CN112904493A

CN112904493A - Optical module

Info

Publication number: CN112904493A
Application number: CN201911221071.3A
Authority: CN
Inventors: 刘旭霞; 钟岩; 罗成双; 杨思更
Original assignee: Hisense Broadband Multimedia Technology Co Ltd
Current assignee: Hisense Broadband Multimedia Technology Co Ltd
Priority date: 2019-12-03
Filing date: 2019-12-03
Publication date: 2021-06-04

Abstract

The application provides an optical module, including: the optical fiber ribbon comprises a circuit board, an optical transmitter, an optical detector, an optical receiver, a lens component and an optical fiber ribbon; an optical fiber ribbon connecting lens assembly; the top surface of the lens component is provided with a first concave part and a second concave part, the bottom surface of the lens component comprises a first step surface, a second step surface and a third inclined surface, and the side surface of the lens component is provided with a third concave part; a first inclined plane, a second inclined plane and a third inclined plane are formed on the bottom surface of the first sunken part, a reflector is obliquely arranged in the first sunken part, and a cavity is formed among the reflector, the second inclined plane and the third inclined plane; the bottom surface of the second sunken part forms a first reflecting surface; a third lens matrix is arranged on the end face of the third recess; a first lens matrix is arranged on the first step surface, a second lens matrix is arranged on the second step surface, and a height difference exists between the first step surface and the second step. The application provides an optical module, be convenient for realize that transmitting terminal optic fibre position facula and optical receiver department facula reach the best simultaneously.

Description

Optical module

Technical Field

The application relates to the technical field of optical communication, in particular to an optical module.

Background

The optical module is mainly used for photoelectric and electro-optical conversion, an electric signal is converted into an optical signal by a transmitting end of the optical module and is transmitted out through an optical fiber, and a received optical signal is converted into an electric signal by a receiving end of the optical module. The current packaging form of the optical module mainly includes a TO (Transistor-out) package and a COB (Chip on Board) package.

In COB packaging form's optical module, optical transmitter and optical receiver paste respectively on the circuit board, and the lens subassembly covers and establishes on optical transmitter and optical receiver, and optic fibre is connected to the lens subassembly, and the optical signal that the optical transmitter transmitted transmits to optic fibre after passing through lens subassembly change direction, transmits to lens subassembly optical signal through optic fibre, transmits to optical receiver after changing the direction through the lens subassembly.

In order to focus the light beam emitted by the light emitter and the light beam received by the light receiver, a lens matrix is generally disposed on the bottom surface of the lens assembly corresponding to the light emitter and the light receiver, respectively, and the focusing of the light beam emitted by the light emitter and the focusing of the light beam received by the light receiver are achieved by using the corresponding lens matrices. And the lens component is also provided with a fiber lens matrix which is used for focusing and incidence of the light beam emitted by the light emitter to the optical fiber after passing through the lens component and focusing and incidence of the light beam transmitted to the lens component through the optical fiber to the lens component. Therefore, the technical problem to be solved by those skilled in the art needs to be solved by coordinating each lens matrix to optimize the light spot of the light beam emitted by the light emitter at the optical fiber position through the lens component and the light spot of the light beam transmitted to the lens component through the optical fiber on the light receiver at the same time.

Disclosure of Invention

The application provides an optical module, be convenient for realize that transmitting terminal optic fibre position facula and optical receiver department facula reach the best simultaneously.

The application provides an optical module, includes:

a circuit board;

the light emitter is arranged on the circuit board and used for emitting light signals;

the optical detector is arranged on the circuit board and used for receiving part of optical signals emitted by the optical emitter;

the optical receiver is arranged on the circuit board and used for receiving optical signals from the outside of the optical module;

a lens assembly covering the light emitter, the light detector and the light receiver and changing the propagation direction of the signal light beam;

an optical fiber ribbon for connecting the lens assemblies;

the top surface of the lens assembly comprises a first concave part and a second concave part, the bottom surface of the lens assembly comprises a first step surface and a second step surface, and the side surface of the lens assembly comprises a third concave part;

the bottom surface of the second concave part forms a first reflecting surface, and the first reflecting surface is used for reflecting a light beam which is transmitted to the first reflecting surface from the outside of the optical module;

a first lens matrix is arranged on the first step surface and used for converging light beams emitted by the light emitter; a second lens matrix is arranged on the second step surface and used for converging the light beam reflected by the first reflecting surface to the light receiver; a height difference exists between the first step surface and the second step surface;

a first inclined plane, a second inclined plane and a third inclined plane are formed on the bottom surface of the first sunken part, a reflector is supported and arranged on the first inclined plane, and a cavity is formed among the second inclined plane, the third inclined plane and the reflector; the second inclined plane is used for refracting and reflecting light beams from the first lens matrix, the reflector is used for reflecting the light beams refracted by the second inclined plane, and the third inclined plane is used for refracting the light beams reflected by the reflector;

and a third lens matrix is arranged on the end face of the third sunken part and used for converging the light beams refracted by the third inclined surface to the optical fiber ribbon and converging and transmitting the light beams from the optical fiber ribbon to the first reflecting surface.

In the optical module provided by the application, height difference exists between a first step surface and a second step surface on a lens component, the height difference between the first step surface and the second step surface is used as compensation of the distance from a first lens matrix to a light emitting surface of a light emitter and the distance from a second lens matrix to a light receiving surface of a light receiver, mutual restriction of a lens focal length in the first lens matrix and a lens focal length in the second lens matrix is avoided, and the fact that a light spot at the position of an optical fiber at a transmitting end and a light spot at the position of the light receiver reach the best simultaneously is facilitated.

