Optical filter, single-fiber bidirectional optical device and packaging method thereof

Abstract

The invention relates to the technical field of optical communication, in particular to an optical filter, a single-fiber bidirectional optical device and a packaging method of the single-fiber bidirectional optical device. According to the invention, the first filter and the second filter are integrated on the prism, and the current wavelength is calibrated to be within the preset passband range by controlling the coupling position and angle of the prism. On one hand, the first filter and the second filter are mounted on the same prism, so that the relative mounting precision between the filters can be better ensured; the integrated optical filter can finely adjust the overall optical path in the device by adjusting the overall position of the integrated optical filter, so that the error-tolerant rate is higher; and on the other hand, by accurately controlling the assembling angle of the prism, the packaging yield of the single-fiber bidirectional optical device is improved, the problem of poor actual light splitting effect caused by inaccurate assembling angle can be effectively avoided, and the performance and the stability of the device are improved.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and in particular to an optical filter, a single-fiber bidirectional optical device, and a packaging method thereof. Background Technology

[0002] In the field of optoelectronic devices, wavelength division multiplexing (WDM) is an important technology that can transmit multiple optical signals of different wavelengths in a single optical fiber, thereby improving the transmission capacity and efficiency of the optical fiber.

[0003] In single-fiber bidirectional optical devices, filters are typically used to separate and combine optical signals of different wavelengths. As system capacity increases, the number of channels grows, channel spacing becomes denser, and the transition band between adjacent channels narrows. In 5G applications, wavelength spacing has gradually decreased from 60nm to 10nm, and the transition band has decreased from 40nm to about 5nm. Especially in LWDM wavelength applications, the protocol requires a wavelength spacing of only 5nm and a transition band of only 2.5nm. At this point, a single 45-degree filter can no longer separate the two wavelengths.

[0004] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field. Summary of the Invention

[0005] The technical problem this invention aims to solve is how to address the issue that in narrowband applications, a conventional single 45-degree filter cannot meet the device's specifications and cannot guarantee the device's passband range.

[0006] The present invention adopts the following technical solution: In a first aspect, an optical filter is provided, disposed in a single-fiber bidirectional optical device, the optical filter 1 including: a first filter 10, a second filter 12 and a prism 13; The first filter 10 and the second filter 12 are respectively disposed on the prism 13 at a preset angle; By adjusting the mounting position and angle of the prism 13 in the single-fiber bidirectional optical device, the passband range of the single-fiber bidirectional optical device can be guaranteed.

[0007] In a second aspect, a single-fiber bidirectional optical device is provided, including a circular-square tube 2, an optical filter 1 as described in the first aspect, a transmitting optical device 3, and a receiving optical device 4. The optical filter 1 is disposed inside the circular tube 2, and the transmitting optical device 3 and the receiving optical device 4 are disposed on the circular tube 2 and are respectively coupled to the optical filter 1. The transmitting optical device 3 is used to emit a first wavelength optical signal, which is coupled to the output optical fiber via the optical filter 1. The receiving optical device 4 is used to receive the second wavelength optical signal obtained after being divided by the optical filter 1; The passband range of the single-fiber bidirectional optical device is ensured by adjusting the installation position and angle of the optical filter 1 inside the circular tube 2.

[0008] Thirdly, a packaging method for a single-fiber bidirectional optical device is provided, for packaging the single-fiber bidirectional optical device as described in the second aspect, comprising: Assemble the optical filter 1; The optical filter 1 is disposed inside the round-square tube 2; The transmitting optical device 3 is disposed on the circular-square tube 2, and the receiving optical device 4 is disposed on the circular-square tube 2 to obtain the single-fiber bidirectional optical device.

[0009] Preferably, assembling the optical filter 1 specifically includes: The prism 13 is disposed on the substrate 14; The first filter 10 and the second filter 12 are respectively set on the prism 13 at a preset angle to obtain the optical filter 1.

[0010] Preferably, the step of placing the optical filter 1 inside the circular-square tube 2 specifically includes: UV-curable adhesive is applied to the square groove inside the round-square tube 2, and the substrate 14 is placed in the square groove and pressed flat so that the substrate 14 comes into contact with the UV-curable adhesive. The collimation adapter 5 is inserted into the transmitting port of the round-square tube 2, and an optical fiber patch cord is connected to the collimation adapter 5 to provide the incident light signal; an optical power meter is set at the receiving port of the round-square tube 2 to monitor the output light power. The position and angle of the optical filter 1 are adjusted by the fine-tuning device so that the outgoing light power Pout detected by the optical power meter is equal to the incident light power Pin of the incident light signal. Adjust the wavelength of the incident light signal to the passband edge wavelength required by the protocol, and confirm that the output light power Pout = the incident light power Pin to verify the passband range; The UV-curing adhesive is pre-cured by irradiation with a UV lamp and then heat-cured by baking at a high temperature to place the optical filter 1 inside the round-square tube 2.

