Integrated tunable optical attenuator and method of making same

Abstract

The application provides an integrated adjustable optical attenuator and a manufacturing method thereof. The integrated adjustable optical attenuator comprises an input optical power detection unit, an output optical power detection unit and an integrated optical fiber assembly. The integrated optical fiber assembly has an input optical fiber head unit, an output optical fiber head unit and an intermediate optical fiber head unit, which respectively have a first ceramic ferrule, a second ceramic ferrule and a third ceramic ferrule. An input optical fiber is fixed to the first ceramic ferrule. Two ends of a first connecting optical fiber are fixed to the first ceramic ferrule and the third ceramic ferrule. Two ends of a second connecting optical fiber are fixed to the second ceramic ferrule and the third ceramic ferrule. An output optical fiber is fixed to the second ceramic ferrule. The input optical fiber head unit is coupled with the input optical power detection unit. The output optical fiber head unit is coupled with the output optical power detection unit. The intermediate optical fiber head unit is coupled with an adjustable optical attenuation unit. The application also provides a manufacturing method of the adjustable optical attenuator. The application can reduce the volume of the adjustable optical attenuator.

Description

Technical Field

[0001] This invention relates to the technical field of optical fiber transmission systems, specifically to an integrated adjustable optical attenuator and a method for manufacturing such a device. Background Technology

[0002] Fiber optic communication systems require numerous optical components, among which the Variable Optical Attenuator (VOA) is a common one. This device is primarily used to adjust the power of the optical signal transmitted in the fiber optic system, ensuring the optical receiver operates at its optimal receiving state. To detect the degree of attenuation achieved by the VOA, it is necessary to measure the power of the optical signal incident on the VOA and also the power of the optical signal emitted from it. Therefore, existing VOAs are typically used in conjunction with a Photodetector (PD) to achieve real-time monitoring of the optical power of the input and output signals, ensuring stable system operation.

[0003] Currently, most tunable optical attenuators with input and output optical power monitoring functions adopt a three-stage cascaded structure consisting of an input beam splitter, a tunable attenuator, and an output beam splitter. An input beam splitter is placed at the input of the optical signal to split the signal, for example, acquiring 1% to 5% of the signal for optical power detection. The remaining signal passes through the input beam splitter and continues transmission. The signal after passing through the tunable attenuator is then split and detected again by the output beam splitter. This type of tunable optical attenuator requires multiple fiber segments, and the fibers must be connected to the input, tunable, and output beam splitters using fusion splicing. In other words, several fiber segments fixed to the ends of the input, tunable, and output beam splitters are connected by fiber optic fusion splicing. However, this method has the following drawbacks: First, the entire optical device is bulky. Each unit cascaded requires a long optical fiber, which needs to be coiled to meet installation requirements. At the same time, the fusion splice points need to be equipped with fusion protection sleeves or coated with optical fibers, further occupying space. This results in a large overall device size, making it difficult to meet the urgent needs of miniaturization and high-density integration in current communication equipment.

[0004] Second, tunable optical attenuators have low reliability. Since the fusion splice of an optical fiber is the weakest link in the entire optical path, even after protection, it is still susceptible to external factors such as changes in ambient temperature and mechanical vibration, resulting in increased splice loss or even breakage, which seriously affects the long-term operational stability and service life of the device.

[0005] Third, the assembly of tunable optical attenuators is complex. The existing manufacturing process for tunable optical attenuators requires multiple steps, including fiber fusion splicing, splice protection, and fiber coiling and fixing. This assembly process is cumbersome and inefficient. Furthermore, each step relies on manual operation, and operational errors can easily lead to optical path misalignment and increased additional loss, thus affecting the consistency of optical device performance and yield.

[0006] Fourth, tunable optical attenuators are expensive. The equipment investment required for the fusion splicing process, the consumption of protective materials, the use of excess optical fiber, and the additional testing and debugging after assembly all significantly increase the material, time, and labor costs of the device, thus extending the production cycle of tunable optical attenuators.

[0007] In summary, existing adjustable optical attenuators with input and output optical power monitoring functions suffer from problems such as loose structure, poor reliability, cumbersome assembly, and high cost. There is an urgent need for a new type of adjustable optical attenuator that is compact, requires no welding, has high reliability, and is easy to assemble. Summary of the Invention

[0008] The primary objective of this invention is to provide an integrated adjustable optical attenuator that is compact, requires no welding, is highly reliable, and is easy to assemble.

