A narrow-band single-fiber four-way combining optical device and a manufacturing method thereof

Abstract

This invention relates to the field of optical communication technology, specifically to a narrowband single-fiber four-way multiplexing optical device and its fabrication method. The device includes a cuboid, on three of which are respectively mounted an optical port, a laser, and a detector. An optical isolator, a cuboid filter, a C-lens, and a first receiving filter are disposed within the cuboid. The laser combines two transmitted wavelengths into one, which is then isolated by the optical isolator, transmitted through the cuboid filter, and passed through the C-lens before entering the optical port. Two received wavelengths from the optical port are reflected by the C-lens, the cuboid filter, and transmitted through the first receiving filter before entering the detector. The detector then splits the two received wavelengths into two paths. This invention highly integrates the optical port, laser, and detector onto a cuboid, enabling both narrowband and high-isolation miniaturization of the optical device. This provides more space for optical module layout, reduces optical crosstalk, ensures signal transmission quality, and improves device reliability.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, specifically to a narrowband single-fiber four-way multiplexing optical device and its fabrication method. Background Technology

[0002] This equipment is used as a node device in the access network. The telecom office equipment connects internal and external networks, completing uplink access to the PON network and acquiring network data sent by user-end equipment. The typical transmission distance is 20km. Currently, single-fiber four-way multiplexer optical devices often connect the two transmitters and two receivers to the base separately, resulting in a large optical module size, hindering miniaturization design. Furthermore, the limited board space for optical module layout leads to high crosstalk between the transmitter and receiver, resulting in low reliability. Summary of the Invention

[0003] The purpose of this invention is to provide a miniaturized narrowband single-fiber four-way multiplexing optical device and its manufacturing method, which can simultaneously achieve narrowband and high isolation, resulting in higher optical module sensitivity, longer transmission distance, more board space, lower optical crosstalk, and higher reliability.

[0004] To achieve the above objectives, the technical solution of the present invention is a narrowband single-fiber four-way combining optical device, comprising a cuboid, on three of its faces respectively mounted an optical port, a laser, and a detector. An optical isolator, a cuboid filter, a C-lens, and a first receiving filter are disposed within the cuboid. The laser combines two emitted wavelengths into one beam, which is then isolated by the optical isolator, transmitted through the cuboid filter, and passed through the C-lens before entering the optical port. Two received wavelengths input to the optical port are reflected by the C-lens and the cuboid filter, transmitted through the first receiving filter, and then enter the detector. The detector splits the two received wavelengths into two beams.

[0005] As one implementation method, the first receiving filter is fixed to the port of the detector end by a receiving filter bracket.

[0006] As one embodiment, the laser end includes a laser end housing, inside which a first laser, a second laser, and an emitting end filter are disposed. The emitted light of the first laser is converted into parallel light by a first glass lens, and the emitted light of the second laser is converted into parallel light by a second glass lens. The two parallel beams are combined into one by transmission and reflection through the emitting end filter.

[0007] As one embodiment, the laser end housing is further provided with a TEC, a first laser heat sink and a second laser heat sink, the first laser is fixed on the first laser heat sink and the second laser is fixed on the second laser heat sink, and both the first laser heat sink and the second laser heat sink are connected to the TEC.

[0008] As one embodiment, an ALN ​​substrate is also disposed inside the laser end housing, and the first laser, the second laser, the heat sink of the first laser, and the heat sink of the second laser are all disposed on the ALN substrate.

[0009] As one implementation method, both the transmitting end filter and the cuboid filter are 45° filters, and the receiving end filter is a 0° filter.

[0010] As one embodiment, a sloping groove is provided at the bottom of the optical hole where the cuboid filter is fixed inside the cuboid, and the sloping groove is inclined downward from the cuboid filter to the optical isolator.

[0011] As one embodiment, the laser end housing includes a BOX tube shell and a BOX tube cover that is sealed on the BOX tube shell.

[0012] As one embodiment, the detector end includes a detector end housing, and a first detector, a second detector, a second receiving end filter, and a third receiving end filter are disposed inside the detector end housing; of the two receiving bands of light incident on the detector end, one receiving band of light is transmitted through the second receiving end filter and then received by the first detector, and the other receiving band of light is reflected by the second receiving end filter and then reflected by the third receiving end filter and then received by the second detector.