In addition, in the optical module provided in this application, through set up first depressed part on the lens subassembly top surface, and the bottom surface of first depressed part forms first inclined plane, second inclined plane and third inclined plane and first depressed part in the slope set up the speculum, first inclined plane bearing speculum, forms the cavity between second inclined plane, third inclined plane and the speculum. And the light beam emitted by the light emitter is divided into two paths through the second inclined plane, wherein one path is refracted by the second inclined plane, transmitted to the reflector, reflected by the reflector, reaches the third inclined plane, is incident and coupled to the optical fiber ribbon through the third inclined plane and the third lens matrix, and the other path is reflected by the second inclined plane, incident to the light detector, and the light beam is received by the light detector, so that the power parameter of the light is detected, and the state of the light emitter is monitored.

Drawings

In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without any creative effort.

Fig. 1 is a schematic diagram of a connection relationship of an optical communication terminal;

FIG. 2 is a schematic diagram of an optical network unit;

fig. 3 is a schematic structural diagram of an optical module provided in an embodiment of the present application;

fig. 4 is an exploded structural schematic diagram of an optical module provided in an embodiment of the present application;

FIG. 5 is a diagram illustrating a structure of a circuit board according to an embodiment of the present invention;

FIG. 6 is a top view of a lens assembly in an embodiment of the present application;

FIG. 7 is a bottom view of a lens assembly in an embodiment of the present application;

FIG. 8 is an end view of a lens assembly in an embodiment of the present application;

fig. 9 is a first partial cross-sectional view of a light module in an embodiment of the present application;

fig. 10 is a partial sectional view of a second optical module in the embodiment of the present application;

fig. 11 is a partial sectional view of a third optical module in the embodiment of the present application;

FIG. 12 is an enlarged view of a partial cross-sectional structure at the position of a first recess in the embodiment of the present application;

FIG. 13 is a diagram illustrating the structure of the transmission path of the emitted light beam in the embodiment of the present application;

FIG. 14 is an enlarged view of a partial cross-sectional structure at the location of a second recess in an embodiment of the present application;

FIG. 15 is a schematic diagram of a transmission optical path structure of a received light beam in an embodiment of the present application;

FIG. 16 is a schematic diagram of the emission path of an optical transmitter in the embodiment of the present application;

fig. 17 is a schematic diagram of a receiving optical path of an optical receiver in the embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

One of the core links of optical fiber communication is the interconversion of optical and electrical signals. The optical fiber communication uses optical signals carrying information to transmit in information transmission equipment such as optical fibers/optical waveguides, and the information transmission with low cost and low loss can be realized by using the passive transmission characteristic of light in the optical fibers/optical waveguides; meanwhile, the information processing device such as a computer uses an electric signal, and in order to establish information connection between the information transmission device such as an optical fiber or an optical waveguide and the information processing device such as a computer, it is necessary to perform interconversion between the electric signal and the optical signal.

The optical module realizes the function of interconversion of optical signals and electrical signals in the technical field of optical fiber communication, and the interconversion of the optical signals and the electrical signals is the core function of the optical module. The optical module is electrically connected with an external upper computer through a golden finger on an internal circuit board of the optical module, and the main electrical connection comprises power supply, I2C signals, data signals, grounding and the like; the electrical connection mode realized by the gold finger has become the mainstream connection mode of the optical module industry, and on the basis of the mainstream connection mode, the definition of the pin on the gold finger forms various industry protocols/specifications.

Fig. 1 is a schematic diagram of connection relationship of an optical communication terminal. As shown in fig. 1, the connection of the optical communication terminal mainly includes interconnection among the optical network unit 100, the optical module 200, the optical fiber 101, and the network cable 103.

One end of the optical fiber 101 is connected with a remote server, one end of the network cable 103 is connected with a local information processing device, and the connection between the local information processing device and the remote server is completed by the connection between the optical fiber 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is completed by the optical network unit 100 having the optical module 200.

An optical port of the optical module 200 is externally accessed to the optical fiber 101, and establishes bidirectional optical signal connection with the optical fiber 101; an electrical port of the optical module 200 is externally connected to the optical network terminal 100, and establishes bidirectional electrical signal connection with the optical network terminal 100; the optical module realizes the interconversion of optical signals and electric signals, thereby realizing the establishment of information connection between the optical fiber and the optical network terminal; specifically, the optical signal from the optical fiber is converted into an electrical signal by the optical module and then input to the optical network terminal 100, and the electrical signal from the optical network terminal 100 is converted into an optical signal by the optical module and input to the optical fiber.

The optical network terminal is provided with an optical module interface 102, which is used for accessing an optical module 200 and establishing bidirectional electric signal connection with the optical module 200; the optical network terminal is provided with a network cable interface 104, which is used for accessing the network cable 103 and establishing bidirectional electric signal connection with the network cable 103; the optical module 200 is connected to the network cable 103 through the optical network terminal 100, specifically, the optical network terminal transmits a signal from the optical module to the network cable and transmits the signal from the network cable to the optical module, and the optical network terminal serves as an upper computer of the optical module to monitor the operation of the optical module.

To this end, the remote server establishes a bidirectional signal transmission channel with the local information processing device through the optical fiber 101, the optical module 200, the optical network unit 100, and the network cable 103.