[0009] A second objective of this invention is to provide a method for manufacturing the aforementioned integrated tunable optical attenuator.

[0010] To achieve the first objective of this invention, the integrated adjustable optical attenuator provided by this invention includes an input optical power detection unit having a first collimating lens, a first beam splitter, and a first photodetector chip arranged sequentially; and an output optical power detection unit having a second collimating lens, a second beam splitter, and a second photodetector chip arranged sequentially. The integrated adjustable optical attenuator further includes: an integrated optical fiber assembly having an input optical fiber head unit, an output optical fiber head unit, and an intermediate optical fiber head unit. The input optical fiber head unit has a first ceramic ferrule, the output optical fiber head unit has a second ceramic ferrule, and the intermediate optical fiber head unit has a third ceramic ferrule. The input optical fiber is fixed to the first ceramic ferrule, and the two ends of the first connecting optical fiber are fixed to the first and third ceramic ferrules respectively without fusion splicing. The two ends of the second connecting optical fiber are fixed to the second and third ceramic ferrules respectively without fusion splicing, and the output optical fiber is fixed to the second ceramic ferrule. The input optical fiber head unit is coupled to the input optical power detection unit, the output optical fiber head unit is coupled to the output optical power detection unit, and the intermediate optical fiber head unit is coupled to the adjustable optical attenuator unit.

[0011] As can be seen from the above scheme, the present invention uses an integrated optical fiber assembly. The input optical fiber head unit, output optical fiber head unit, and intermediate optical fiber head unit are pre-made in an integral manner to fix the input optical fiber, output optical fiber, first connecting optical fiber, and second connecting optical fiber. Moreover, each optical fiber is fixedly connected to the input optical fiber head unit, output optical fiber head unit, and intermediate optical fiber head unit in a non-fusion splice manner, which can avoid the generation of fusion splices, greatly improve the reliability of the integrated adjustable optical attenuator, and the packaging process is simple, which can reduce the production cost of the integrated adjustable optical attenuator.

[0012] In addition, since the first connecting optical fiber and the second connecting optical fiber have been pre-integrated into the integrated optical fiber assembly, the first connecting optical fiber and the second connecting optical fiber can be implemented using shorter optical fibers, which can significantly reduce the size of the integrated tunable optical attenuator and adapt to the needs of miniaturized and integrated communication equipment.

[0013] A preferred embodiment is that the input fiber optic head unit, the output fiber optic head unit, and the intermediate fiber optic head unit are manufactured using an integrated assembly and polishing process: the input fiber is inserted into the first ceramic ferrule, the output fiber is inserted into the second ceramic ferrule, the two ends of the first connecting fiber are respectively inserted into the first ceramic ferrule and the third ceramic ferrule, and the two ends of the second connecting fiber are respectively inserted into the second ceramic ferrule and the third ceramic ferrule, and then the end faces of the first ceramic ferrule, the second ceramic ferrule, and the third ceramic ferrule are polished.

[0014] Therefore, it is evident that by using an integrated assembly and polishing process to prefabricate integrated optical fiber components, the need for subsequent assembly of individual units can be eliminated, which simplifies the assembly difficulty of integrated tunable optical attenuators and improves their production efficiency.

[0015] A further design involves arranging the input fiber head unit, output fiber head unit, and intermediate fiber head unit in parallel with each other; both the first connecting fiber and the second connecting fiber are bend-insensitive fibers.

[0016] Therefore, using bend-insensitive optical fibers to fabricate the first and second connecting fibers can ensure the communication quality of the first and second connecting fibers, and can achieve small-scale bending, further reducing the size of the integrated tunable optical attenuator.

[0017] A further proposed solution is that the output end of the input fiber optic head unit is directly opposite the input end of the input optical power detection unit, and the input fiber optic head unit and the input optical power detection unit are fixed together with a curing adhesive; the output end of the output fiber optic head unit is directly opposite the input end of the output optical power detection unit, and the output fiber optic head unit and the output optical power detection unit are fixed together with a curing adhesive; the output end of the intermediate fiber optic head unit is directly opposite the input end of the adjustable optical attenuation unit, and the intermediate fiber optic head unit and the adjustable optical attenuation unit are fixed together with a curing adhesive.

[0018] Therefore, it can be seen that using curing adhesive to connect multiple units such as the input fiber optic head unit and the input optical power detection unit makes the connection and fixing operation between the input fiber optic head unit and the input optical power detection unit very simple. Moreover, curing adhesive is widely used in the assembly process of passive optical devices and has good performance stability and reliability.

