CN114594554A - Optical module - Google Patents
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- CN114594554A CN114594554A CN202011410442.5A CN202011410442A CN114594554A CN 114594554 A CN114594554 A CN 114594554A CN 202011410442 A CN202011410442 A CN 202011410442A CN 114594554 A CN114594554 A CN 114594554A
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- 230000003287 optical effect Effects 0.000 title claims abstract description 194
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 37
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 37
- 239000010703 silicon Substances 0.000 claims abstract description 37
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- 230000007423 decrease Effects 0.000 claims abstract description 11
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- 238000004891 communication Methods 0.000 description 8
- 230000009286 beneficial effect Effects 0.000 description 5
- 230000002457 bidirectional effect Effects 0.000 description 5
- 230000010365 information processing Effects 0.000 description 5
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- 239000010931 gold Substances 0.000 description 3
- 229910052737 gold Inorganic materials 0.000 description 3
- 238000005253 cladding Methods 0.000 description 2
- 239000012792 core layer Substances 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 230000008054 signal transmission Effects 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4219—Mechanical fixtures for holding or positioning the elements relative to each other in the couplings; Alignment methods for the elements, e.g. measuring or observing methods especially used therefor
- G02B6/4236—Fixing or mounting methods of the aligned elements
- G02B6/4244—Mounting of the optical elements
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4219—Mechanical fixtures for holding or positioning the elements relative to each other in the couplings; Alignment methods for the elements, e.g. measuring or observing methods especially used therefor
- G02B6/4236—Fixing or mounting methods of the aligned elements
- G02B6/424—Mounting of the optical light guide
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- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Couplings Of Light Guides (AREA)
- Optical Integrated Circuits (AREA)
Abstract
The application discloses optical module includes: the circuit board is provided with a silicon optical chip which receives light from the laser box. The silicon optical chip comprises a plurality of optical devices connected by waveguides, in order to improve the integration density of the silicon optical chip, different optical devices may not be arranged coaxially, and the waveguides comprise: a first straight waveguide segment; a first curved waveguide segment comprising a first initial end and a first terminal end; the first initial end is connected with the first straight waveguide section, the widths of the first initial end and the first straight waveguide section are the same, and mode mismatch does not exist between the first straight waveguide section and the first curved waveguide section, so that loss is reduced. The bend radius of the first curved waveguide segment decreases gradually in a direction from the first initial end to the first terminal end, and the waveguide width of the first curved waveguide segment increases gradually to facilitate reducing bending loss. According to the method, the shape of the waveguide and the width of the waveguide are optimally designed, so that the small-size low-loss bent waveguide is realized.
Description
Technical Field
The application relates to the technical field of communication, in particular to an optical module.
Background
An optical module generally refers to an integrated module for photoelectric conversion, which can convert an optical signal into an electrical signal and convert the electrical signal into an optical signal, and plays an important role in the field of optical communication.
At present, silicon optical chips are gaining more and more attention in 100G/400G, even 800G products as the optical engine technical scheme in the optical module. With the increase of the optical capacity of 100G to 400G 800G, the number of optical channels in the silicon optical chip is multiplied, and the number of waveguides in the silicon optical chip is also multiplied. Meanwhile, due to the size limitation of the silicon optical chip, in order to realize optical connection between devices at different positions, a bent waveguide is often required to be arranged for realizing the bent arrangement of an optical channel, and meanwhile, the physical length of the optical waveguide and the size of the silicon optical chip are reduced, and the loss is reduced.
Disclosure of Invention
An optical module is provided to reduce loss of light in a curved waveguide.