Common information processing apparatuses include routers, switches, electronic computers, and the like; the optical network unit 100 is a host computer of the optical module 200, and provides a data signal to the optical module 200 and receives a data signal from the optical module 200, and a common host computer of the optical module 200 also includes an optical line terminal and the like.

Fig. 2 is a schematic diagram of an optical network unit structure. As shown in fig. 2, the optical network unit 100 includes a circuit board 105, and a cage 106 is disposed on a surface of the circuit board 105; an electric connector is arranged in the cage 106 and used for connecting an electric port of an optical module such as a golden finger; the cage 106 is provided with a heat sink 107, and the heat sink 107 has a convex structure such as a fin for increasing a heat radiation area.

The optical module 200 is inserted into an optical network unit, specifically, an electrical port of the optical module is inserted into an electrical connector in the cage 106, and an optical port of the optical module 200 is connected with the optical fiber 101.

The cage 106 is positioned on the circuit board, enclosing the electrical connectors on the circuit board in the cage; the optical module 200 is inserted into a cage, the optical module 200 is held by the cage, and heat generated by the optical module 200 is conducted to the cage through an optical module case and finally diffused by a heat sink 107 on the cage.

Fig. 3 is a schematic structural diagram of an optical module 200 according to an embodiment of the present disclosure, and fig. 4 is an exploded structural diagram of the optical module 200 according to the embodiment of the present disclosure. As shown in fig. 3 and 4, an optical module 200 provided in an embodiment of the present application includes an upper housing 201, a lower housing 202, an unlocking member 203, a circuit board 300, and a lens assembly 400.

The upper housing 201 is covered on the lower housing 202 to form a package cavity with two openings, and the outer contour of the package cavity is generally in a square shape. Specifically, the lower housing 202 includes a main board and two side boards located at two sides of the main board and arranged perpendicular to the main board; the upper shell 201 comprises a cover plate, and the cover plate covers two side plates of the upper shell 201 to form a wrapping cavity; the upper casing 201 may further include two side walls disposed at two sides of the cover plate and perpendicular to the cover plate, and the two side walls are combined with the two side plates to cover the upper casing 201 on the lower casing 202.

The two openings may be two ends (204, 205) in the same direction, or two openings in different directions; one of the openings is an electric port 204, a golden finger of the circuit board 300 extends out of the electric port 204 and is inserted into an upper computer such as an optical network unit, the other opening is an optical port 205 and is used for external optical fiber access to connect an optical transceiver inside the optical module 200, and photoelectric devices such as the circuit board 203 and the optical transceiver are located in a package cavity.

The upper shell 201 and the lower shell 202 are combined to facilitate the installation of devices such as the circuit board 300 and the like in the shells, and the upper shell 201 and the lower shell 202 form an outermost packaging protection shell of the optical module. The upper shell 201 and the lower shell 202 are generally made of metal materials, which is beneficial to realizing electromagnetic shielding and heat dissipation; generally, the housing of the optical module 200 is not integrated, so that when devices such as a circuit board are assembled, the positioning component, the heat dissipation structure and the electromagnetic shielding structure cannot be mounted, and the production automation is not facilitated.

The unlocking component 203 is located on the outer wall of the wrapping cavity/lower shell 202, and is used for realizing the fixed connection between the optical module and the upper computer or releasing the fixed connection between the optical module and the upper computer.

The unlocking component 203 is provided with a clamping structure matched with the upper computer cage; the end of the unlocking member 203 is pulled to make the unlocking member 203 relatively move on the surface of the outer wall; the optical module is inserted into a cage of the upper computer, and the optical module is fixed in the cage of the upper computer by a clamping structure of the unlocking component 203; by pulling the unlocking member 203, the engaging structure of the unlocking member 203 moves along with the unlocking member, and further the connection relationship between the engaging structure and the upper computer is changed, so that the engaging relationship between the optical module and the upper computer is released, and the optical module can be drawn out from the cage of the upper computer.

The circuit board 300 is provided with a light emitting chip, a driving chip of the light emitting chip, a light receiving chip, a transimpedance amplifier chip, an amplitude limiting amplifier chip, a microprocessor chip, and the like, wherein the light emitting chip and the light receiving chip are directly attached to the circuit board of the optical module, and such a configuration is referred to as COB packaging in the industry.

The circuit board 300 connects the electrical appliances in the optical module together according to the circuit design through circuit wiring to realize the electrical functions of power supply, electrical signal transmission, grounding and the like; while circuit board 300 also functions to carry the various components, such as circuit board carrying lens assembly 400.

The circuit board is generally a hard circuit board, and the hard circuit board can also realize a bearing effect due to the relatively hard material of the hard circuit board, for example, the hard circuit board can stably bear a chip; the rigid circuit board can also be inserted into an electric connector in the upper computer cage, and particularly, a metal pin/golden finger is formed on the surface of the tail end of one side of the rigid circuit board and used for being connected with the electric connector.

Fig. 5 is a schematic structural diagram of a circuit board 300 according to an embodiment of the present disclosure. As shown in fig. 5, the circuit board 300 is provided with a lens assembly 400, an optical transmitter, a laser driving chip, an optical receiver, a limiting and amplifying chip, and an optical detector (not shown) which is hidden by the lens assembly 400. The lens assembly 400 is disposed above the optical chip in a covering manner, and the lens assembly 400 and the circuit board 300 form a cavity for enclosing the optical chip such as an optical transmitter and an optical receiver. Lens assembly 400 is typically a plastic device that transmits a light beam and changes the direction of the light beam as it is transmitted. Specifically, light emitted by the light emitter enters the optical fiber after being reflected by the lens assembly, light from the optical fiber enters the light receiver after being reflected by the lens assembly, and the lens assembly not only plays a role in sealing the optical chip, but also establishes optical connection between the optical chip and the optical fiber.