[0011] Preferably, the passband edge wavelength range is 1303.6nm-1305.6nm, or 1308.1nm-1310.1nm.

[0012] Preferably, the single-fiber bidirectional optical device further includes a collimation adapter 5, and the transmitting optical device 3 includes an emitting laser 31 and an adjustment ring 32; The step of mounting the transmitting optical device 3 on the circular-square tube 2 specifically includes: The collimation adapter 5, the round-square tube 2, the adjusting ring 32, and the emitting laser 31 are sequentially clamped onto the coupling welding equipment; wherein, the collimation adapter 5 is inserted into the emission port on the round-square tube 2 and rotates only around the axis, the round-square tube 2 is adjustable only in the Z-axis position, the emitting laser 31 is adjustable in the X-axis and Y-axis directions, and the adjusting ring 32 is sleeved on the bottom of the round-square tube 2 and contacts the emitting laser 31; Power on the emitting laser 31 and adjust the X-axis and Y-axis positions of the emitting laser 31 in sequence to find the optical signal; determine the focal length by adjusting the Z-axis position of the round-square tube 2, rotate the collimating adapter 5 to find the high point direction with the maximum output light power, and pre-fix the collimating adapter 5 in the high point direction to the round-square tube 2 by laser welding; The X-axis and Y-axis positions of the emitting laser 31 and the Z-axis position of the circular-square tube 2 are adjusted respectively to maximize the emitted light power. The adjusting ring 32 is welded to the circular-square tube 2 and the emitting laser 31 by laser welding to complete the coupling of the emitting optical device 3.

[0013] Preferably, the welding method for pre-fixing the collimator 5 to the round-square tube 2 is lap welding, and the welding point is located at the mating gap between the collimator 5 and the round-square tube 2.

[0014] Preferably, the receiver tube 40, the receiver lens 41, and the receiver detector 42 are included. The step of mounting the receiving optical device 4 on the circular-square tube 2 specifically includes: The receiving lens 41 is attached to the receiving tube 40; The receiving tube 40 is welded and fixed to the receiving port of the round-square tube 2 using laser welding. The receiver detector 42 is coupled and inserted into the receiver tube 40, and the position of the receiver detector 42 is adjusted to maximize the responsivity. The receiver detector 42 is then fixed in the receiver tube 40 assembly by UV pre-curing and black glue secondary curing.

[0015] Preferably, the UV adhesive and black adhesive are applied at the gap between the receiver detector 42 and the receiver tube 40.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention integrates a first filter 10 and a second filter 12 onto a prism 13, and calibrates the current wavelength to a preset passband range by controlling the coupling position and angle of the prism 13. On one hand, mounting the first filter 10 and the second filter 12 onto the same prism 13 better ensures the relative mounting accuracy between the filters; the integrated optical filter 1 can fine-tune the overall optical path within the device by adjusting its overall position, resulting in higher fault tolerance. On the other hand, by precisely controlling the assembly angle of the prism 13, the packaging yield of the single-fiber bidirectional optical device is improved, effectively avoiding the problem of poor actual beam splitting effect caused by inaccurate assembly angles, thus improving the device's performance and stability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of an optical filter provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the optical path structure of an optical filter provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a single-fiber bidirectional optical device provided in an embodiment of the present invention; Figure 4 This is a schematic flowchart of a packaging method for a single-fiber bidirectional optical device provided in an embodiment of the present invention; Figure 5 This is a schematic flowchart of an optical filter installation method provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a light emitting device provided in an embodiment of the present invention; Figure 7 This is a schematic flowchart of a coupling method for an optical device at the transmitting end provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of another single-fiber bidirectional optical device provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of a receiving optical device provided in an embodiment of the present invention.

[0019] In all the accompanying drawings, the same reference numerals denote the same structure, wherein: Optical filter 1, first filter 10, second filter 12, prism 13, substrate 14, round and square tube 2, emitting optical device 3, emitting laser 31, adjustment ring 32, receiving optical device 4, receiving tube 40, receiving lens 41, receiving detector 42, collimation adapter 5. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0021] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as openly inclusive, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples; that is, although they may be incorporated into embodiments or examples using the above terms for reasons such as order and position, it does not limit them to be incorporated in combination by a single embodiment or example.

[0022] In the description of this invention, 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, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, for example, the description may use the prefix "A" or "B" to describe the same type of nouns as two independent entities. In this case, the corresponding features defined with "A" and "B" are used only to distinguish between similar entities and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0023] In describing some embodiments, the terms "coupled," "coupled," and "connected," and their derivative expressions, may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact with each other. Similarly, the term "coupled" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact. However, the terms "connected" or "coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other, such as "optical coupling," "wireless connection," etc. The embodiments disclosed herein are not necessarily limited to the scope of this invention.

