Optical receiving device and optical transmission module

Abstract

The invention provides an optical receiving device and an optical transmission module, and relates to the technical field of optical fiber communication. The optical receiving device comprises an optical port upper piece and a coaxial packaging receiving piece. The optical port upper piece comprises a shell and an optical fiber bare fiber arranged in the shell. The optical fiber bare fiber comprises a first end and a second end which are oppositely arranged. The mode field diameter of the first end is larger than that of the second end. The second end is connected with an external optical fiber. The coaxial packaging receiving piece comprises a tube base and a photoelectric detector arranged on the tube base. The first end face of the optical fiber bare fiber faces the photoelectric detector and is in optical coupling connection with the photoelectric detector. And the tube seat is fixedly connected with the shell. The optical receiving device is suitable for a photoelectric detector with a small photosensitive surface, the responsivity of the photoelectric detector is not sacrificed while the high bandwidth is met, the coupling efficiency is improved, and the photoelectric performance of a coaxial packaging receiving piece in a high-speed scene is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical fiber communication technology, in particular to an optical receiving device and an optical transmission module. BACKGROUND

[0002] In the optical communication industry, the optical transmission module is mainly a signal transmission module for converting electrical signals into optical signals and converting optical signals into electrical signals; the device in the optical transmission module for converting optical signals into electrical signals is an optical receiving device.

[0003] With the increase of optical communication module rate, the bandwidth of the photoelectric detector chip at the receiving end is increased, and the light-sensitive surface of the photoelectric detector is gradually reduced. With the further reduction of the light-sensitive surface of the photoelectric detector, the traditional airtight receiving device cannot be adapted, and in order to adapt to the smaller light-sensitive surface, the response of the device is usually sacrificed to a certain extent, thereby affecting the sensitivity of the overall device. SUMMARY

[0004] The purpose of the present application includes, for example, providing an optical receiving device and an optical transmission module which can be applied to a photoelectric detector with a small light-sensitive surface without affecting the sensitivity of the optical receiving device, so as to improve the photoelectric coupling efficiency.

[0005] Embodiments of the present application can be implemented as follows:

[0006] In a first aspect, the present application provides an optical receiving device, comprising:

[0007] An optical port-on device, comprising a shell and a fiber bare fiber arranged in the shell, the fiber bare fiber comprising a first end and a second end arranged oppositely, the mode field diameter of the first end being larger than that of the second end; the second end being used for connecting with an external optical fiber;

[0008] A coaxial packaging receiving device, comprising a tube seat and a photoelectric detector arranged on the tube seat, the first end of the fiber bare fiber facing the photoelectric detector and being optically coupled with the photoelectric detector, and the tube seat being fixedly connected with the shell.

[0009] In an optional embodiment, the first end is an expanded beam end, and the second end is a conventional end.

[0010] In an optional embodiment, the coaxial packaging receiving device further comprises a tube cap and a lens, the tube cap is connected with the tube seat, the lens is installed on the tube seat, and the lens is located in the tube cap, and the shell is connected with the tube cap.

[0011] In an optional embodiment, a support column is arranged on the tube seat, and the lens is installed on the support column.

[0012] In an optional embodiment, the base is provided with a mounting surface near one end of the housing, and the photoelectric detector is arranged on the mounting surface.

[0013] The support column is arranged on the mounting surface and located at the periphery of the mounting surface.

[0014] In an optional embodiment, the coaxial package receptacle further comprises a transition ring, which is arranged on the support column, and the lens is arranged on the transition ring.

[0015] In an optional embodiment, the transition ring and the support column are welded or bonded.

[0016] In an optional embodiment, the support column and the base are integrally formed.

[0017] In an optional embodiment, the end surface of the first end is not perpendicular to the axis of the housing.

[0018] In a second aspect, the application provides an optical transmission module comprising the optical receiving device as described in any one of the preceding embodiments.