High-rate data transmission requires close placement between the optical chips and their driver/matching chips to shorten the interconnections between the chips and reduce signal loss due to the interconnections, while the lens assembly 400 is housed over the optical chips, so the lens assembly 400 generally houses both the optical chips and their driver/matching chips. Therefore, the light emitter and the driving chip of the light emitter are arranged in a close distance, and the lens assembly 400 covers the light emitter and the driving chip of the light emitter; the light receiver and the transimpedance amplifier chip are arranged in close proximity, and the lens assembly 400 covers the light receiver and the transimpedance amplifier chip.

In the present embodiment, the optical fiber ribbon 500 is connected to the lens assembly 400, and light beams are output and input through the optical fiber ribbon 500. Ribbon 500 includes a plurality of optical fibers therein. Optionally, the fiber optic ribbon 500 is coupled to the lens assembly 400 via a fiber optic holder 600, the fiber optic holder 600 being adapted to hold the fiber optic ribbon 500 and couple the lens assembly 400. Optionally, the optical fibers of the fiber optic ribbon 500 are secured within the fiber optic support 600 with the end faces of the optical fibers of the fiber optic ribbon 500 flush with the end faces of the fiber optic support 600.

Fig. 6 is a top view of a lens assembly 400 provided in accordance with an embodiment of the present application. As shown in fig. 6, the lens assembly 400 provided in the embodiment of the present application is provided with a first concave portion 401, a second concave portion 402 and a third concave portion 403, the first concave portion 401 and the second concave portion 402 are disposed on the top surface of the lens assembly 400 and near the center, and the third concave portion 403 is disposed on the side surface of the lens assembly 400.

The bottom surface of the first recess 401 includes a second slope and a third slope, and the mirror 404 is placed obliquely in the first recess 401. The reflector 404 covers the second slope and the third slope, and the reflector 404 forms a cavity with the second slope and the third slope. The bottom surface of the second recess 402 forms a first reflective surface 4021.

A third lens matrix 4032 is provided on an end surface of the third recessed portion 403. Optionally, a first end surface 4031 is formed in the third recessed portion 403, and a third lens matrix 4032 is disposed on the first end surface 4031. Alternatively, the third matrix of lenses 4032 is formed directly on the first end surface 4031. In the embodiment of the present application, the third lens matrix 4032 is formed by regularly arranging a plurality of lenses for focusing a parallel light beam or converting a divergent light beam into a parallel light beam.

In the present embodiment, the third recess 403 is used for connecting optical fiber ribbons. Preferably, the end face of each optical fiber in the fiber optic ribbon is correspondingly positioned at the focal point of a corresponding lens in third lens matrix 4032. Typically, the optical fiber is provided in a column arrangement, and thus, third lens matrix 4032 is a lens matrix including a row of lenses. When the light beams are transmitted to the optical fiber ribbon through the lens assembly 400, the light beams are focused and incident to the optical fibers through the lenses in the third lens matrix 4032; when the light beams transmitted through the optical fiber ribbon are input to the lens assembly 400, the diverging light beams are converged into parallel light by the third lens matrix 4032, and the light beams converted into the parallel light are transmitted inside the lens assembly 400.

Fig. 7 is a bottom view of a lens assembly 400 provided in accordance with an embodiment of the present application. As shown in fig. 7, the bottom surface of the lens assembly 400 provided in the embodiment of the present application forms a first step surface 405 and a second step surface 406. The first step surface 405 is located in a projection area of the first concave part 401 on the bottom surface of the lens assembly 400, that is, the projection of the first concave part 401 on the bottom surface of the lens assembly 400 covers the first step surface 405; the second step surface 406 is located at a projection area of the second recess portion 402 on the bottom surface of the lens assembly 400, i.e. the projection of the second recess portion 402 on the bottom surface of the lens assembly 400 covers the second step surface 406. Preferably, the first and second step surfaces 405 and 406 are parallel to the surface of the circuit board 300, respectively. The first step surface 405 and the second step surface 406 have a height difference, that is, the first step surface 405 and the second step surface 406 form a step. Optionally, the first step surface 405 and the second step surface 406 are connected by a step transition surface 408. The step transition surface 408 may be a surface perpendicular to the first and second step surfaces 405, 406 or a surface that is non-perpendicular to the first and second step surfaces 405, 406.

Further, as shown in fig. 7, the bottom surface of the lens assembly 400 provided in the embodiment of the present application is further formed with fifth inclined surfaces 407, and the fifth inclined surfaces 407 are located at the side edges of the bottom surface 405. Optionally, the fifth ramp 407 intersects the bottom surface 405. When the lens assembly 400 is fixed to the circuit board 300, the fifth slope 407 is inclined toward the circuit board 300. The fifth slope 407 is used to arrange a fourth lens matrix.

As shown in fig. 7, a first lens matrix 4051 is disposed on the first step surface 405 and a second lens matrix 4061 is disposed on the second step surface 406. Alternatively, the first lens matrix 4051 is formed directly on the first step surface 405 and the second lens matrix 4061 is formed directly on the second step surface 406. Each of the first lens matrix 4051 and the second lens matrix 4061 is formed by a regular arrangement of a plurality of lenses for focusing a parallel light beam or converting a divergent light beam into a parallel light beam. In the embodiment of the present application, the focal lengths of the lenses in the first lens matrix 4051 and the focal lengths of the lenses in the second lens matrix 4061 may be the same or different.