[0024] Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] Example 1: To address the problems of existing technologies, this embodiment proposes an optical filter. In one embodiment, such as... Figure 1 As shown, the optical filter 1, disposed in a single-fiber bidirectional optical device, includes a first filter 10, a second filter 12, and a prism 13; the first filter 10 and the second filter 12 are respectively disposed on the prism 13 at a preset angle; by adjusting the mounting position and mounting angle of the prism 13 in the single-fiber bidirectional optical device, the passband range of the single-fiber bidirectional optical device is ensured.

[0026] Among them, reference Figure 1 The optical filter 1 further includes a substrate 14. After the first filter 10 and the second filter 12 are disposed on the prism 13, the prism 13 is then fixed on the substrate 14. The optical filter 1 is fixed by fixing the substrate 14 at a preset mounting position in the single-fiber bidirectional optical device.

[0027] In one embodiment, the prism 13 serves as an optical substrate, precision-machined to have specific angles and dimensions. Its main function is to provide an ultra-high precision mounting reference for the filter and guide the optical path to the correct direction. Its specific shape is set according to the actual optical path design and is not specifically limited in this embodiment.

[0028] The first filter 10 and the second filter 12 are the core optical thin-film elements that realize the wavelength separation function. They are fixed at a preset angle on a specific surface of the prism 13. The preset angle is the optimal angle calculated based on the optical path design and the target wavelength, and is not specifically limited in this embodiment.

[0029] In one embodiment, such as Figure 2The diagram illustrates the transmission path of an optical signal within the optical filter 1. The optical signal emitted by the transmitting optical device 3 is coupled into the prism 13 via the first filter 10, then refracted by the prism 13 and emitted from its exit surface. Externally received optical signals enter through the receiving surface (which is also the exit surface, corresponding to the same optical fiber) of the prism 13, are refracted by the prism 13, and exit through the second filter 12 to the receiving optical device 4. The first filter 10 and the second filter 12 selectively filter out wavelengths of the optical signal, allowing only specific wavelengths to pass through, thus achieving the effect of optical filtering.

[0030] In this embodiment, the first filter 10 and the second filter 12 are integrated with high precision onto an independent prism 13, which solves the problem of the accuracy of the relative position and angle of a single filter. This minimizes the impact of the assembly angle accuracy of the filter on the actual beam splitting effect and improves the coupling efficiency and passband range of the device.

[0031] In this embodiment, the first filter 10 and the second filter 12 are integrated onto the prism 13, and the current wavelength is calibrated to a preset passband range by controlling the coupling position and angle of the prism 13. On the one hand, mounting the first filter 10 and the second filter 12 onto the same prism 13 can better ensure the relative mounting accuracy between the filters; the integrated optical filter 1 can fine-tune the overall optical path inside the device by adjusting its overall position, resulting in higher fault tolerance; on the other hand, by precisely controlling the assembly angle of the prism 13, the packaging yield of the single-fiber bidirectional optical device can be improved, effectively avoiding the problem of poor actual beam splitting effect caused by inaccurate assembly angle, thus improving the performance and stability of the device.

[0032] Example 2: This embodiment proposes a single-fiber bidirectional optical device. In one embodiment, such as... Figure 3 As shown, the device includes a circular-square tube 2, an optical filter 1 as described in Embodiment 1, a transmitting optical device 3, and a receiving optical device 4. The optical filter 1 is disposed inside the circular-square tube 2, and the transmitting optical device 3 and the receiving optical device 4 are disposed on the circular-square tube 2 and coupled to the optical filter 1 respectively. The transmitting optical device 3 is used to emit a first wavelength optical signal, which is coupled to the output optical fiber via the optical filter 1. The receiving optical device 4 is used to receive a second wavelength optical signal obtained after wavelength division by the optical filter 1. The passband range of the single-fiber bidirectional optical device is ensured by adjusting the installation position and angle of the optical filter 1 inside the circular-square tube 2.

[0033] The single-fiber bidirectional optical device further includes a collimation adapter 5, which is coupled to the output end (also the receiving end) of the round-square tube 2 and the output / input optical fiber.

[0034] The transmitting optical device 3 is used to output a first wavelength optical signal (such as a 1310nm optical signal), and the receiving optical device 4 is used to receive a second wavelength optical signal (such as a 1550nm optical signal). This enables a single optical fiber to simultaneously transmit and receive optical signals of different wavelengths. The stability of its passband range (i.e., the wavelength range that allows for effective transmission) depends entirely on the precise control of the installation position and angle of the optical filter 1.