In order to solve the technical problem, the embodiment of the application discloses the following technical scheme:
the embodiment of the application discloses an optical module, includes: a circuit board;
the laser box is arranged on the circuit board;
the silicon optical chip receives the light emitted by the laser box and modulates the light to form signal light;
the silicon optical chip comprises a plurality of optical devices; the optical devices are connected through a waveguide and used for transmitting light between the optical devices;
the waveguide includes: a first straight waveguide segment;
a first curved waveguide segment comprising a first initial end and a first terminal end; the first initial end is connected with the first straight waveguide segment; in a direction from a first initial end to a first terminal end, a bend radius of the first curved waveguide segment gradually decreases, and a waveguide width of the first curved waveguide segment gradually increases;
the waveguide width of the first initial end is consistent with the waveguide width of the first straight waveguide segment;
a second straight waveguide segment connected to the first terminating end that receives light from the first curved waveguide segment.
Compared with the prior art, the beneficial effects of this application do:
the application discloses optical module includes: the circuit board is provided with a silicon optical chip which receives light from the laser box. The silicon optical chip comprises a plurality of optical devices connected by waveguides, in order to improve the integration density of the silicon optical chip, different optical devices may not be arranged coaxially, and the waveguides comprise: a first straight waveguide segment; a first curved waveguide segment comprising a first initial end and a first terminal end; the first initial end is connected with the first straight waveguide section, the waveguide width of the first initial end is consistent with that of the first straight waveguide section, and mode mismatch does not exist between the first straight waveguide section and the first bent waveguide section, so that loss is reduced. The bending radius of the first curved waveguide segment is gradually reduced and the waveguide width of the first curved waveguide segment is gradually increased along the direction from the first initial end to the first terminal end; a second straight waveguide segment connected to the first termination end receiving light from the first curved waveguide segment. The bend radius inside the first curved waveguide section is gradually reduced and the waveguide width of the first curved waveguide section is gradually increased, which is beneficial to reducing the bending loss.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.
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 creative efforts.
Fig. 1 is a schematic diagram of connection relationship of an optical communication terminal;
fig. 2 is a schematic structural diagram of an optical network terminal;
fig. 3 is a schematic structural diagram of an optical module according to an embodiment of the present application;
fig. 4 is an exploded schematic structural diagram of an optical module according to an embodiment of the present disclosure;
fig. 5 is a first schematic structural diagram of a curved waveguide according to an embodiment of the present disclosure;
fig. 6 is a schematic structural diagram of a curved waveguide according to an embodiment of the present application;
fig. 7 is a schematic structural diagram three of a curved waveguide according to an embodiment of the present application.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in the present application, 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 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; in order to establish information connection between information transmission devices such as optical fibers and optical waveguides and information processing devices such as computers, interconversion between electrical signals and optical signals is required.
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 the interconnection among the optical network terminal 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 far-end server, one end of the network cable 103 is connected with local information processing equipment, and the connection between the local information processing equipment and the far-end 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 made by the optical network terminal 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.
At this point, a bidirectional signal transmission channel is established between the remote server and the local information processing device through the optical fiber, the optical module, the optical network terminal and the network cable.
Common information processing apparatuses include routers, switches, electronic computers, and the like; the optical network terminal is an upper computer of the optical module, provides data signals for the optical module, and receives the data signals from the optical module, and the common upper computer of the optical module also comprises an optical line terminal and the like.
Fig. 2 is a schematic diagram of an optical network terminal structure. As shown in fig. 2, the optical network terminal 100 has a PCB circuit board 105, and a cage 106 is disposed on a surface of the PCB 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 projection such as a fin for increasing a heat radiation area.
The optical module 200 is inserted into the optical network terminal, specifically, the electrical port of the optical module is inserted into the electrical connector inside the cage 106, and the optical port of the optical module is connected to the optical fiber 101.
The cage 106 is positioned on the circuit board, and the electrical connector on the circuit board is wrapped in the cage, so that the electrical connector is arranged in the cage; the optical module is inserted into the cage, held by the cage, and the heat generated by the optical module is conducted to the cage 106 and then diffused by the heat sink 107 on the cage.