Specifically, the method comprises the following steps: if the focal lengths of the lenses in the first lens matrix 4051 are the same as the focal lengths of the lenses in the second lens matrix 4061, the light emitting surface of the light emitter and the light receiving surface of the light receiver are at different heights. It is possible to compensate for the difference in height between the light emitting surface of the light emitter and the light receiving surface of the light receiver by the difference in height between the first step surface 405 and the second step surface 406. If the focal lengths of the lenses in the first lens matrix 4051 are different from the focal lengths of the lenses in the second lens matrix 4061, the heights of the light emitting surface of the light emitter and the light receiving surface of the light receiver are the same or different. It is thus achieved that the difference in focal length of the lenses in the first lens matrix 4051 and the focal length of the lenses in the second lens matrix 4061 is compensated for by the difference in height between the first step surface 405 and the second step surface 406. In this way, selection of various types of transmitters and receivers in the optical module can be facilitated.

Fig. 8 is an end view of a lens assembly 400 provided in accordance with an embodiment of the present application. Referring to fig. 7 and 8, a second end surface 4033 is further formed in the third recessed portion 403, and the second end surface 4033 and the first end surface 4031 have a height difference on the third recessed portion 403, so that a groove is formed between the first end surface 4031 and the second end surface 4033, and the third lens matrix 4032 is located in the groove. In specific use, the end faces of the optical fibers in the optical fiber ribbon are flush with the second end face 4033, and the light beams passing through the third lens matrix 4032 are transmitted in the groove and enter the optical fibers in the optical fiber ribbon. Optionally, the end face of the fiber support abuttingly contacts the second end face 4033 when the fiber optic ribbon is coupled to lens assembly 400.

The third recessed portion 403 is provided with a limiting post, and the limiting post is used for fixedly connecting the optical fiber support and assisting the optical fiber support in finding the installation and fixing position. Optionally, the limiting columns include a first limiting column 4034 and a second limiting column 4035, and the first limiting column 4034 and the second limiting column 4035 are disposed on the end surface of the third recessed portion 403. Preferably, the first 4034 and the second 4035 posts are disposed on the second end surface 4033. Specifically, the first and

second positioning columns

4034 and 4035 are respectively located on the second end surface 4033 near both ends of the first end surface 4031, for example, the first positioning column 4034 is located at the left end of the first end surface 4031, and the second positioning column 4035 is located at the right end of the second positioning column 4035. Further, when the fiber holder is coupled to the lens assembly 400, the fiber holder is snap-fit coupled to the first 4034 and the second 4035.

The bottom surface of the third recessed portion 403 includes a fourth step surface 4037, the fourth step surface 4037 is connected to the second end surface 4033, and the fourth step surface 4037 is used for supporting the fiber holder and has a guiding function during the fiber holder mounting process. First and second side surfaces are provided on both sides of the fourth step surface 4037. Preferably, the first side surface and the second side surface are perpendicular to the fourth step surface 4037. The first side surface and the second side surface can assist in limiting during fiber optic shelf installation, which helps to promote the guiding function of the fourth step surface 4037.

The bottom surface of the third recessed portion 403 further includes a third step surface 4036, and the third step surface 4036 is in contact with the first end surface 4031. The third step surface 4036 and the fourth step surface 4037 have a height difference in a direction perpendicular to the third recessed portion 403, so that when the optical fiber holder is connected with the lens assembly 400, the abutting contact area between the optical fiber holder and the second end surface 4033 can be improved, and the direct installation stability of light rays can be ensured to a certain extent.

Further, in the lens assembly 400 provided in this embodiment of the application, the side edges of the third concave portion 403 are respectively provided with the first side surface 4038 and the second side surface 4039, and the length of the first side surface 4038 and the length of the second side surface 4039 in the direction of the end surface of the third concave portion 403 are smaller than the length of the third concave portion 403 in the direction of the end surface. Both the first side 4038 and the second side 4039 are inclined from the outside of the third recess 403 toward the center of the third recess 403, so that the first side 4038 and the second side 4039 increase the opening area of the top of the third recess 403, which is more convenient for the installation of the fiber holder on the basis of not affecting the installation firmness of the fiber holder.

In an embodiment of the present application, third lens matrix 4032 includes first and second lensed fibers 4032-1 and 4032-2. First fiber lens 4032-1 is used for focusing and transmitting the parallel light beams transmitted by the optical transmitters through lens assembly 400 to the optical fiber ribbon, and second fiber lens 4032-2 is used for converting the diverging light beams transmitted in the optical fiber ribbon into parallel light to be transmitted in lens assembly 400. Preferably, the focal lengths of first and second lensed fibers 4032-1 and 4032-2 are the same.

Alternatively, lens assembly 400 is a transparent plastic part, typically manufactured using an injection molding process. The first recess portion 401, the second recess portion 402 and the third recess portion 403 can be considered as grooves formed by machining the lens assembly 400.