[0035] From a workflow perspective, in one embodiment, the first wavelength optical signal emitted by the transmitting optical device 3 needs to be coupled to the output optical fiber via the optical filter 1, and the second wavelength optical signal transmitted back from the outside needs to be coupled to the receiving optical device 4 via the optical filter 1. The effectiveness of the above two processes depends primarily on the accuracy of the installation position of the optical filter 1. If the filter is offset to the left or right, forward or backward within the circular tube 2, the incident light will deviate from the effective working area of ​​the filter (such as the central film layer area of ​​a thin-film interference filter). Due to differences in film layer thickness at the edge regions or light spot overflow, the target wavelength that should have passed through may be partially blocked, or non-target wavelengths may accidentally enter, causing a shift in the passband center or narrowing of the bandwidth.

[0036] Secondly, it depends on the matching degree of the installation angle of the optical filter 1. The wavelength selectivity of the optical filter 1 is based on the thin film interference principle. The angle between the incident light and the normal of the optical filter 1 directly affects the optical path difference of the light in the film layer. If the angle is too large, the center wavelength will shift to the short wavelength direction and the bandwidth will become wider. If the angle is too small, the center wavelength will shift to the long wavelength direction and the bandwidth will become narrower. If the angle is skewed, it will also cause multiple peaks or stray light interference in the passband, making it impossible to form a stable transmission range.

[0037] Therefore, by adjusting the installation position of the optical filter 1 within the round-square tube 2 (to ensure that the incident light is accurately aligned with the effective area and to solve the problem of optical axis alignment) and the installation angle (to ensure that the incident angle meets the design requirements and to solve the problem of spectral filtering offset), the transmission and reflection functions of the optical filter 1 for light signals of different wavelengths can be accurately realized, thereby stabilizing the passband range of the single-fiber bidirectional optical device and avoiding signal crosstalk or transmission failure.

[0038] Example 3: This embodiment proposes a packaging method for a single-fiber bidirectional optical device. In one embodiment, such as... Figure 4 As shown, the method includes: Step 101: Assemble the optical filter 1.

[0039] In one embodiment, step 101 specifically includes: placing the prism 13 on the substrate 14; and placing the first filter 10 and the second filter 12 on the prism 13 at preset angles to obtain the optical filter 1. The substrate 14 may be a glass substrate 14, and the substrate 14 is a device that directly contacts the inner wall of the round-square tube 2.

[0040] Step 102: Place the optical filter 1 inside the round-square tube 2.

[0041] The circular-square tube 2 has a corresponding square groove inside to accommodate the optical filter 1. The installation position and angle of the optical filter 1 need to be specially designed, which will be explained in detail below.

[0042] Step 103: Place the transmitting optical device 3 on the circular-square tube 2 and place the receiving optical device 4 on the circular-square tube 2 to obtain the single-fiber bidirectional optical device.

[0043] The process involves placing the optical filter 1 inside the square tube 2, and then placing the transmitting optical device 3 and the receiving optical device 4 on the square tube 2. The details will be explained below.

[0044] The encapsulation method of the optical filter 1 in the circular-square tube 2 will be described next. In one embodiment, as follows: Figure 5 As shown, the step of placing the optical filter 1 inside the circular-square tube 2 specifically includes: Step 1021: Apply UV-curable adhesive to the square groove inside the round-square tube 2, place the substrate 14 in the square groove and flatten it so that the substrate 14 comes into contact with the UV-curable adhesive.

[0045] In this process, a certain amount of UV-curable adhesive is applied to the bottom of the groove inside the round-square tube 2, which is used to accommodate the optical filter 1, using a dispensing device. Then, using manual or automated equipment, the entire optical filter 1 is placed into the square groove with its substrate 14 facing down. Slight pressure is applied to flatten the optical filter 1, ensuring that the bottom surface of the substrate 14 is completely in contact with the bottom surface of the square groove in the round-square tube 2, and that it is in full contact with the applied UV adhesive, without air bubbles or gaps.

[0046] Step 1022: Insert the collimation adapter 5 into the transmitting port of the round-square tube 2, and connect an optical fiber patch cord to the collimation adapter 5 to provide the incident light signal; set an optical power meter at the receiving port of the round-square tube 2 to monitor the emitted light power.

[0047] The collimation adapter 5 (containing a precision mechanical assembly with a collimating lens) is inserted into the transmitting port on one side of the round-square tube 2, ensuring proper insertion. A fiber optic patch cord is connected to the external interface of the collimation adapter 5. The other end of this patch cord is connected to a tunable laser to provide the incident light signal. An optical power meter is placed at the receiving port on the other side of the round-square tube 2 to accurately measure the output light power from that port.

[0048] Step 1022 establishes a complete and testable temporary optical system. Light emitted from the tunable laser enters the collimation adapter 5 via an optical fiber patch cord, is converted into collimated light by its internal lens, and then enters the optical filter 1 inside the circular-square tube 2. The optical filter 1 transmits the incident light signal to the optical power meter at the receiving port of the circular-square tube 2. The optical power meter monitors the intensity of the light signal processed by the optical filter 1 in real time and feeds the data back to the operator or control system. The ratio of the output light power Pout to the incident light power Pin (i.e., insertion loss) is the sole basis for fine-tuning the position of the optical filter 1.

