detection light; wherein, the first detection light is directly output to the photoelectric conversion device, and the second detection light is output to a fiber under test after passing through the optical integration device; the optical integration device is also used to output the second detection light returning from the fiber under test to the photoelectric conversion device. The photoelectric conversion device is used to convert the first detection light into a first electrical signal and the returned second detection light into a second electrical signal.

10. The optical time-domain reflectometer according to claim 9, characterized in that, The optical time-domain reflectometer further includes a signal processing unit, which is used to process the first electrical signal and the second electrical signal.

11. The optical time-domain reflectometer according to claim 10, characterized in that, The optical time-domain reflectometer also includes a pulse generator, which provides a pulse signal to the laser emitting unit and the signal processing unit.

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