Fig. 9 is a partial sectional view of a light module according to an embodiment of the present invention, fig. 10 is a partial sectional view of a light module according to an embodiment of the present invention, and fig. 11 is a partial sectional view of a light module according to an embodiment of the present invention. As shown in fig. 9-11, the optical transmitter 301 and the optical receiver 303 are located below the lens assembly 400, and the lens assembly 400 covers the optical transmitter 301 and the optical receiver 303. As shown in fig. 9 to 11, the first step surface 405 is located above the optical transmitter 301, the second step surface 406 is located above the optical receiver 303, and a height difference exists between the first step surface 405 and the second step surface 406.

Fig. 12 is an enlarged schematic view of a partial cross-sectional structure of the optical module at the position of the first recess 401. As shown in fig. 12, the second inclined surface 4011 and the third inclined surface 4012 on the bottom surface of the first concave portion 401 are formed by sinking the first concave portion 401 in the direction of the bottom surface of the lens assembly 400; when the reflector 404 is disposed in the first recess 401, the reflector 404 covers the second inclined surface 4011 and the third inclined surface 4012; the second slope 4011, the third slope 4012 and the mirror 404 form a cavity. The mirror 404 is an optical device for reflecting a light beam incident thereto. Typically, the mirror 404 is fabricated from a transparent plastic or glass planar coated reflective film.

Optionally, in this embodiment of the application, the second slope 4011 and the third slope 4012 meet. As shown in fig. 12, the bottom surface of the first recess 401 further includes a first inclined surface 4013, and the first inclined surface 4013 holds the support mirror 404. Optionally, a first inclined surface 4013 is located at an end of the second inclined surface 4011, and the first inclined surface 4013 fixes one end of the supporting mirror 404. Further, the bottom surface of the first recess 401 further includes a fourth inclined surface 4014, and the fourth inclined surface 4014 also serves to support the supporting mirror 404. Optionally, a fourth inclined surface 4014 is located at an end of the third inclined surface 4012, and the fourth inclined surface 4014 fixedly supports the other end of the reflecting mirror 404. In this way, the first inclined surface 4013 and the fourth inclined surface 4014 are used to support the connecting mirror 404 together, so as to increase the supporting firmness of the mirror 404.

As shown in fig. 12, the projection of the first step surface 405 on the circuit board 300 covers the light emitter 301, and the first lens matrix 4051 is disposed on the first step surface 405. In the embodiment of the present application, the first lens matrix 4051 is formed by a regular arrangement of several lenses. Preferably, the first lens matrix 4051 is a lens matrix comprising a row of lenses, and the optical axes of the lenses in the first lens matrix 4051 are perpendicular to the light emitting surface of the light emitter 301. The light beams emitted by the light emitter 301 are incident on the first lens matrix 4051, and the first lens matrix 4051 convergently converts the divergent light beams emitted by the light emitter 301 into parallel light beams. Alternatively, the first lens matrix 4051 is formed directly on the first step surface 405. Preferably, when lens assembly 400 is assembled on circuit board 300, the focal points of the lenses in first lens matrix 4051 are located on the light emitting face of light emitter 301.

As shown in fig. 12, the fifth slope 407 is located at a side of the first step surface 405, and the fifth slope 407 intersects the first step surface 405. When the lens assembly 400 is fixed on the circuit board 300, the fifth inclined plane 407 faces the circuit board 300 and faces the light detector 302, for refracting and transmitting the light beam transmitted to the fifth inclined plane 407 to the light detector 302. Preferably, a fourth lens matrix 4071 is disposed on the fifth inclined surface 407. In the embodiment of the present application, the fourth lens matrix 4071 is formed by regularly arranging a plurality of lenses. Preferably, the fourth lens matrix 4071 is a lens matrix including a row of lenses, and the optical axes of the lenses in the fourth lens matrix 4071 pass through the light receiving surface of the light detector 302. The light beam emitted by the light emitter 301 is reflected to the fifth inclined plane 407 by the lens assembly 400, and the fourth lens matrix 4071 focuses and transmits the light beam transmitted in parallel to the fifth inclined plane 407 to the light detector 302.

The optical transmitter 301 is connected to a power supply circuit and a signal circuit on the circuit board 300, and transmits an optical signal according to the electrical signal, thereby realizing conversion from the electrical signal to the optical signal in the optical module. Optionally, the light emitter 301 is mounted on the circuit board 300. In the embodiment of the present application, the optical transmitter 301 may be a light emitting chip, such as a laser chip.

The optical detector 302 is connected to the power supply circuit and the signal circuit on the circuit board 300, and the light receiving surface of the optical detector 302 receives a part of the optical signal emitted by the optical transmitter 301 reflected by the lens assembly 400, converts the received optical signal into an electrical signal, and transmits the electrical signal to the signal circuit for monitoring the state of the optical transmitter. Specifically, the monitoring of the state of the optical transmitter 301 is realized by detecting the optical power parameter of the received light beam. In the embodiment of the present application, the light detector 302 may be a photodiode chip.