[0013] The present invention also provides a method for fabricating a narrowband single-fiber four-way wave combiner optical device, used to fabricate the narrowband single-fiber four-way wave combiner optical device described in any of the above claims, the method comprising the following steps:

[0014] 1) A C-lens, an optical isolator, and a cuboid filter are bonded together inside the cuboid to obtain the first component;

[0015] 2) Attach the first receiving filter to the receiving filter bracket, and attach the receiving filter bracket to the detector end to obtain the second component;

[0016] 3) Attach the transmitter filter to the transmitter filter bracket to obtain the third component;

[0017] 4) Attach the first laser to the heat sink of the first laser to obtain the fourth component;

[0018] 5) Attach the second laser to the heat sink of the second laser to obtain the fifth component;

[0019] 6) Attach the TEC, ALN substrate, fourth component assembled in step 4), fifth component assembled in step 5), and third component assembled in step 3 to the BOX shell to obtain the sixth component;

[0020] 7) Couple the first glass lens and the second glass lens onto the sixth component assembled in step 6) to obtain the seventh component;

[0021] 8) Install the BOX tube cap onto the BOX tube shell of the seventh component assembled in step 7) to obtain the eighth component;

[0022] 9) Install the eighth component onto the first component assembled in step 1) to obtain the ninth component;

[0023] 10) Install the optical port end onto the ninth group assembled in step 9) to obtain the tenth component;

[0024] 11) Install the second component assembled in step 2) onto the tenth component assembled in step 10).

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention integrates the optical port, laser and detector on a cube, which makes the optical device packaging design miniaturized, provides more space for the optical module to be laid out, reduces the degree of optical crosstalk, ensures the quality of signal transmission and improves the reliability of the device.

[0027] (2) The optical path of the device of the present invention is designed with parallel light, which lengthens the optical path and improves the coupling efficiency;

[0028] (3) In this invention, the first receiving end filter is fixed at the port of the detector end by the receiving end filter bracket, which can save coupling space in the component and is more conducive to the miniaturization design of the device.

[0029] (4) The present invention provides a downward inclined groove at the bottom of the optical hole at the fixed cuboid filter in the cuboid body, which is inclined from the cuboid filter to the optical isolator, to prevent optical path reflection and reduce the degree of optical crosstalk between the transmitter and the receiver. Attached Figure Description

[0030] 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.

[0031] Figure 1 This is an external isometric view of the narrowband single-fiber four-way wave combiner in an embodiment of the present invention;

[0032] Figure 2 This is a diagram showing the internal structure of the cube in an embodiment of the present invention;

[0033] Figure 3 This is an external structural diagram of the laser end in an embodiment of the present invention;

[0034] Figure 4 This is a diagram showing the internal structure of the laser end in an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the optical path inside the cube in an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of the optical path of the first emitted wavelength band in an embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of the optical path of the second emitted wavelength band in an embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the optical paths for receiving light in two different wavelength bands in an embodiment of the present invention.

[0039] In the diagram: 1. Optical port; 2. Cuboid; 3. Laser end; 4. Detector end; 5. Receiver filter bracket; 6. First receiver filter; 7. C-lens; 8. Cuboid filter; 9. Optical isolator; 10. Sloping groove; 11. BOX shell; 12. BOX cover; 13. First laser heat sink; 14. First laser; 15. First glass lens; 16. ALN substrate; 17. TEC; 18. Transmitter filter bracket; 19. Transmitter filter; 20. Second glass lens; 21. Second laser; 22. Second laser heat sink; 23. Second receiver filter; 24. Third receiver filter; 25. First detector; 26. Second detector. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0042] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0043] Example 1

[0044] like Figures 1-5 As shown, this embodiment provides a narrowband single-fiber four-way combining optical device, including a cuboid 2. An optical port 1, a laser end 3, and a detector end 4 are respectively mounted on three of the faces of the cuboid 2. An optical isolator 9, a cuboid filter 8, a C-lens 7, and a first receiving end filter 6 are disposed within the cuboid 2. The laser end 3 combines two emitted wavelengths into one, which is then isolated by the optical isolator 9, transmitted through the cuboid filter 8, and passed through the C-lens 7 before entering the optical port 1. The two received wavelengths input to the optical port 1 are reflected by the C-lens 7 and the cuboid filter 8, transmitted through the first receiving end filter 6, and then enter the detector end 4. The detector end 4 splits the two received wavelengths into two paths. In this embodiment, the laser end 3 is used to combine two transmitted light bands into one path, the detector end 4 is used to split two received light bands into two paths, and the cube 2 is used to connect each port and serve as a carrier for each related optical component. The cube 2 highly integrates the optical port 1, the laser end 3, and the detector end 4, enabling the miniaturization of optical devices that simultaneously achieve narrowband and high isolation, reserving more board space for the optical module, reducing optical crosstalk, ensuring the quality of signal transmission, and making the optical module more sensitive and with a longer transmission distance.