[0019] The beneficial effects of the embodiments of the application include, for example:

[0020] The optical receiving device provided by the embodiments of the application designs the mode field diameters of the two ends of the bare fiber of the optical fiber in the optical port as an asymmetric form, i.e., the mode field diameter of the first end of the bare fiber is greater than that of the second end. The second end is used to connect with an external optical fiber, and the first end is optically coupled with a photoelectric detector. Since the mode field diameter of the first end is larger, the coupling efficiency is higher when coupled with the photoelectric detector, and it is especially suitable for photoelectric detectors with small light-sensitive surfaces. This design will not affect the sensitivity of the optical receiving device, and is conducive to improving the coupling efficiency.

[0021] The optical transmission module provided by the embodiments of the application comprises the optical receiving device described above, and can be suitable for photoelectric detectors with small light-sensitive surfaces without affecting the sensitivity of the optical receiving device, so as to improve the photoelectric coupling efficiency of the receiving end. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0023] Figure 1 The structure diagram of the optical receiving device provided by the embodiments of the application;

[0024] Figure 2 A structure diagram of the expanded-beam fiber in the light receiving device provided by the embodiment of the present application;

[0025] Figure 3 A structure diagram of the expanded-beam fiber in the light receiving device provided by the embodiment of the present application;

[0026] Figure 4 A structure diagram of the expanded-beam fiber in the light receiving device provided by the embodiment of the present application;

[0027] Figure 5 A structure diagram of the expanded-beam fiber in the light receiving device provided by the embodiment of the present application;

[0028] Figure 6 A structure diagram of the expanded-beam fiber in the light receiving device provided by the embodiment of the present application;

[0029] Figure 7 A structure diagram of the expanded-beam fiber in the light receiving device provided by the embodiment of the present application;

[0030] Figure 8 A structure diagram of the expanded-beam fiber in the light receiving device provided by the embodiment of the present application;

[0031] Figure 9 A structure diagram of the expanded-beam fiber in the light receiving device provided by the embodiment of the present application;

[0032] Figure 10 A structure diagram of the expanded-beam fiber in the light receiving device provided by the embodiment of the present application;

[0033] Figure 11 A structure diagram of the expanded-beam fiber in the light receiving device provided by the embodiment of the present application;

[0034] Figure: 10 - light receiving device; 100 - optical port component; 110 - shell; 120 - fiber bare fiber; 121 - first end; 123 - second end; 125 - core; 127 - cladding; 130 - ordinary single-mode fiber; 200 - coaxial packaging receiving component; 210 - tube seat; 220 - photodetector; 230 - lens; 240 - tube cap; 250 - transition ring; 260 - support column; 270 - structural adhesive. DETAILED DESCRIPTION

[0035] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work under the premise that the scope of the present application is protected.

[0037] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0038] In the description of the present application, it should be noted that if the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0039] In addition, if the terms "first", "second" and the like appear, they are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0040] It should be noted that the features in the embodiments of the present application can be combined with each other without conflict.

[0041] Please refer to Figure 1 , Figure 2 and Figure 7The embodiment provides an optical receiving device 10 which can convert an optical signal into an electrical signal. The optical receiving device 10 comprises an optical port-on component 100 and a coaxial package receiving component 200. The optical port-on component 100 comprises a shell 110 and a fiber bare fiber 120 arranged in the shell 110. The fiber bare fiber 120 comprises a first end 121 and a second end 123 which are oppositely arranged, and a mode field diameter of the first end 121 is larger than that of the second end 123. The second end 123 is used for connecting with an external optical fiber. The coaxial package receiving component 200 comprises a tube base 210, a tube cap 240, a lens 230, a transition ring 250 and a photodetector 220 arranged on the tube base 210. The first end 121 of the fiber bare fiber 120 faces the photodetector 220 and is optically coupled with the photodetector 220, and the tube base 210 and the shell 110 are fixedly connected together. The photodetector 220 is used for converting the optical signal into the electrical signal. In the optical receiving device 10, because the mode field diameter of the first end 121 is larger, the first end 121 is suitable for coupling with the photodetector 220 with a smaller light-sensitive surface, the high bandwidth is met, the responsivity of the photodetector 220 is not sacrificed, the coupling efficiency is improved, and the photoelectric performance of the coaxial package receiving component 200 in a high-speed scene is ensured.