Fig. 13 is a schematic diagram of a transmission optical path structure of an emitted light beam of the light emitter 301. As shown in fig. 13, the light emitter 301 emits a diverging light beam to the first lens matrix 4051, and the first lens matrix 4051 converts the diverging light beam into a parallel light beam; the parallel light beams are transmitted to the second inclined plane 4011 in the lens assembly 400, part of the parallel light beams transmitted to the second inclined plane 4011 are refracted into a cavity formed by the second inclined plane 4011, the third inclined plane 4012 and the reflector 404, and the other part of the parallel light beams is reflected by the second inclined plane 4011, namely, the parallel light beams incident to the second inclined plane 4011 are divided into two paths; the light beam refracted into the cavity formed by the second inclined plane 4011, the third inclined plane 4012 and the reflecting mirror 404 is transmitted to the reflecting mirror 404, the reflecting mirror 404 reflects the light beam to transmit to the third inclined plane 4012, the light beam is refracted by the third inclined plane 4012, then is incident into the lens assembly 400 and is transmitted to the first end surface 4031, and the parallel light transmitted to the first optical fiber lens 4032-1 in the third lens matrix 4032 on the first end surface 4031 is refracted, converged and transmitted to the optical fiber ribbon 500; the light beam reflected by the second inclined plane 4011 is transmitted to the fifth inclined plane 407, and the fourth lens matrix 4071 on the fifth inclined plane 407 convergently transmits the parallel light transmitted thereto to the light receiving surface of the light detector 302.

Fig. 14 is an enlarged view of a partial cross-sectional structure of the optical module at the position of the second recess 402. As shown in fig. 14, the lens assembly 400 has a first reflecting surface 4021 formed at a bottom surface of the second concave portion 402, and the first reflecting surface 4021 is inclined toward the second step surface 406. The first reflecting surface 4021 is for reflecting the light beam transmitted thereto. Optionally, a reflective film is formed on the first reflective surface 4021.

As shown in fig. 14, the projection of the second step surface 406 on the circuit board 300 covers the light receiver 303, and a second lens matrix 4061 is disposed on the second step surface 406. In the embodiment of the present application, the second lens matrix 4061 is formed by a regular arrangement of several lenses. Preferably, the second lens matrix 4061 is a lens matrix including a row of lenses, and the optical axes of the lenses in the second lens matrix 4061 are perpendicular to the light receiving surface of the light receiver 303. The light beam reflected by the first reflecting surface 4021 is incident on the second lens matrix 4061, and the second lens matrix 4061 condenses and enters the parallel light beam incident thereto to the light receiving surface of the light receiver 303. Alternatively, the second lens matrix 4061 is formed directly on the second step surface 406. Preferably, when the lens assembly 400 is assembled on the circuit board 300, the focal points of the lenses in the second lens matrix 4061 are located on the light receiving surface of the light receiver 303.

Fig. 15 is a schematic diagram of a transmission optical path of the light beam received by the optical receiver 303. As shown in fig. 15, light beams output by the optical fiber ribbon 500 are transmitted to the second optical fiber lens 4032-2 in the third lens matrix 4032, the light beams output by the optical fiber ribbon 500 are divergent light, the divergent light is refracted, converged and converted into parallel light through the second optical fiber lens 4032-2, the parallel light is transmitted to the first reflection surface 4021, the parallel light is reflected by the first reflection surface 4021, the light beams reflected by the first reflection surface 4021 are transmitted to the second step surface 406, and the parallel light transmitted to the second step surface 406 is refracted, converged and transmitted to the light receiving surface of the light receiver 303 by the second lens matrix 4061 on the second step surface 406.

The optical receiver 303 is connected to the power supply circuit and the signal circuit on the circuit board 300, and the optical receiver 303 is configured to receive an optical signal from outside the optical module and generate an electrical signal. When the light receiving surface of the optical receiver 303 receives an optical signal incident through the optical fiber ribbon 500, the received optical signal is converted into an electrical signal and the electrical signal is output through the signal circuit, so that conversion from the optical signal to the electrical signal in the optical module is realized. In the embodiment of the present application, the light receiver 303 may be a light receiving chip, such as a photodiode chip.

Fig. 16 is a schematic diagram of the transmission light path of the optical transmitter, and fig. 17 is a schematic diagram of the reception light path of the optical receiver. As shown in fig. 16 and 17, the end faces of the optical fibers of ribbon 500 are positioned at the focal points of the lenses of third lens matrix 4032, and the focal length of the lenses of third lens matrix 4032 is designated as f_fiberThe light emitter 301 is located at the focal point of the lenses in the first lens matrix 4051, and the focal length of the lenses in the first lens matrix 4051 is denoted as f_TXThe spot diameter at the fiber position is denoted S₀. As shown in FIG. 16, the light emitting diameter dimension S of the light emitter 301 in the emitted light path₁The relationship between the two is S₀/S₁＝f_fiber/f_TX(1). As shown in fig. 17, in the receiving optical path, the optical receiver 303 is located at the focal position of the lenses in the second lens matrix 4061, and the focal length of the lenses in the second lens matrix 4061 is denoted as f_RX. When the optical fibers of the optical fiber ribbon 500 are filled with light, the spot size at the optical fiber location is the diameter of the optical fiber. Assuming that the diameter of the optical fiber is 50 μm, the spot S of the light received at the optical receiver 303 and the spot S of the light at the position of the optical fiber₂Has a relationship of 50/S₂＝f_fiber/f_RX(2)。

If the first lens matrix 4051 and the second lens matrix 4061 are in the same plane, when the height difference between the optical transmitter 301 and the optical receiver 303 is small, it can be assumed that f_TX≈f_RXIn this case, S can be obtained from the relational expressions (1) and (2)₀·S₂It can be known that the size of the light spot at the position of the optical fiber is in inverse proportion to the size of the light spot received by the optical receiver 303, which is restricted with each other, and the purpose of small light spot cannot be achieved at the same time, so that only one compromise size can be obtained, and both light spots can meet the use requirements. If the effective light receiving area of the light receiver is large, typically about 60 μm, in the 10G product, the light receiving spot at the light receiver 303 is largeIt may be suitably larger, for example, about 40 μm; however, in the 25G/100G product, the effective light receiving area of the light receiver 303 is small, generally about 40 μm, and in this case, the light spot received by the light receiver 303 is required to be about 20 μm. If the spot size is large, the difficulty of the chip process and the fiber coupling will increase and the efficiency will be low.