[0045] In an optimized embodiment, the first receiving filter 6 is fixed to the port of the detector end 4 via a receiving filter bracket 5. Specifically, the receiving filter bracket 5 is designed as a ring and adhered to the port of the detector end 4, thereby fixing the first receiving filter 6 to the detector end 4. This saves coupling space in the component and facilitates miniaturization design of the device.

[0046] As one embodiment, the laser end 3 includes a laser end 3 housing. A first laser 14, a second laser 21, and an emitter filter 19 are disposed within the laser end 3 housing. The emitter filter 19 is fixed to the laser end 3 housing by an emitter filter 19 bracket 18. The emitted wavelength light from the first laser 14 is converted into parallel light by a first glass lens 15, and the emitted wavelength light from the second laser 21 is converted into parallel light by a second glass lens 20. The two parallel beams are transmitted and reflected by the emitter filter 19 and combined into a single beam. This embodiment uses glass lenses and a C-lens 7 to design a parallel light path, lengthening the optical path while improving coupling efficiency.

[0047] To ensure that the optical path is not blocked and the coupling efficiency is not affected, the optical isolator 9 in this embodiment can be an optical isolator 9 with a large aperture. Without affecting the structure, the aperture is close to the limit, which can receive more light from the laser end 3, ensuring the maximum coupling efficiency and light spot quality.

[0048] Furthermore, the laser terminal 3 housing also includes a TEC17 (semiconductor cooler), a first laser 14 heat sink 13, and a second laser heat sink 22. The first laser 14 is fixed to the first laser 14 heat sink 13, and the second laser 21 is fixed to the second laser heat sink 22. Both the first laser 14 heat sink 13 and the second laser heat sink 22 are connected to the TEC17. In this embodiment, the laser is cooled by the heat sink, and the TEC17 is used to maintain the heat sink at a constant temperature, achieving stable spectral output of the laser. At the same time, the laser terminal 3 is sealed to isolate moisture, avoid corrosion and oxidation of the internal metal of the device, ensure the stable operating environment of the TEC17 and the laser, and improve the reliability of the device.

[0049] Furthermore, an ALN ​​(aluminum nitride) substrate is also disposed inside the housing of the laser end 3, and the first laser 14, the second laser 21, the heat sink 13 of the first laser 14, and the heat sink 22 of the second laser are all disposed on the ALN substrate 16. At the same time, the first laser 14 and the second laser 21 adopt a TO CAN-like lead wire design to facilitate gold wire bonding and external power supply.

[0050] To improve the quality of transmitted signals, impedance matching simulation design was performed on the laser carrier pattern design at laser end 3. This design ensures signal transmission matching and quality while fixing the laser, and optimizes the eye diagram.

[0051] Ideally, both the transmitting filter 19 and the cuboid filter 8 are 45° filters, and the receiving filter is a 0° filter.

[0052] To ensure low crosstalk at the receiving end, in this embodiment, a ramp groove 10 is provided at the bottom of the optical aperture where the cuboid filter 8 is fixed inside the cuboid 2. The ramp groove 10 is inclined downward from the cuboid filter 8 to the optical isolator 9 to prevent optical path reflection and reduce the degree of optical crosstalk from the transmitting end to the receiving end.

[0053] As one embodiment, the laser terminal 3 housing includes a BOX housing 11 and a BOX cover 12 sealing the BOX housing 11. To improve device integration and reliability, the laser terminal 3 in this embodiment adopts a WDM (wavelength division multiplexing) multiplexing design, and the packaging adopts a BOX design, highly integrating two lasers. High thermal conductivity silver paste is used internally to ensure heat dissipation inside the device, improving the high-temperature heat dissipation performance of the device.

[0054] To achieve a shortened component design, the laser end optical path adhesive uses high-reliability epoxy resin adhesive used in the optical communication industry, which ensures reliability while fixing the optical path; the filter bracket in the laser end 3BOX adopts a miniaturized design, which saves BOX space while supporting the transmitting end filter.