Fig. 3 is a schematic diagram of an optical module according to an embodiment of the present invention, and fig. 4 is a schematic diagram of an optical module according to an embodiment of the present invention. As shown in fig. 3 and 4, an optical module 200 according to an embodiment of the present invention includes an upper housing 201, a lower housing 202, an unlocking member 203, a circuit board 300, and an optical transceiver;
the upper shell 201 is covered on the lower shell 202 to form a wrapping cavity with two openings; the outer contour of the wrapping cavity is generally a square body, and specifically, the lower shell comprises a main plate and two side plates which are positioned at two sides of the main plate and are perpendicular to the main plate; the upper shell comprises a cover plate, and the cover plate covers two side plates of the upper shell to form a wrapping cavity; the upper shell can also comprise two side walls which are positioned at two sides of the cover plate and are perpendicular to the cover plate, and the two side walls are combined with the two side plates to realize that the upper shell covers the lower shell.
The two openings may be two ends (204, 205) in the same direction, or two openings in different directions; one opening is an electric port 204, and a gold finger of the circuit board extends out of the electric port 204 and is inserted into an upper computer such as an optical network terminal; the other opening is an optical port 205 for external optical fiber access to connect with an optical transceiver inside the optical module; the photoelectric devices such as the circuit board 300 and the optical transceiver are positioned in the packaging cavity.
The assembly mode of combining the upper shell and the lower shell is adopted, so that the circuit board 300, the optical transceiver and other devices can be conveniently installed in the shells, and the upper shell and the lower shell form the outermost packaging protection shell of the optical module; the upper shell and the lower shell are made of metal materials generally, so that electromagnetic shielding and heat dissipation are facilitated; generally, the housing of the optical module is not made into an integral component, so that when devices such as a circuit board and the like are assembled, a positioning component, a heat dissipation component and an electromagnetic shielding component cannot be installed, and 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 component matched with the upper computer cage; the end of the unlocking component can be pulled to enable the unlocking component to move relatively 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 component of the unlocking component; by pulling the unlocking component, the clamping component of the unlocking component moves along with the unlocking component, so that the connection relation between the clamping component and the upper computer is changed, the clamping relation 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 circuit traces, electronic components (such as capacitors, resistors, triodes, and MOS transistors), and chips (such as an MCU, a laser driver chip, a limiting amplifier chip, a clock data recovery CDR, a power management chip, and a data processing chip DSP).
The circuit board connects the electrical appliances in the optical module together according to the circuit design through circuit wiring to realize the functions of power supply, electrical signal transmission, grounding and the like.
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; when the optical transceiver is positioned on the circuit board, the rigid circuit board can also provide stable bearing; the hard circuit board can also be inserted into an electric connector in the upper computer cage, and specifically, a metal pin/golden finger is formed on the surface of the tail end of one side of the hard circuit board and is used for being connected with the electric connector; these are not easily implemented with flexible circuit boards.
A flexible circuit board is also used in a part of the optical module to supplement a rigid circuit board; the flexible circuit board is generally used in combination with a rigid circuit board, for example, the rigid circuit board may be connected to the optical transceiver device through the flexible circuit board.
The silicon optical chip 400 is arranged on the circuit board 300 and electrically connected with the circuit board 300, and specifically can be wire bonding connection; the periphery of the silicon optical chip is connected to the circuit board 300 by a plurality of conductive wires, so the silicon optical chip 400 is generally disposed on the surface of the circuit board 300.
The silicon optical chip 400 receives light from the laser box 500, and further modulates the light, specifically, loads a signal on the light; the silicon optical chip 400 receives light from the fiber optic receptacle 600, and converts the optical signal into an electrical signal.
The silicon optical chip 400 is optically connected to the optical fiber receptacle 600 through an optical fiber ribbon, and the optical fiber receptacle 600 is optically connected to an optical fiber outside the optical module. The light modulated by the silicon optical chip 400 is transmitted to the optical fiber socket 600 through the optical fiber ribbon and transmitted to the external optical fiber through the optical fiber socket 600; light transmitted from the external optical fiber is transmitted to the optical fiber ribbon through the optical fiber receptacle 600 and transmitted to the silicon optical chip 400 through the optical fiber ribbon; therefore, the silicon optical chip 400 outputs light carrying data to the optical module external optical fiber or receives light carrying data from the optical module external optical fiber.