[0049] Step 1023: Adjust the position and angle of the optical filter 1 using the fine-tuning device so that the outgoing light power Pout detected by the optical power meter is equal to the incident light power Pin of the incident light signal.

[0050] In this process, the optical filter 1 is picked up with a suction nozzle, and the position and angle of the optical filter 1 are adjusted by a six-dimensional fine-tuning coupling stage so that the output light power Pout detected by the optical power meter is equal to the incident light power Pin at the socket. This indicates that the current wavelength is within the passband of the device.

[0051] In one embodiment, the operator or automatic control system adjusts the six-dimensional fine-tuning coupling stage based on real-time readings from the optical power meter. The adjustment process involves moving or rotating the optical filter 1 along three translation axes (X, Y, Z) and three rotation axes (θx, θy, θz). The goal of the adjustment is to find the optimal position of the optical filter 1 such that, at the current test wavelength, the output optical power Pout of the optical power meter reaches its maximum value and is as close as possible to the value of the incident optical power Pin (i.e., corresponding to minimum insertion loss, ideally 0 dB).

[0052] Step 1024: Adjust the wavelength of the incident light signal to the passband edge wavelength required by the protocol, and confirm that the output light power Pout = the incident light power Pin to verify the passband range.

[0053] After the above adjustments, keep the optical filter 1 in the optimal position found in step 1023. Operate the tunable laser to sequentially adjust the wavelength λ of the incident light signal from the center wavelength to the upper and lower edge wavelengths of the passband specified in the protocol (the range of the passband edge wavelengths is 1303.6nm-1305.6nm, or 1308.1nm-1310.1nm).

[0054] For example, for a certain channel, it could be λ1=1303.6nm and λ2=1305.6nm.

[0055] At each edge wavelength point, observe the optical power meter reading again to confirm whether the output optical power Pout is still equal to (or very close to) the incident optical power Pin. If the deviation is large, it is necessary to return to step 1023 for minor compensatory adjustments.

[0056] In summary, step 1024 ensures that the excellent performance of the device is not just a single point, but a range that meets the requirements. Devices that only pass the center wavelength test may experience performance degradation at the edge wavelengths in actual use. This step ensures that every device produced functions properly throughout the entire channel required by the protocol, fundamentally improving product yield.

[0057] Step 1025: Pre-cur the UV-curable adhesive by irradiation with a UV lamp, and heat-cur the UV-curable adhesive by high-temperature baking, so as to place the optical filter 1 inside the round-square tube 2.

[0058] After confirming that the performance of both the center and edge wavelengths meets the standards through the above four steps, use a UV lamp to irradiate the dispensing area from above the optical filter 1 (for example, for 1 minute). The UV light causes a chemical reaction in the adhesive, which quickly solidifies, temporarily fixing the optical filter 1 in the optimal position and preventing it from shifting during subsequent operations.

[0059] The entire device is then placed in a high-temperature oven for heat curing at a specific temperature (e.g., 120°C) and time (e.g., 1 hour). This step maximizes the adhesive's performance, providing long-term, stable, and reliable mechanical fixation, and enabling it to withstand subsequent high-temperature welding processes and high- and low-temperature operating environments.

[0060] In one embodiment, the packaging method of the single-fiber bidirectional optical device further includes: welding the laser to a cylindrical tube using laser welding, and then attaching an optical isolator inside a groove in the cylindrical tube using adhesive thermosetting to form an emitting laser 31. In one embodiment, the laser welding is a row of flat through-weld welds, with the weld points located at the thickest point of the TO cap of the emitting laser 31, the weld points being 12 points evenly distributed, the adhesive being a two-component thermosetting adhesive, and the high-temperature baking temperature being 85°C for 1.5 hours.

[0061] In one embodiment, a collimating lens is mounted in the lens groove within the round-square tube 2, which has been coupled and cured with an adhesive thermosetting method. Specifically, the adhesive used is a two-component thermosetting adhesive, and the high-temperature baking temperature is 85°C for 1.5 hours.

[0062] In one embodiment, after welding the laser to the cylindrical tube, an optical isolator is mounted inside the cylindrical tube, and a collimating lens is mounted inside the cylindrical tube 2 with the fiber optic filter already coupled and cured. This is the front-end process for coupling the transmitting optical device 3. The emitting laser 31 emits focused light, which is converted into a collimated beam after passing through the collimating lens. This collimated beam can then be coupled into an external optical fiber through the collimating adapter 5.

[0063] In summary, this embodiment, by coupling optical filter 1 and adjusting the wavelength of the input optical signal to both ends of the protocol-required range, if the output optical power Pout and the incident optical power Pin are not significantly different, it proves that the position and angle of the coupled optical filter 1 meet the requirements; otherwise, it is necessary to recouple optical filter 1 and adjust the passband. This precise control of the passband range can effectively avoid the problems of reduced device coupling efficiency and overall passband offset caused by inaccurate passband range, thus improving the applicability and reliability of the device.