[0019] A further proposed solution is to encapsulate the input fiber optic head unit and the input optical power detection unit within a first housing; the output fiber optic head unit and the output optical power detection unit within a second housing; and the intermediate fiber optic head unit and the adjustable optical attenuation unit within a third housing.

[0020] It is evident that by setting up three housings, and encapsulating the input fiber head unit and the input optical power detection unit in three separate housings, it is beneficial to achieve miniaturization of the integrated tunable optical attenuator.

[0021] A further option is that the adjustable light attenuation unit includes a microelectromechanical device (MEMS) and a third collimating lens, with the third collimating lens located on one side of the MEMS.

[0022] A further approach involves encapsulating the input optical power detection unit, output optical power detection unit, adjustable optical attenuation unit, and integrated optical fiber assembly within a metal housing, with only the input end of the input optical fiber and the output end of the output optical fiber exposed outside the metal housing.

[0023] Therefore, by setting up a small metal housing, the input optical power detection unit, output optical power detection unit, adjustable optical attenuation unit and integrated optical fiber assembly are all encapsulated in the metal housing, with only the input end of the input optical fiber and the output end of the output optical fiber exposed outside the metal housing. This can improve the sealing performance of the integrated adjustable optical attenuator and also help ensure the stability of each unit.

[0024] To achieve the second objective mentioned above, the method for manufacturing an integrated tunable optical attenuator provided by the present invention includes: manufacturing an integrated optical fiber assembly; and using an integrated assembly and polishing process to manufacture an input optical fiber head unit, an output optical fiber head unit, and an intermediate optical fiber head unit. The input optical fiber head unit has a first ceramic ferrule, the output optical fiber head unit has a second ceramic ferrule, and the intermediate optical fiber head unit has a third ceramic ferrule, such that the input optical fiber is fixed to the first ceramic ferrule, the two ends of a first connecting optical fiber are fixed to the first ceramic ferrule and the third ceramic ferrule respectively without fusion splicing, the two ends of a second connecting optical fiber are fixed to the second ceramic ferrule and the third ceramic ferrule respectively without fusion splicing, and the output optical fiber is fixed... The second ceramic ferrule; the integrated assembly and polishing process for fabricating the input fiber head unit, output fiber head unit, and intermediate fiber head unit includes: inserting the input fiber into the first ceramic ferrule, inserting the output fiber into the second ceramic ferrule, inserting both ends of the first connecting fiber into the first ceramic ferrule and the third ceramic ferrule respectively, inserting both ends of the second connecting fiber into the second ceramic ferrule and the third ceramic ferrule respectively, and then polishing the end faces of the first, second, and third ceramic ferrules; coupling the input fiber head unit to the input optical power detection unit, coupling the output fiber head unit to the output optical power detection unit, and coupling the intermediate fiber head unit to the adjustable optical attenuation unit.

[0025] As can be seen from the above scheme, the present invention manufactures an integrated tunable optical attenuator by first fabricating an integrated optical fiber assembly through a one-piece assembly and polishing process. This process fixes the input optical fiber, output optical fiber, and first and second connecting optical fibers. In this way, each optical fiber is fixedly connected to the input fiber head unit, output fiber head unit, and intermediate fiber head unit without fusion splices, thus avoiding the generation of fusion splices and significantly improving the reliability of the integrated tunable optical attenuator. Furthermore, the packaging process is simple, reducing the production cost of the integrated tunable optical attenuator. In addition, since the first and second connecting optical fibers of the present invention are pre-integrated into the integrated optical fiber assembly, shorter optical fibers can be used for the first and second connecting optical fibers, significantly reducing the size of the integrated tunable optical attenuator.

[0026] A preferred embodiment is to couple the input fiber optic head unit with the input optical power detection unit and encapsulate them in a first housing; couple the output fiber optic head unit with the output optical power detection unit and encapsulate them in a second housing; and couple the intermediate fiber optic head unit with the adjustable optical attenuation unit and encapsulate them in a third housing.

[0027] A further approach is to encapsulate the input optical power detection unit, the output optical power detection unit, the adjustable optical attenuation unit, and the integrated optical fiber assembly within a metal housing, with only the input end of the input optical fiber and the output end of the output optical fiber exposed outside the metal housing. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the first embodiment of the integrated adjustable optical attenuator of the present invention.

[0029] Figure 2 This is a schematic diagram of the integrated optical fiber assembly of the first embodiment of the integrated adjustable optical attenuator of the present invention.