The laser box 500 and the circuit board 300 are electrically connected, and specifically, may be connected through a flexible board. The main electrical devices in the laser box 500 are laser chips; the laser chip emits light with relatively stable power, the light is not modulated and carries no information, and a high-speed signal circuit is not involved; the circuit structure of the laser box 500 is relatively simple, and the electrical connection with the circuit board 300 can be realized through a flexible board, through which the laser chip is electrically driven from the outside of the laser box 500. The laser box 500 may be disposed on the surface of the circuit board 300, or may be disposed outside the circuit board 300.
A temperature adjusting electric device such as a semiconductor refrigerator may be provided in the laser box 500 to realize temperature control for the laser chip, and the temperature adjusting electric device obtains power supply driving from the outside of the laser box 500 through a flexible board.
The laser box 500 provides light to the silicon photonics chip 400 with relatively stable optical power. The laser box 500 is connected with the silicon optical chip 400 through an optical fiber/optical fiber ribbon.
In order to reduce the chip size, a curved waveguide cannot be arranged between optical devices of which different optical devices are curved according to an optical path, so that the optical channel can be curved, and the physical length of the optical waveguide and the size of the silicon optical chip are reduced, so that the loss is reduced. To reduce the size of the silicon optical chip, the optical path is usually bent at an angle of 90 degrees or 180 degrees, and an arc-shaped bent waveguide is disposed between two linear waveguides. However, such a curved waveguide structure generates large loss, wherein on one hand, there is a mode mismatch between the arc-shaped curved waveguide and the straight waveguide, thereby generating loss; on the other hand, when the waveguide is bent due to the wave-particle duality of the light propagation, the light propagates through the waveguide and is diffused toward the waveguide boundary, and there is a loss due to the bending.
The application is provided for reducing the loss generated by the bent waveguide and improving the light utilization rate. Fig. 5 is a first structural schematic diagram of a curved waveguide according to an embodiment of the present disclosure. The two optical devices that need to be optically connected in the silicon optical chip 400 are referred to as the first optical device and the second optical device, respectively. The first optical device is linearly connected with the first straight waveguide section 401, the second optical device is linearly connected with the second straight waveguide section 402, and the curved waveguide is arranged between the first straight waveguide section 401 and the second straight waveguide section 402. The curved waveguide includes: a first curved waveguide segment 403 and a second curved waveguide segment 404, the first initial end 4031 of the first curved waveguide segment 403 being connected to the first straight waveguide segment 401, the second end of the first curved waveguide segment 403 being connected to the second end of the second curved waveguide segment 404, the first end of the second curved waveguide segment 404 being connected to the second straight waveguide segment 402. For convenience of description, in the embodiment of the present application, the first end of the first curved waveguide segment 403 is referred to as a first initial end 4031, the second end of the first curved waveguide segment 403 is referred to as a first terminated end 4032, the first end of the second curved waveguide segment 404 is referred to as a second initial end 4041, and the second end of the first curved waveguide segment 404 is referred to as a second terminated end 4042.
The first straight waveguide segment 401 and the second straight waveguide segment 402 are perpendicular to each other. Wherein the width of the first initial end 4031 is the same as the width of the first straight waveguide segment 401, and the bending radius of the first initial end 4031 is the same as that of the first straight waveguide segment 401. To reduce the losses due to mode mismatch, the bend radius of the first initial end 4031 is at a maximum, approaching infinity, when the arc length L1 of the inner radius of the first curved waveguide segment is 0. As first initial end 4031 extends toward first terminal end 4032, arc length L1 increases, the bend radius decreases, and the width of the curved waveguide increases. The first termination end 4032 makes an angle of 45 with the first straight waveguide. Accordingly, the width of the first terminating end 4032 is greater than the width of the first initial end 4031, and the width of the first terminating end 4032 is the maximum width of the first curved waveguide segment. The radius of the first terminating end 4032 is smaller than the radius of the first initial end 4031, and the radius of the first terminating end 4032 is the smallest radius of the first curved waveguide segment. In the embodiment of the present application, by setting parameters of curve functions of the inner diameter and the outer diameter of the waveguide, the radius gradually decreases with the increase of the arc length L1, and the width of the first curved waveguide segment gradually increases.