[0055] In detail, the detector end 4 includes a detector end 4 housing, within which are disposed a first detector 25, a second detector 26, a second receiving filter 23, and a third receiving filter 24. Two receiving wavelengths of light input from the optical port 1 first pass through the C-lens 7, then are reflected by the cuboid filter 8, and then perpendicularly enter the first receiving filter 6. After being transmitted through the first receiving filter 6, they enter the detector end 4. Of the two receiving wavelengths of light entering the detector end 4, one wavelength is transmitted through the second receiving filter 23 and then perpendicularly enters the first detector 25; the other wavelength is reflected by the second receiving filter 23 and the third receiving filter 24, and then perpendicularly enters the second detector 26. Both the second receiving filter 23 and the third receiving filter 24 can be 45° filters and are arranged in parallel. The two receiving wavelengths of light are perpendicularly incident on the first detector 25 and the second detector 26, respectively, improving the coupling efficiency of the detectors.

[0056] In this embodiment, both the laser end 3 and the detector end 4 are provided with pins. In order to achieve device miniaturization, the pin length is designed to be close to the limit while ensuring the optical port protocol standard, and at the same time ensuring the reliability of the pins and laser welding.

[0057] In this embodiment, the total length of the device can be shortened to 28mm. The cuboid 2, the outer shell of the laser end 3, the emitter filter 19, and the bracket 18 are required to have an angle tolerance of ±0.5° and a dimensional tolerance of ±0.05mm. Local areas are required to undergo root clearing and flatness treatment.

[0058] Example 2

[0059] This embodiment provides a method for fabricating a narrowband single-fiber four-way wave combiner optical device, used to fabricate the narrowband single-fiber four-way wave combiner optical device provided in Embodiment 1. The method includes the following steps:

[0060] 1) The order in which the optical components are bonded inside the cuboid 2 is as follows: C-lens 7, optical isolator 9, and cuboid filter 8, to obtain the first component; wherein, the cuboid 2 is bonded to C-lens 7, cuboid filter 8, and optical isolator 9 using high-reliability epoxy adhesive, and the shear force meets industry requirements.

[0061] 2) Attach the first receiving end filter 6 to the receiving end filter bracket 5, and attach the receiving end filter bracket 5 to the detector end 4 to obtain the second component;

[0062] 3) Attach the transmitter filter 19 to the transmitter filter 19 bracket 18 to obtain the third component;

[0063] 4) The first laser 14 is bonded to the heat sink 13 of the first laser 14 to obtain the fourth component;

[0064] 5) Attach the second laser 21 to the second laser heat sink 22 to obtain the fifth component;

[0065] 6) The order in which the optical components are bonded to the BOX housing 11 is as follows: TEC17, ALN substrate 16, fourth component assembled in step 4), fifth component assembled in step 5), and third component assembled in step 3, to obtain the sixth component.

[0066] 7) Couple the first glass lens 15 and the second glass lens 20 to the sixth component assembled in step 6) to obtain the seventh component;

[0067] 8) Install the BOX tube cap 12 onto the BOX tube shell 11 of the seventh component assembled in step 7) to obtain the eighth component;

[0068] 9) Install the eighth component onto the first component assembled in step 1) to obtain the ninth component; specifically, the eighth component is fixed to the cube 2 by laser welding to ensure the shear force and reliability of the product;

[0069] 10) Install the optical port 1 onto the ninth group assembled in step 9) to obtain the tenth component; specifically, the optical port 1 and the cube 2 are fixed by laser welding to ensure the stability of the product;

[0070] 11) Install the second component assembled in step 2) onto the tenth component assembled in step 10).

[0071] In this embodiment, the wavelength of the emitted light emitted by the first laser 14 is 1577nm, and the wavelength of the emitted light emitted by the second laser 21 is 1490nm; the passband of the cuboid filter 8 is 1480~1650nm and the stopband is 1240~1400nm to ensure crosstalk of the optical devices; the passband of the emitting filter 19 is 1520~1650nm and the stopband is 1460~1520nm to ensure the isolation of the optical devices.

[0072] like Figure 6 As shown, the 1577nm divergent light emitted by the first laser 14 is converted into parallel light by the first glass lens 15, passes through the emitter filter 19, enters the optical isolator 9, enters and passes through the cuboid filter 8 through the deflection and refraction of the optical isolator 9, and then passes through the C-lens 7 to convert the parallel light into convergent light. The convergent light is then coupled and focused to the optical port 1.

[0073] like Figure 7 The 1490nm diverging light emitted by the second laser 21 is converted into parallel light by the second glass lens 20, passes through the emitter filter 19, enters the optical isolator 9, enters and passes through the cuboid filter 8 through the deflection and refraction of the optical isolator 9, and then passes through the C-lens 7 to convert the parallel light into convergent light. The convergent light is coupled and converged to the optical port 1, realizing the wave combination with the 1577nm end.