[0030] Figure 3 This is the optical path diagram of the first embodiment of the integrated adjustable optical attenuator of the present invention.

[0031] Figure 4 This is a schematic diagram of the packaged structure of the first embodiment of the integrated adjustable optical attenuator of the present invention.

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0033] The integrated adjustable optical attenuator of this invention can adjust the optical power of the input optical signal and can also detect the optical power of the input and output optical signals. The integrated adjustable optical attenuator of this invention is manufactured using a fusion-free method, completely eliminating fusion points. This avoids the defects of unstable quality and large size caused by fusion operations, thus facilitating the miniaturization of optical fiber communication systems.

[0034] First embodiment: The integrated adjustable optical attenuator in this embodiment is an integrated adjustable optical attenuator that monitors the optical power of both the input and output optical signals. See [link to documentation]. Figure 1 The integrated adjustable optical attenuator includes an integrated optical fiber assembly 10, which has an input optical fiber head unit 11, an output optical fiber head unit 12, and an intermediate optical fiber head unit 13, arranged in parallel with each other. The input optical fiber head unit 11 has a first ceramic ferrule, the output optical fiber head unit 12 has a second ceramic ferrule, and the intermediate optical fiber head unit 13 has a third ceramic ferrule. In this embodiment, the first, second, and third ceramic ferrules are all dual-hole ceramic ferrules, each with two insertion holes, each hole capable of inserting the end of an optical fiber.

[0035] See Figure 2One end of the input optical fiber 15 is inserted into a socket of the first ceramic ferrule, while the two ends of the first connecting optical fiber 16 are fixed to the first and third ceramic ferrules respectively. In this embodiment, both ends of the first connecting optical fiber 16 are fixed to the first and third ceramic ferrules without fusion splicing. Similarly, the two ends of the second connecting optical fiber 17 are also fixed to the second and third ceramic ferrules without fusion splicing, and the output optical fiber 18 is also fixed to the second ceramic ferrule. Furthermore, the input optical fiber head unit 11, the output optical fiber head unit 12, and the intermediate optical fiber head unit 13 are manufactured using an integrated assembly and polishing process. Specifically, when manufacturing the input optical fiber head unit 11, the output optical fiber head unit 12, and the intermediate optical fiber head unit 13, the input optical fiber 15, the first connecting optical fiber 16, the second connecting optical fiber 17, and the output optical fiber 18 are first inserted into the sockets of the corresponding ceramic ferrules, and then the ceramic ferrules and optical fibers are fixed using an integrated assembly and polishing process, thereby forming an integrated optical fiber assembly 10.

[0036] As can be seen, since the ends of each optical fiber are fixed in the socket of the ceramic ferrule, and then the ends of each optical fiber are fixed to the ceramic ferrule with curing adhesive, this method can ensure the fixed connection between each optical fiber and each ceramic ferrule, and does not require the use of fusion splicing process, thus not forming fusion points. Therefore, the integrated optical fiber assembly 10 does not have any fusion points, which can improve the stability of the integrated optical fiber assembly 10.

[0037] In this embodiment, the lengths of the first connecting fiber 16 and the second connecting fiber 17 are both 25 mm or more, thereby ensuring that the integrated adjustable optical attenuator can be integrated into a metal housing with a width of 20 mm. Furthermore, both the first connecting fiber 16 and the second connecting fiber 17 are bend-insensitive fibers, and their bending radii meet preset requirements. For example, for fiber of model G657.A2, the minimum bending radius is not less than 7.5 mm.

[0038] The integrated adjustable optical attenuator also includes an input optical power detection unit 20, an output optical power detection unit 30, and an adjustable optical attenuation unit. The input optical power detection unit 20 comprises a first collimating lens 21, a first beam splitter 22, and a first photodetector chip 23 arranged sequentially. The first collimating lens 21 is closest to the input fiber optic head unit 11, and the first beam splitter 22 is located between the first collimating lens 21 and the first photodetector chip 23. The output optical power detection unit 30 comprises a second collimating lens 31, a second beam splitter 32, and a second photodetector chip 33 arranged sequentially. The second collimating lens 31 is closest to the output fiber optic head unit 12, and the second beam splitter 32 is located between the second collimating lens 31 and the second photodetector chip 33.