In the optical module provided by the application, S is effectively solved₀And S₂In the problem of mutual restriction, a height difference is set between the first step surface 406 where the first lens matrix 4051 is located and the second step surface 406 where the second lens matrix 4061 is located, that is, the first step surface 405 and the second step surface 406 form a step with a certain height, and the height of the step is used as compensation for the distance between the second lens matrix 4061 and the light receiver, so that f with different sizes can be designed_TX、f_RXObtaining the ideal S₀、S₂The optical receiver can be used at different heights under the condition of the same focal length, or the optical receiver and the optical transmitter can be compatible.

The calculation of the difference in height between the first step surface and the second step surface in the practice of the present application is given below:

first of all, f is determined_fiber、f_TXIn the range of (1), the numerical aperture NA of the optical fiber is 0.2, and 2 · f is a geometric relationship_fiberNA. ltoreq.D, i.e. f_fiberLess than or equal to 0.625 mm. Similarly, the divergence angle θ of the laser is 13 °, according to the geometrical relationship, 2 · f_TXTan θ ≦ D, i.e. f_TXLess than or equal to 0.541 mm. Secondly, the reasonable S is designed by comprehensively considering the optical fiber coupling efficiency and the distance relationship between the lenses and the light emitter in the first lens matrix₀、f_TXSubstituting the relation (1) to calculate f_fiberGuarantee f_TXAnd f_fiberWithin the respective ranges.

Then the S is mixed₂、f_fiberSubstituting the relation (2) to obtain f_RX. In addition, since the optical receiver is connected with the pad position wire bonding, the arc height of the wire bonding is 0.12mm, so that f is ensured_RXNot less than 0.12mm to prevent the gold thread from touching the lens surface of the second lens matrix and affecting the second lens matrixOptical properties of the lenses in the lens matrix. If the vertical distance between the lens plane and the light receiver in the first lens matrix is H, the height Δ H of the height difference between the first step surface and the second step surface is H-f_RX。

Therefore, in the optical module provided by the application, a height difference exists between the first step surface 405 and the second step surface 406 on the lens component 400, and the height difference between the first step surface 405 and the second step surface 406 is used as compensation for a distance from the first lens matrix 4051 to the light emitting surface of the optical transmitter 301 and a distance from the second lens matrix 4061 to the light receiving surface of the optical receiver 303, so that mutual restriction between a focal length of a lens in the first lens matrix 4051 and a focal length of a lens in the second lens matrix 4061 is avoided, and it is convenient to achieve that a light spot at an optical fiber position in an optical fiber ribbon at a transmitting end and a light spot at the optical receiver 303 reach the best.

All the embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments, and the relevant points may be referred to the part of the description of the method embodiment. It is noted that other embodiments of the present application will become readily apparent to those skilled in the art from consideration of the specification and practice of the invention herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.

It will be understood that the present application is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims

1. A light module, comprising:

a circuit board;

an optical fiber ribbon for connecting the lens assemblies;

2. The optical module of claim 1, wherein the focal lengths of the lenses in the first lens matrix and the focal lengths of the lenses in the second lens matrix are different, and the light emitting surface of the light emitter and the light receiving surface of the light receiver are at the same height.

3. The optical module of claim 1, wherein the focal lengths of the lenses in the first lens matrix and the focal lengths of the lenses in the second lens matrix are the same, and the light emitting surface of the light emitter and the light receiving surface of the light receiver are different in height.

4. The optical module of claim 1, wherein the focal lengths of the lenses in the first lens matrix and the focal lengths of the lenses in the second lens matrix are different, and the heights of the light emitting surface of the light emitter and the light receiving surface of the light receiver are different.

5. The optical module of claim 1, wherein the bottom surface of the lens assembly includes a fifth inclined surface, a fourth lens matrix is disposed on the fifth inclined surface, and the light beam reflected by the second inclined surface is transmitted to the fifth inclined surface and then converged to the optical detector by the fourth lens matrix.

6. The optical module of claim 1, wherein the third recess comprises a first end surface and a second end surface, the second end surface having a height difference from the first end surface;

the third lens matrix is arranged on the first end face, the second end face is provided with a first limiting column and a second limiting column, the first limiting column is located at one end of the first end face, and the second limiting column is located at the other end of the first end face.

7. The optical module of claim 6, further comprising a fiber support supporting the optical fiber ribbon, the fiber support clamping the first and second limiting posts, the optical fiber ribbon connecting the lens assembly through the fiber support.

8. The optical module of claim 6, wherein the third recess includes a third step surface and a fourth step surface, the third step surface interfacing with the first end surface, the fourth step surface interfacing with the second end surface, the fourth step surface for supporting the fiber holder.

9. The optical module of claim 1, wherein the focal point of the third lens matrix is located at an end face of an optical fiber in the optical fiber ribbon.

10. The optical module of claim 1, wherein the third lens matrix comprises a first fiber lens and a second fiber lens, the first fiber lens and the second fiber lens have the same focal length, the first fiber lens couples the light beams refracted by the third inclined surface to the optical fiber ribbon in a convergent manner, and the second fiber lens transmits the light beams from the optical fiber ribbon in a convergent manner to the first reflecting surface.