[0042] In the embodiment, the first end 121 is an expanded beam end, and the second end 123 is a conventional end. The first end 121 can be precisely fired on a single-mode optical fiber. For example, the first end 121 is expanded in the end face by using thermal expansion or other processes, so that the mode field diameter of the first end 121 is larger, which is conducive to coupling with the photodetector 220 with a small light-sensitive surface, improves the coupling efficiency, and does not affect the sensitivity of the receiving device. The specific parameters of the expanded beam end need to be determined according to the specific optical design. The second end 123 is a conventional end, that is, the end face of the second end 123 is the same as that of the existing optical fiber. The conventional end does not affect the adaptation with the conventional external optical fiber and does not need to be changed. In the embodiment, only the end of the fiber bare fiber 120 which is optically coupled with the photodetector 220 needs to be improved by expansion, and the improvement cost is low. It can be understood that the fiber bare fiber 120 comprises a fiber core 125 and a cladding 127 which is wrapped outside the fiber core 125. The end face of the fiber core 125 of the first end 121 is expanded by thermal expansion, so as to increase the mode field diameter of the first end 121. The fiber bare fiber 120 is further wrapped with a ceramic (not shown in the figure) to form a ferrule, and the ferrule is fixedly connected with the shell 110.

[0043] In combination Figure 3 , Figure 3 is a structural schematic view of a conventional single-mode optical fiber, that is, both ends are conventional ends. The mode field diameters of the end faces of the two ends of the optical fiber are equal, and the two ends are symmetrically designed. The mode field diameter MFD (1550 nm) of the conventional end of the ordinary single-mode optical fiber 130 is about 10.4 um, the 1% NA is about 0.14, and the two ends of the optical fiber have the same MFD and NA values.

[0044] In this embodiment, the fiber bare fiber 120 uses a beam expanding fiber to perform beam expanding processing on the fiber core 125 of the first end 121, so that the mode field diameter MFD of the beam expanding end is greater than 10.4 um, the divergence angle of the fiber bare fiber 120 at the first end 121 is reduced, the numerical aperture NA value is reduced, and the 1% NA is less than 0.14. In this way, the MFD of the fiber bare fiber 120 is increased and the numerical aperture NA value is reduced at the end close to the photodetector 220, thereby reducing the coupling difficulty of the small light sensitive surface PD. The second end 123 in this embodiment is a conventional end, that is, the mode field diameter MFD is about 10.4 um, and the 1% NA is about 0.14. Of course, in other embodiments, the mode field diameters of the two ends are not limited to the above-mentioned values, and the mode field diameter of the first end 121 can be flexibly set according to the type of the photodetector 220. As long as the mode field diameter of the first end 121 is greater than that of the second end 123.

[0045] It should be noted that in the paraxial region, the ratio of the size y' of the image to the size y of the object is called the transverse magnification, denoted by the Greek letter β:

[0046]

[0047] In the application of the receiving end, it is desirable for the optical system to have a smaller transverse magnification, so as to obtain a smaller image under the condition that the object has the same or similar size.

[0048] The angular magnification γ is the ratio of the angle u' between a pair of conjugate rays and the optical axis to the angle u between the object point and the optical axis, denoted by the Greek letter γ:

[0049]

[0050] where n is the refractive index of the object-side medium, and n' is the refractive index of the image-side medium.

[0051] As described above, in the application of the receiving end, it is desirable for the optical system to have a smaller transverse magnification. It can be found from the above formula that the angular magnification γ is inversely proportional to the transverse magnification β. Therefore, in order to reduce the transverse magnification of the optical system, we need to increase the angular magnification. It can also be found from the above formula that the angular magnification can be increased by reducing the angle u between the object-side ray and the optical axis or increasing the object distance l, or reducing the image distance l'.

[0052] In this embodiment, in order to further improve the corresponding coupling efficiency of the small light sensitive surface photodetector 220, the first end 121 is a thermal beam expanding fiber bare fiber 120 (TEC Fiber). Compared with the ordinary single-mode fiber 130, the thermal beam expanding fiber bare fiber 120 can effectively reduce the angle u between the object-side ray and the optical axis, thereby facilitating the increase of the angular magnification and the reduction of the transverse magnification.