[0039] The adjustable optical attenuation unit 40 includes a microelectromechanical device (MEMS) 42 and a third collimating lens 41. The third collimating lens 41 is located on one side of the MEMS 42, specifically at the end near the intermediate fiber optic head unit 13. The MEMS 42 is a device with an adjustable tilt angle. By adjusting the tilt angle of the MEMS 42, the coupling efficiency of the reflected light signal is changed, thereby adjusting the attenuation of the optical power of the light signal. Furthermore, the adjustable optical attenuation unit 40 has an attenuation adjustment range of 0 to 30 dB, an adjustment accuracy of 0.1 dB, and a fast response speed.

[0040] See Figure 3 The input fiber optic head unit 11 and the input optical power detection unit 20 are positioned opposite each other and coupled. Specifically, the input end of the input fiber optic head unit 11 is directly opposite the input end of the input optical power detection unit 20. Preferably, the outer diameter of the input fiber optic head unit 11 is equal to the outer diameter of the input optical power detection unit 20. When fixing the input fiber optic head unit 11 and the input optical power detection unit 20, a curing adhesive is filled between them to fix them in place. Finally, a first housing 51 is fitted over the input fiber optic head unit 11 and the input optical power detection unit 20. Figure 4 As shown, the first housing 51 is a cylindrical housing, thereby encapsulating the input fiber optic head unit 11 and the input optical power detection unit 20.

[0041] Similarly, the output fiber optic head unit 12 and the output optical power detection unit 30 are positioned opposite each other and coupled. Specifically, the input end of the output fiber optic head unit 12 is directly opposite the input end of the output fiber optic head unit 30. Preferably, the outer diameter of the output fiber optic head unit 12 is equal to the outer diameter of the output optical power detection unit 30. When fixing the output fiber optic head unit 12 and the output optical power detection unit 30, a curing adhesive is filled between them to fix them in place. Finally, a second housing 52 is fitted over the output fiber optic head unit 12 and the output optical power detection unit 30. Figure 4 As shown, the second housing 52 is a cylindrical housing, thereby encapsulating the output fiber optic head unit 12 and the output optical power detection unit 30.

[0042] The intermediate fiber optic head unit 13 and the adjustable optical attenuation unit 40 are positioned opposite each other and coupled. Specifically, the output end of the intermediate fiber optic head unit 13 is directly opposite the input end of the adjustable optical attenuation unit 40. Preferably, the outer diameter of the intermediate fiber optic head unit 13 is equal to the outer diameter of the adjustable optical attenuation unit 40. When fixing the intermediate fiber optic head unit 13 and the adjustable optical attenuation unit 40, a curing adhesive is filled between the intermediate fiber optic head unit 13 and the adjustable optical attenuation unit 40. The curing adhesive is used to fix the intermediate fiber optic head unit 13 and the adjustable optical attenuation unit 40. Finally, a third housing 53, which is a cylindrical housing, is fitted over the intermediate fiber optic head unit 13 and the adjustable optical attenuation unit 40, thereby achieving the encapsulation of the intermediate fiber optic head unit 13 and the adjustable optical attenuation unit 40.

[0043] Furthermore, the input optical power detection unit 20, the output optical power detection unit 30, the adjustable optical attenuation unit 40, and the integrated fiber optic assembly 10 are encapsulated within a square metal housing 50, which measures 40 mm × 20 mm × 5 mm. More specifically, the metal housing 50 is made of aluminum alloy. Figure 4 As can be seen, the first connecting fiber 16 and the second connecting fiber 17 are both encapsulated within the metal housing 50, with only the input end of the input fiber 15 and the output end of the output fiber 18 exposed outside the metal housing 50. This design enables the integrated adjustable optical attenuator to possess excellent anti-interference and heat dissipation performance.

[0044] See Figure 3 The input optical signal enters through the input optical fiber 15, then passes through the first collimating lens 21 of the input optical power detection unit 20, and then through the first beam splitter 22. A small portion of the optical signal passes through the first beam splitter 22 and passes through the first photoelectric detection chip 23 for optical power detection, for example, 1% to 5% of the optical signal is used for optical power detection. Most of the optical signal is reflected to the first connecting optical fiber 16 and passes through the third collimating lens 41. After being reflected by the microelectromechanical device 42, it passes through the second connecting optical fiber 17 and then through the second collimating lens 31 of the output optical power detection unit 30. When passing through the second beam splitter 32, a small portion of the optical signal passes through the second beam splitter 32 and passes through the second photoelectric detection chip 33 for optical power detection. Most of the optical signal is reflected to the output optical fiber 18.