[0074] like Figure 8 As shown, the combined 1270nm and 1310nm light is converted into parallel light by C-lens 7, reflected by cuboid filter 8, passes through the first receiving filter 6, and enters the housing of detector 4. The 1270nm receiving band light passes through the second receiving filter 23 and enters the first detector 25. The 1310nm receiving band light is reflected by the second receiving filter 23 and the third receiving filter 24 and enters the second detector 26, thus separating the 1270nm receiving band light from the 1310nm receiving band light.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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. A narrowband single-fiber four-way wave combining optical device, comprising a cuboid, characterized in that: An optical port, a laser, and a detector are respectively mounted on three faces of the cuboid. An optical isolator, a cuboid filter, a C-lens, and a first receiving filter are disposed within the cuboid. The laser combines two emitted wavelengths into one beam, which is then isolated by the optical isolator, transmitted through the cuboid filter, and passed through the C-lens before entering the optical port. Two received wavelengths from the optical port are reflected by the C-lens, the cuboid filter, and transmitted through the first receiving filter before entering the detector. The detector splits the two received wavelengths into two beams. A ramp groove is provided at the bottom of the optical aperture where the cuboid filter is fixed within the cuboid, and the ramp groove is inclined downwards from the cuboid filter to the optical isolator. The first receiving filter is fixed to the port of the detector via a receiving filter bracket.

2. The narrowband single-fiber four-way beam combining optical device as described in claim 1, characterized in that: The laser end includes a laser end housing, inside which a first laser, a second laser, and an emitting end filter are disposed. The emitted light of the first laser is converted into parallel light by a first glass lens, and the emitted light of the second laser is converted into parallel light by a second glass lens. The two parallel beams are combined into one beam through transmission and reflection by the emitting end filter.

3. The narrowband single-fiber four-way wave combiner as described in claim 2, characterized in that: The laser end housing is further provided with a TEC, a first laser heat sink, and a second laser heat sink. The first laser is fixed on the first laser heat sink, and the second laser is fixed on the second laser heat sink. Both the first laser heat sink and the second laser heat sink are connected to the TEC.

4. The narrowband single-fiber four-way wave combiner as described in claim 3, characterized in that: An ALN ​​substrate is also disposed inside the laser end housing, and the first laser, the second laser, the heat sink of the first laser, and the heat sink of the second laser are all disposed on the ALN substrate.

5. The narrowband single-fiber four-way wave combiner as described in claim 2, characterized in that: Both the transmitting end filter and the cuboid filter are 45° filters, and the receiving end filter is a 0° filter.

6. The narrowband single-fiber four-way beam combining optical device as described in claim 1, characterized in that: The laser end housing includes a BOX tube shell and a BOX tube cover with a sealing cap disposed on the BOX tube shell.

7. The narrowband single-fiber four-way wave combiner as described in claim 1, characterized in that: The detector end includes a detector end housing, and a first detector, a second detector, a second receiving end filter, and a third receiving end filter are disposed inside the detector end housing; of the two receiving bands of light incident on the detector end, one receiving band of light is transmitted through the second receiving end filter and then received by the first detector, and the other receiving band of light is reflected by the second receiving end filter and then reflected by the third receiving end filter and then received by the second detector.

8. A method for fabricating a narrowband single-fiber four-way wave combiner, characterized in that: The method for fabricating the narrowband single-fiber four-way wave combiner optical device according to any one of claims 1-7 comprises the following steps: 1) A C-lens, an optical isolator, and a cuboid filter are bonded together inside the cuboid to obtain the first component; 2) Attach the first receiving filter to the receiving filter bracket, and attach the receiving filter bracket to the detector end to obtain the second component; 3) Attach the transmitter filter to the transmitter filter bracket to obtain the third component; 4) Attach the first laser to the heat sink of the first laser to obtain the fourth component; 5) Attach the second laser to the heat sink of the second laser to obtain the fifth component; 6) Attach the TEC, ALN substrate, fourth component assembled in step 4), fifth component assembled in step 5), and third component assembled in step 3 to the BOX shell to obtain the sixth component; 7) Couple the first glass lens and the second glass lens onto the sixth component assembled in step 6) to obtain the seventh component; 8) Install the BOX tube cap onto the BOX tube shell of the seventh component assembled in step 7) to obtain the eighth component; 9) Install the eighth component onto the first component assembled in step 1) to obtain the ninth component; 10) Install the optical port end onto the ninth group assembled in step 9) to obtain the tenth component; 11) Install the second component assembled in step 2) onto the tenth component assembled in step 10).

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