[0064] In one embodiment, such as Figure 6 As shown, the single-fiber bidirectional optical device further includes a collimation adapter 5, and the transmitting optical device 3 includes an emitting laser 31 and an adjustment ring 32; in one embodiment, as Figure 7 As shown, the step of mounting the transmitting optical device 3 on the circular-square tube 2 specifically includes: Step 1031: The collimation adapter 5, the round-square tube 2, the adjusting ring 32, and the emitting laser 31 are sequentially clamped onto the coupling welding equipment; wherein, the collimation adapter 5 is inserted into the emission port on the round-square tube 2 and rotates only around the axis, the round-square tube 2 is adjustable only in the Z-axis position, the emitting laser 31 is adjustable in the X-axis and Y-axis directions, and the adjusting ring 32 is sleeved on the bottom of the round-square tube 2 and contacts the emitting laser 31.

[0065] Among them, such as Figure 8 As shown, the collimation adapter 5, the circular tube 2 with built-in optical filter 1, the adjustment ring 32, and the emitting laser 31 (pre-welded to the circular tube with optical isolator to form a TO assembly) are sequentially clamped onto a dedicated coupling welding device in a top-to-bottom order. The upper and lower clamps of the coupling welding device constrain the degrees of freedom of movement of each component, wherein: The collimator adapter 5 is inserted into the transmitting end of the round-square tube 2. The coupling welding equipment allows it to rotate only around its own axis to find the high point direction. The high point direction refers to the specific rotation angle position that maximizes the output optical power when the collimator adapter 5 is rotated.

[0066] The round-square tube 2 is clamped by the upper chuck, and its orientation angle is fixed (i.e. it cannot rotate), but the entire chuck can drive the round-square tube 2 to move up and down along the Z-axis (optical axis direction) for focusing.

[0067] The laser emitter 31 is fixed by the lower clamp and can move in the plane formed by the X and Y axes to find and align the light spot.

[0068] The adjusting ring 32 is fitted onto the protruding structure at the bottom of the round-square tube 2, and the bottom of the adjusting ring 32 contacts the upper surface of the tube body of the laser emitter 31. The adjusting ring 32 itself does not move on its own; its function is to serve as a connector for subsequent laser welding, so as to weld the round-square tube 2 and the laser emitter 31 into a whole.

[0069] In summary, mounting the round / square tube 2, collimator 5, laser emitter 31, and adjusting ring 32 onto the coupling welding equipment constitutes a four-piece coupling welding process. Compared to the conventional three-piece coupling welding process, this process additionally requires a special upper clamp for the round / square tube 2, with a welding window at the upper clamp, and an additional laser welding machine (three welding torches evenly spaced at 120° intervals).

[0070] Referring to the three-piece coupling welding process, the collimator adapter 5 and the round / square tube 2 can be regarded as a whole, corresponding to the adapter in the three-piece coupling welding process. The difference is that the upper clamp only holds the part of the round / square tube 2 that can be moved along the Z-axis (without rotation). Because the collimator adapter 5 is subject to its own gravity, it will move along the round / square tube 2 in the Z-axis direction. At the same time, the collimator adapter 5 can be rotated to the highest point to couple to the maximum power. After finding the optimal highest point of the collimator adapter 5, the collimator adapter 5 and the round / square tube 2 can be pre-fixed and welded by the laser welding machine.

[0071] Step 1032: Power on the emitting laser 31 and adjust the X-axis and Y-axis positions of the emitting laser 31 in sequence to find the optical signal; determine the focal length by adjusting the Z-axis position of the round-square tube 2, rotate the collimating adapter 5 to find the high point direction with the maximum output light power, and pre-fix the collimating adapter 5 in the high point direction to the round-square tube 2 by laser welding.

[0072] The process involves energizing the laser emitter 31 to emit laser light. Then, the lower clamp is controlled to move the X and Y positions of the laser emitter 31. The upper clamp is controlled to move the Z-axis position of the circular-square tube 2, adjusting the optical path to near the focal length to achieve a higher output optical power. Since the coupling efficiency of the collimator 5 varies at different rotation angles (i.e., different height directions), it is necessary to rotate the collimator 5 to find an absolutely optimal angle that maximizes the output optical power.

[0073] Once the optimal high-point orientation is found, a laser welding machine is used to quickly spot weld at the mating gap between the collimator 5 and the round / square tube 2's emission port (for example, welding three points at 120° intervals initially). Specifically, the welding method for pre-fixing the collimator 5 and the round / square tube 2 is lap welding, with the weld points located at the mating gap between the collimator 5 and the round / square tube 2. This temporarily fixes the angular position between the collimator 5 and the round / square tube 2 to prevent subsequent rotation.