[0045] When fabricating the integrated tunable optical attenuator of this embodiment, the integrated optical fiber assembly 10 is first fabricated. Specifically, the input optical fiber head unit 11, the output optical fiber head unit 12, and the intermediate optical fiber head unit 13 are fabricated using an integrated assembly and polishing process. First, a first ceramic ferrule, a second ceramic ferrule, and a third ceramic ferrule are prepared. One end of the input optical fiber 15 is inserted into the first ceramic ferrule. Both ends of the first connecting optical fiber 16 are inserted into the first and third ceramic ferrules, respectively. The second connecting optical fiber 17 is inserted into the second and third ceramic ferrules, respectively. The output optical fiber 18 is inserted into the third ceramic ferrule. Finally, the three ceramic ferrules are encapsulated using an integrated assembly and polishing process, thereby fixing each optical fiber to each ceramic ferrule.

[0046] Specifically, the optical fibers are first inserted. One end of the input optical fiber 15 is inserted and fixed into one of the holes of the first ceramic ferrule, completing the single assembly of the input optical fiber head unit 11. Then, the first end of the first connecting optical fiber 16 is inserted into another hole of the first ceramic ferrule, and the other end is inserted into the matching hole of the third ceramic ferrule, achieving a non-fusion-splitter connection between the first and third ceramic ferrules. Next, the first end of the second connecting optical fiber 17 is inserted into the hole of the third ceramic ferrule, and the second end is inserted into the corresponding hole of the second ceramic ferrule, achieving a non-fusion-splitter connection between the third and second ceramic ferrules. Finally, one end of the output optical fiber 18 is inserted and fixed into the corresponding hole of the second ceramic ferrule, completing the integrated fiber optic cable assembly and obtaining a three-head pigtail semi-finished product without any fusion points.

[0047] Next, the fiber optic heads are polished. Since the polishing end faces of the first and second ceramic ferrules face opposite directions when the first connecting fiber 16 and the second connecting fiber 17 are not bent, the polishing operation must be performed without bending the first connecting fiber 16 and the second connecting fiber 17. First, a uniform forward polishing is performed, where the assembled first and second ceramic ferrules are clamped together in the polishing fixture, and the fiber end faces of the first and second ceramic ferrules are precision polished as a single unit. Then, a second clamping and repositioning process is performed; that is, after completing the forward polishing, the processed first and second ceramic ferrules are removed, and the third ceramic ferrule is clamped and fixed in the reverse direction. Finally, an independent reverse polishing is performed, where the end face of the clamped third ceramic ferrule is independently precision polished. This completes the polishing of all end faces of the integrated fiber optic assembly.

[0048] Of course, if the first and second connecting optical fibers are bent during polishing so that the end faces of the first, second, and third ceramic ferrules all face the same direction, the first, second, and third ceramic ferrules can also be clamped and fixed together on the polishing fixture, and the end faces of the first, second, and third ceramic ferrules can be polished at the same time, thereby improving polishing efficiency.

[0049] Thus, the entire manufacturing process does not require fusion splicing, and therefore, the integrated optical fiber assembly 10 has no fusion points. During the manufacturing process, the bending radius of the first connecting optical fiber 16 and the second connecting optical fiber 17 is controlled at 7.5 mm to meet the bending requirements.

[0050] Then, the input fiber optic head unit 11 is coupled to the input optical power detection unit 20. Specifically, the input fiber optic head unit 11 and the input optical power detection unit 20 are fixed and encapsulated in the first housing using a curing adhesive. The output fiber optic head unit 12 is then coupled to the output optical power detection unit 30, and the output fiber optic head unit 12 and the output optical power detection unit 30 are fixed and encapsulated in the second housing using a curing adhesive. Finally, the intermediate fiber optic head unit 13 is coupled to the adjustable optical attenuation unit 40, and the intermediate fiber optic head unit 13 and the adjustable optical attenuation unit 40 are fixed and encapsulated in the third housing using a curing adhesive. Preferably, when coupling the input fiber optic head unit 11 to the input optical power detection unit 20, and when coupling the output fiber optic head unit 12 to the output optical power detection unit 30, the coupling position needs to be adjusted to ensure the detection accuracy of the optical signal. When coupling the intermediate fiber optic head unit 13 to the adjustable optical attenuation unit 40, planar coupling adjustment is required to ensure stable attenuation adjustment performance.