[0053] In addition, it should be understood that the light propagates in the special asymmetric beam expanding fiber bare fiber 120 in this embodiment. If the light propagates from the photodetector 220 to the light port upper piece 100 along the optical axis of the coaxial packaging receiving piece 200, the insertion loss is large during the propagation. If it propagates from the light port upper piece 100 to the photodetector 220, the insertion loss is small. Thus, this design of the embodiment can adapt to the application of the receiving end, that is, for use in the optical receiving device 10.

[0054] During the light propagation, the back light propagates from the photodetector 220 to the light port upper piece 100, and the insertion loss is large. Coating can be performed on the first end 121 to improve the back loss. Alternatively, the end face of the first end 121 is designed as an inclined inclined surface, that is, the end face of the first end 121 is not perpendicular to the axis of the shell 110, and the axis of the shell 110 is consistent with the axis of the fiber bare fiber 120. In this way, the back loss can also be further improved, as shown in Figure 4 .

[0055] In combination with Figure 5 and Figure 6 , Figure 5 , the optical path schematic diagram when the fiber propagates in the embodiment of the present application is shown in Figure 3 . Figure 6 The optical path schematic diagram when the fiber bare fiber 120 propagates in the embodiment of the present application is shown in Figure 2 , the first end 121 is a beam expanding end, and the second end 123 is a conventional end. It can be seen that in the case of the same lens 230, compared with the ordinary single-mode fiber 130 with both ends being conventional ends, when the beam expanding end in the embodiment propagates to the photodetector 220, the distance between the lens 230 and the photodetector 220 is closer, and the distance between the lens 230 and the first end 121 is farther. That is, the lens 230 is closer to the photodetector 220, which realizes increasing the object distance l and reducing the image distance l', so as to increase the angular magnification and obtain smaller vertical magnification, thereby improving the photoelectric performance.

[0056] It is easy to understand that in the optical receiving device 10 in the embodiment, the distance between the lens 230 and the photodetector 220 is closer, and the relative positions of the two have higher requirements. The passive scheme (high-precision mounting and capping equipment) can be used to ensure the positions of the lens 230 and the photodetector 220, or the active scheme (lens 230 coupling process) can be used to ensure the positions of the lens 230 and the photodetector 220. In the embodiment, the coaxial packaging receiving piece 200 is designed based on the active scheme, and the structure of the special coaxial packaging receiving piece 200 is adapted to the optical path characteristics.

[0057] In combination with Figure 7 to Figure 9In order to realize the stable installation of the lens 230, the support column 260 is arranged on the pipe base 210, the transition ring 250 is arranged on the support column 260, and the lens 230 is arranged on the transition ring 250. The lens 230 is arranged on the support column 260. It should be noted that, since the distance between the lens 230 and the photoelectric detector 220 is very close, it is difficult to accommodate the installation of the pipe cap 240, while the distance between the lens 230 and the first end 121 is relatively far. Therefore, in the embodiment, the lens 230 is arranged in the pipe cap 240, that is, the pipe cap 240 is located between the lens 230 and the shell 110.

[0058] The end of the pipe base 210 close to the shell 110 comprises a mounting surface, and the mounting surface is provided with a mounting area. The photoelectric detector 220 is arranged in the mounting area. Of course, in addition to the photoelectric detector 220, elements such as transimpedance amplifiers, resistors, capacitors and the like are also arranged in the mounting area. The support column 260 is arranged on the mounting surface and located at the periphery of the mounting area. That is, the arrangement of the support column 260 will not affect the mounting of the photoelectric detector 220 and other elements.

[0059] Optionally, the support column 260 and the pipe base 210 are integrally formed. For example, the pipe base 210 and the support column 260 are integrally formed by stamping. Of course, the support column 260 can also be fixed on the pipe base 210 by welding, bonding, riveting and the like, which is not limited here. The support column 260 can be a metal column, which is structurally reliable and convenient for welding with other elements. The number, shape and distribution position of the support column 260 can be flexibly set, which can be one, two, three, four or more, as long as it does not interfere with the mounting of the elements in the mounting area and can stably support and fix the transition ring 250 and the lens 230.