[0074] Step 1033: Adjust the X-axis and Y-axis positions of the emitting laser 31 and the Z-axis position of the circular-square tube 2 respectively to maximize the emitted light power; weld the adjusting ring 32 to the circular-square tube 2 and the adjusting ring 32 to the emitting laser 31 by laser welding to complete the coupling of the emitting optical device 3.

[0075] In step 1032, the collimator adapter 5 and the circular-square tube 2 are pre-fixed. The X and Y positions of the emitting laser 31 are then finely adjusted, as is the Z-axis position of the circular-square tube 2, for final fine alignment to ensure the output optical power reaches its absolute maximum. When the output optical power reaches its maximum, the adjustment ring 32 is welded to the circular-square tube 2. The welding method is typically through-welding, where the laser penetrates the wall of the adjustment ring 32 and fuses it to the circular-square tube 2. Alternatively, the adjustment ring 32 can be welded to the tube body of the emitting laser 31 using lap welding, where the laser irradiates the overlapping seam to form a weld point. These weld points are typically multiple evenly distributed points (e.g., 9 or 12 points) to ensure mechanical strength and airtightness.

[0076] At this point, the transmitting optical device 3 is firmly mounted on the round-square tube 2, and the optical path coupling is complete.

[0077] Because the light signal emitted by the laser emitter 31 has a different directional angle, and the mounting angle of the optical filter 1 causes optical path displacement, the overall optical path of each device is different. To achieve maximum coupling, the high-point directions of the laser emitter 31, the circular-square tube 2, and the collimator adapter 5 must be in a defined combination. Without the four-piece coupling welding process proposed in this embodiment, the coupling of the emitting optical device 3 would need to be split into three independent processes: confirming the high-point coupling of the collimator adapter 5; welding the collimator adapter 5 to the circular-square tube 2; and coupling welding of the laser emitter 31. Furthermore, this requires operation on two coupling welding stations, and the front and rear coupling values ​​of the components cannot perfectly correspond, resulting in a low yield.

[0078] In summary, this embodiment mounts the circular-square tube 2, collimator 5, emitting laser 31, and adjusting ring 32 after coupling and solidifying the optical filter 1 onto the coupling welding equipment. Simultaneously, it couples the high point direction and Z-axis of the collimator 5, and the X-axis and Y-axis positions and angles of the emitting laser 31. This allows for the simultaneous coupling and welding of all four components in a single process. This simplified process effectively improves production efficiency, reduces production costs, and enhances production effectiveness.

[0079] In one embodiment, such as Figure 9 As shown, the receiving optical device 4 includes a receiving tube 40, a receiving lens 41, and a receiving detector 42. The process of mounting the receiving optical device 4 on the round-square tube 2 specifically includes: attaching the receiving lens 41 inside the receiving tube 40; welding and fixing the receiving tube 40 to the receiving port of the round-square tube 2 using laser welding; coupling and inserting the receiving detector 42 into the receiving tube 40, adjusting the position of the receiving detector 42 to maximize the responsivity, and fixing the receiving detector 42 to the receiving tube 40 assembly through UV pre-curing and black glue secondary curing.

[0080] The UV adhesive and black adhesive are applied at the gap between the receiver detector 42 and the receiver tube 40. In one embodiment, the UV adhesive can cure for 1 minute, and the black adhesive can be baked at 85°C for 1 hour.

[0081] In one embodiment, since the passband coupling of the receiver has been completed in the early stage, it is only necessary to convert the optical signal received by the receiver into converging light and couple it to the receiver detector 42, which can greatly improve the yield.

[0082] In summary, the optical path design and packaging method of this embodiment can improve the transmission and processing efficiency of optical signals, reduce optical path errors, and improve the accuracy and stability of optical path design. Furthermore, the coupling steps of this embodiment are simple and easy to operate, thus greatly improving production efficiency and reducing production costs. The technology of this embodiment has broad application prospects, large market demand, and high commercial value.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An optical filter, disposed in a single-fiber bidirectional optical device, characterized in that, The optical filter (1) includes: a first filter (10), a second filter (12), and a prism (13); The first filter (10) and the second filter (12) are respectively set on the prism (13) at a preset angle; By adjusting the mounting position and angle of the prism (13) in the single-fiber bidirectional optical device, the passband range of the single-fiber bidirectional optical device can be guaranteed.

2. A single-fiber bidirectional optical device, characterized in that, It includes a round-square tube (2), an optical filter (1) as described in claim 1, an optical device at the transmitting end (3), and an optical device at the receiving end (4); The optical filter (1) is disposed inside the circular tube (2), and the transmitting optical device (3) and the receiving optical device (4) are disposed on the circular tube (2) and coupled to the optical filter (1) respectively. The transmitting optical device (3) is used to emit a first wavelength optical signal, which is coupled to the output optical fiber via the optical filter (1); The receiving optical device (4) is used to receive the second wavelength optical signal obtained after wavelength division by the optical filter (1); The passband range of the single-fiber bidirectional optical device is ensured by adjusting the installation position and angle of the optical filter (1) inside the round-square tube (2).