[0051] Finally, the input optical power detection unit 20, the output optical power detection unit 30, the adjustable optical attenuation unit 40, and the integrated optical fiber assembly 10 are encapsulated in a square metal housing 50. The first connecting optical fiber 16 and the second connecting optical fiber 17 are also encapsulated in the metal housing 50. Only the input end of the input optical fiber 15 and the output end of the output optical fiber 18 are exposed outside the metal housing 50 to realize the input and output of external optical signals.

[0052] Compared to traditional tunable optical attenuators, the integrated tunable optical attenuator in this embodiment can reduce the size by more than 60%. Furthermore, since there are no fusion splices, the assembly process is simple and the assembly efficiency is high. It can improve the assembly efficiency by 50% and reduce the production cost by 30% compared to traditional tunable optical attenuators. It can be widely used in miniaturized optical fiber communication equipment, optical modules and other scenarios.

[0053] Second embodiment: The integrated adjustable optical attenuator of this embodiment has an integrated optical fiber assembly, an input optical power detection unit, an output optical power detection unit, and an adjustable optical attenuation unit. The integrated optical fiber assembly has an input optical fiber head unit, an output optical fiber head unit, and an intermediate optical fiber head unit. The integrated optical fiber assembly is manufactured in a fusion-free manner.

[0054] Unlike the first embodiment, each ceramic ferrule in this embodiment is made of quartz glass, the length of the first connecting optical fiber and the second connecting optical fiber is 55 mm, the adjustable light attenuation unit is a liquid crystal adjustable light attenuation unit, and the size of the metal housing is 38 mm × 15 mm × 5 mm. The rest of the structure is the same as the first embodiment.

[0055] This embodiment uses a liquid crystal adjustable light attenuation unit with lower power consumption, which is suitable for small optical communication equipment with high power consumption requirements. It also has the advantages of no fusion splicing, high reliability and compact integration.

[0056] As can be seen, the integrated optical fiber assembly of the present invention has three dual-ended ceramic ferrules. These three ferrules are cascaded to form the integrated optical fiber assembly. Furthermore, the first and second connecting optical fibers are very small in size and are all manufactured using a non-fusion splicing process, which significantly reduces the size of the integrated adjustable optical attenuator and adapts to the needs of miniaturized and integrated communication equipment. Moreover, because the dual-ended ceramic ferrules employ a high-precision positioning structure, the optical fiber arrangement is accurate, the optical path loss is low, and the integration of each component is high, avoiding performance fluctuations caused by manual assembly errors and ensuring the consistency of the integrated adjustable optical attenuator's performance.

[0057] In addition, since all optical fibers are connected without fusion splicing and the optical path is continuously prefabricated, the weak link of the fusion splice is eliminated, reducing the impact of environmental factors on the performance of the integrated tunable optical attenuator and improving the long-term stability and service life of the integrated tunable optical attenuator.

[0058] In addition, the integrated adjustable optical attenuator can simultaneously realize real-time monitoring of the optical power of the input optical signal and the optical signal attenuation adjustment, meeting the core requirements of optical fiber communication systems. Moreover, the integrated design makes the integrated adjustable optical attenuator more adaptable.

[0059] Finally, it should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An integrated tunable attenuator, including: The input optical power detection unit comprises a first collimating lens, a first beam splitter, and a first photoelectric detection chip arranged sequentially. The output optical power detection unit has a second collimating lens, a second beam splitter, and a second photoelectric detection chip arranged in sequence. The integrated tunable attenuator is characterized by further comprising: An integrated optical fiber assembly includes an input optical fiber head unit, an output optical fiber head unit, and an intermediate optical fiber head unit. The input optical fiber head unit has a first ceramic ferrule, the output optical fiber head unit has a second ceramic ferrule, and the intermediate optical fiber head unit has a third ceramic ferrule. The input optical fiber is fixed to the first ceramic ferrule, and the two ends of a first connecting optical fiber are fixed to the first ceramic ferrule and the third ceramic ferrule, respectively, without fusion splicing. The two ends of a second connecting optical fiber are fixed to the second ceramic ferrule and the third ceramic ferrule, respectively, without fusion splicing. The output optical fiber is fixed to the second ceramic ferrule. The input fiber optic head unit is coupled to the input optical power detection unit, the output fiber optic head unit is coupled to the output optical power detection unit, and the intermediate fiber optic head unit is coupled to the adjustable optical attenuation unit. The input fiber optic head unit, the output fiber optic head unit, and the intermediate fiber optic head unit are manufactured using an integrated assembly and polishing process: the input fiber is inserted into the first ceramic ferrule, the output fiber is inserted into the second ceramic ferrule, both ends of the first connecting fiber are respectively inserted into the first ceramic ferrule and the third ceramic ferrule, and both ends of the second connecting fiber are respectively inserted into the second ceramic ferrule and the third ceramic ferrule, and then the end faces of the first ceramic ferrule, the second ceramic ferrule, and the third ceramic ferrule are polished.