[0060] In combination Figure 10 And Figure 11 Optionally, the transition ring 250 and the support column 260 are welded or bonded. The lens 230 is welded or bonded with the transition ring 250. During assembly, the lens 230 and the photoelectric detector 220 are first coupled, and after coupling, the lens 230 is laser welded on the transition ring 250, and the transition ring 250 is laser welded on the support column 260. After the coupling and fixing of the lens 230 are completed, the pipe cap 240 and the pipe base 210 are welded by using energy storage welding to form a sealed airtight cavity, thereby ensuring the reliability of the internal devices. Finally, the first end 121 of the optical port upper piece 100 is coupled and fixed with the coaxial packaging receiving piece 200. Optionally, the shell 110 of the optical port upper piece 100 and the pipe cap 240 are fixedly connected, for example, by laser welding or bonding. In the embodiment, the shell 110 is sleeved on the pipe cap 240, and a structure adhesive 270 is formed after baking and curing to realize the fixed connection of the pipe cap 240 and the optical port upper piece 100.

[0061] The light receiving device 10 provided by the embodiment is configured such that the light propagates in the direction from the light port component 100 to the photodetector 220. Specifically, the light propagates from the regular end of the fiber bare fiber 120 to the expanded beam end, and then propagates from the expanded beam end to the photodetector 220 through the lens 230, thereby achieving the light receiving function. The light enters the photodetector 220 from the expanded beam end. The expanded beam end has a larger mode field diameter and a smaller numerical aperture, which is conducive to coupling with the photodetector 220 having a small light-sensitive surface, and the coupling efficiency is high and the insertion loss is small. In addition, in this way, the distance between the lens 230 and the photodetector 220 is closer, and the distance between the lens 230 and the expanded beam end is farther, thereby increasing the object distance l and reducing the image distance l', so as to increase the angular magnification and obtain a smaller vertical magnification, thereby improving the photoelectric performance.

[0062] The embodiment of the present application also provides an optical transmission module comprising the light receiving device 10 according to any one of the preceding embodiments. The optical transmission module can be a light receiving device only having a light receiving function, or a light transceiver having both a light transmitting function and a light receiving function. When the optical transmission module is implemented as a light transceiver, the optical transmission module further comprises a light emitting component.

[0063] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed by the present application can be easily conceived by those skilled in the art, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An optical receiving device, characterized in that, include: An optical port mount (100) includes a housing (110) and a bare optical fiber (120) disposed within the housing (110). The bare optical fiber (120) includes a first end (121) and a second end (123) disposed opposite to each other. The mode field diameter of the first end (121) is larger than that of the second end (123). The second end (123) is used to connect to an external optical fiber. A coaxial packaged receiver (200) includes a socket (210) and a photodetector (220) disposed on the socket (210). The first end (121) of the bare optical fiber (120) is disposed facing the photodetector (220) and is optically coupled to the photodetector (220). The socket (210) and the housing (110) are fixedly connected.

2. The optical receiving device according to claim 1, characterized in that, The first end (121) is the beam expanding end, and the second end (123) is the conventional end.

3. The optical receiving device according to claim 1, characterized in that, The coaxial packaged receiver (200) further includes a cap (240) and a lens (230), the cap (240) being connected to the base (210), the lens (230) being mounted on the base (210), and the lens (230) being located inside the cap (240); the housing (110) is connected to the cap (240).

4. The optical receiving device according to claim 3, characterized in that, The tube base (210) is provided with a support column (260), and the lens (230) is mounted on the support column (260).

5. The optical receiving device according to claim 4, characterized in that, The tube base (210) includes a mounting surface at one end near the housing (110), and a mounting area is provided on the mounting surface. The photodetector (220) is located in the mounting area. The support column (260) is disposed on the mounting surface and located on the periphery of the mounting area.

6. The optical receiving device according to claim 4, characterized in that, The coaxial packaged receiver (200) further includes a transition ring (250) mounted on the support post (260), and the lens (230) is mounted on the transition ring (250).

7. The optical receiving device according to claim 6, characterized in that, The transition ring (250) and the support column (260) are welded or bonded together.

8. The optical receiving device according to claim 4, characterized in that, The support column (260) and the tube base (210) are integrally formed.

9. The optical receiving device according to any one of claims 1 to 8, characterized in that, The end face of the first end (121) is not perpendicular to the axis of the housing (110).

10. An optical transmission module, characterized in that, Includes the optical receiving device as described in any one of claims 1 to 9.

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