3. A packaging method for a single-fiber bidirectional optical device, characterized in that, For encapsulating the single-fiber bidirectional optical device as described in claim 2, comprising: Assemble the optical filter (1); The optical filter (1) is disposed inside the round-square tube (2); The transmitting optical device (3) is placed on the round-square tube (2), and the receiving optical device (4) is placed on the round-square tube (2) to obtain the single-fiber bidirectional optical device.

4. The packaging method for a single-fiber bidirectional optical device according to claim 3, characterized in that, The assembly of the optical filter (1) specifically includes: The prism (13) is disposed on the substrate (14); The first filter (10) and the second filter (12) are respectively set on the prism (13) at a preset angle to obtain the optical filter (1).

5. The packaging method for a single-fiber bidirectional optical device according to claim 4, characterized in that, The step of placing the optical filter (1) inside the circular-square tube (2) specifically includes: UV-curable adhesive is applied to the square groove inside the round-square tube (2), and the substrate (14) is placed in the square groove and pressed flat so that the substrate (14) comes into contact with the UV-curable adhesive. Insert the collimation adapter (5) into the transmitting port of the square tube (2) and connect the optical fiber patch cord to the collimation adapter (5) to provide the incident light signal; set an optical power meter at the receiving port of the square tube (2) to monitor the output light power; The position and angle of the optical filter (1) are adjusted by the fine-tuning device so that the outgoing light power Pout detected by the optical power meter is equal to the incident light power Pin of the incident light signal. Adjust the wavelength of the incident light signal to the passband edge wavelength required by the protocol, and confirm that the output light power Pout = the incident light power Pin to verify the passband range; The UV-curing adhesive is pre-cured by UV lamp irradiation and then heat-cured by high-temperature baking to place the optical filter (1) inside the round-square tube (2).

6. The packaging method for a single-fiber bidirectional optical device according to claim 5, characterized in that, The passband edge wavelength range is 1303.6nm-1305.6nm, or 1308.1nm-1310.1nm.

7. The packaging method for a single-fiber bidirectional optical device according to claim 3, characterized in that, The single-fiber bidirectional optical device also includes a collimation adapter (5), and the transmitting optical device (3) includes an emitting laser (31) and an adjustment ring (32). The step of mounting the transmitting optical device (3) on the circular-square tube (2) specifically includes: The collimation adapter (5), the square tube (2), the adjustment ring (32), and the emitting laser (31) are sequentially clamped onto the coupling welding equipment; wherein, the collimation adapter (5) is inserted into the emission port on the square tube (2) and rotates only around the axis, the square tube (2) is adjustable only in the Z-axis position, the emitting laser (31) is adjustable in the X-axis and Y-axis directions, and the adjustment ring (32) is sleeved on the bottom of the square tube (2) and contacts the emitting laser (31); Power on the emitting laser (31) and adjust the X-axis and Y-axis positions of the emitting laser (31) in sequence to find the light signal; determine the focal length by adjusting the Z-axis position of the square tube (2), rotate the collimating adapter (5) to find the high point direction with the maximum output light power, and pre-fix the collimating adapter (5) in the high point direction to the square tube (2) by laser welding; Adjust the X-axis and Y-axis positions of the emitting laser (31) and the Z-axis position of the square tube (2) respectively to maximize the emitted light power; weld the adjusting ring (32) to the square tube (2) and the emitting laser (31) by laser welding to complete the coupling of the emitting optical device (3).

8. The packaging method for a single-fiber bidirectional optical device according to claim 7, characterized in that, The welding method for pre-fixing the collimator (5) and the round square tube (2) is lap welding, and the welding point is located at the mating gap between the collimator (5) and the round square tube (2).

9. The packaging method for a single-fiber bidirectional optical device according to claim 7, characterized in that, The receiving optical device (4) includes a receiving tube (40), a receiving lens (41), and a receiving detector (42). The step of mounting the receiving optical device (4) on the circular tube (2) specifically includes: The receiving lens (41) is attached to the receiving tube (40); The receiving tube (40) and the receiving port of the round-square tube (2) are welded and fixed by laser welding. The receiver detector (42) is coupled into the receiver tube (40), and the position of the receiver detector (42) is adjusted to maximize the responsivity. The receiver detector (42) is fixed in the receiver tube (40) assembly by UV glue pre-curing and black glue secondary curing.

10. The packaging method for a single-fiber bidirectional optical device according to claim 9, characterized in that, The UV adhesive and black adhesive are applied at the gap between the receiver detector (42) and the receiver tube (40).

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