2. The integrated tunable optical attenuator according to claim 1, characterized in that: The input fiber optic head unit, the output fiber optic head unit, and the intermediate fiber optic head unit are arranged in parallel to each other; Both the first connecting optical fiber and the second connecting optical fiber are bend-insensitive optical fibers.

3. The integrated tunable optical attenuator according to claim 1 or 2, characterized in that: The output end of the input fiber optic head unit is directly opposite the input end of the input optical power detection unit, and the input fiber optic head unit and the input optical power detection unit are fixed together by a curing adhesive. The output end of the output fiber optic head unit is directly opposite the input end of the output optical power detection unit, and the output fiber optic head unit and the output optical power detection unit are fixed together by a curing adhesive. The output end of the intermediate fiber optic head unit is directly opposite the input end of the adjustable light attenuation unit, and the intermediate fiber optic head unit and the adjustable light attenuation unit are fixed together by a curing adhesive.

4. The integrated tunable optical attenuator according to claim 3, characterized in that: The input fiber optic head unit and the input optical power detection unit are encapsulated within the first housing; The output fiber head unit and the output optical power detection unit are encapsulated in the second housing; The intermediate fiber head unit and the adjustable optical attenuation unit are encapsulated in a third housing.

5. The integrated tunable optical attenuator according to claim 1 or 2, characterized in that: The adjustable light attenuation unit includes a microelectromechanical device (MEMS) and a third collimating lens, the third collimating lens being located on one side of the MEMS.

6. The integrated tunable optical attenuator according to claim 1 or 2, characterized in that: The input optical power detection unit, the output optical power detection unit, the adjustable optical attenuation unit, and the integrated optical fiber assembly are encapsulated in a metal housing, with only the input end of the input optical fiber and the output end of the output optical fiber exposed outside the metal housing.

7. A method for manufacturing an integrated adjustable optical attenuator, characterized in that, include: An integrated optical fiber assembly is fabricated using an integrated assembly and polishing process to create an input optical fiber head unit, an output optical fiber head unit, and an intermediate optical fiber head unit. The input optical fiber head unit has a first ceramic ferrule, the output optical fiber head unit has a second ceramic ferrule, and the intermediate optical fiber head unit has a third ceramic ferrule. The input optical fiber is fixed to the first ceramic ferrule, and the two ends of a first connecting optical fiber are fixed to the first and third ceramic ferrules respectively without fusion splicing. The two ends of a second connecting optical fiber are also fixed to the second and third ceramic ferrules respectively without fusion splicing. The output optical fiber is fixed to the second ceramic ferrule. The process of fabricating the input fiber optic head unit, output fiber optic head unit, and intermediate fiber optic head unit using an integrated assembly and polishing process includes: inserting the input fiber into the first ceramic ferrule, inserting the output fiber into the second ceramic ferrule, inserting both ends of the first connecting fiber into the first ceramic ferrule and the third ceramic ferrule respectively, inserting both ends of the second connecting fiber into the second ceramic ferrule and the third ceramic ferrule respectively, and then polishing the end faces of the first ceramic ferrule, the second ceramic ferrule, and the third ceramic ferrule. The input fiber head unit is coupled to the input optical power detection unit, the output fiber head unit is coupled to the output optical power detection unit, and the intermediate fiber head unit is coupled to the adjustable optical attenuation unit.

8. The method for manufacturing an integrated tunable optical attenuator according to claim 7, characterized in that: The input fiber head unit is coupled to the input optical power detection unit and then encapsulated in the first housing; The output fiber head unit and the output optical power detection unit are coupled together and then encapsulated in the second housing; The intermediate fiber head unit is coupled to the tunable optical attenuation unit and then encapsulated in the third housing.

9. The method for manufacturing an integrated tunable optical attenuator according to claim 7 or 8, characterized in that, Also includes: The input optical power detection unit, the output optical power detection unit, the adjustable optical attenuation unit, and the integrated optical fiber assembly are encapsulated in a metal housing, with only the input end of the input optical fiber and the output end of the output optical fiber exposed outside the metal housing.

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