Different from the mode mismatch existing in the connection between a straight waveguide and an arc waveguide under common conditions, in the process of transmitting the optical wave from the first straight waveguide to the first curved waveguide segment, because there is no difference in angle and width between the first straight waveguide segment 401 and the first curved waveguide segment, there is no mode mismatch, so that the loss in the process of transmitting the optical wave from the first straight waveguide segment 401 to the first curved waveguide segment is reduced. On the other hand, the transmission of the light wave in the first curved waveguide segment 403 is beneficial to reducing the loss because the bending radius is gradually reduced along with the gradual increase of the arc length L1; meanwhile, the arc length L1 of the first curved waveguide section 403 is gradually increased, and the width of the curved waveguide is gradually increased, so that the optical wave is ensured to exist in the waveguide when diffusing outwards during the propagation of the first curved waveguide section 403, and the bending loss is reduced.
Generally, the width of the second terminating end 4042 is the same as the width of the first terminating end 4032 and the first curved waveband is in the same direction as the curve of the second curved waveguide segment 404. The first straight waveguide segment 401 has the same waveguide width as the second straight waveguide segment 402, and the second curved waveguide segment 404 is mirrored with the first curved waveguide segment 403 at a perpendicular to the first terminating end. The width of the second terminating end 4042 is the same as the width of the first terminating end 4032, and the second terminating end 4042 is parallel to the optical axis of the first terminating end 4032, and there is no mode mismatch when the optical wave enters the second curved waveguide segment 404 from the first curved waveguide segment 403.
Further, to reduce the loss due to mode mismatch, the second initial end 4041 has the largest bend radius, where the arc length L2 of the inner and outer diameters of the second curved waveguide segment 404 is 0. The arc length L2 increases gradually, the bend radius decreases gradually, and the width of the curved waveguide increases gradually as the second initial end 4041 extends toward the second terminal end 4042. The second terminating end 4042 makes an angle of 45 with the second straight waveguide. Thus, the width of the second terminating end 4042 is greater than the width of the second initial end 4041, and the width of the second terminating end 4042 is the maximum width of the second curved waveguide segment 404. The radius of the second terminating end 4042 is smaller than the radius of the second initial end 4041, and the radius of the second terminating end 4042 is the smallest radius of the second curved waveguide segment 404.
The width of the second initial end 4041 of the second curved waveguide segment 404 is the same as the width of the second straight waveguide segment 402, and the second initial end 4041 is connected to the second straight waveguide segment 402, reducing losses due to mode mismatch.
In order to avoid the chip size from being too large due to the large space occupied by the bent waveguide, the waveguide width of the first terminating end 4032 should be less than or equal to 2 times the waveguide width of the first straight waveguide segment, and the bending radius of the first terminating end needs to be determined according to the bending loss. Similarly, the waveguide width of the second terminating end 4042 should be less than or equal to 2 times the waveguide width of the second straight waveguide segment, and the bending radius of the second terminating end needs to be determined according to the bending loss.
It should be noted that the bending radii of the first curved waveguide segment 403 and the second curved waveguide segment 404 refer to the inner diameter of the curved waveguide segment.
Fig. 6 is a schematic structural diagram of a second curved waveguide provided in the embodiment of the present application, and as shown in fig. 6, in order to adapt to a position of an optical device in a chip, the curved waveguide further includes: a third arcuate waveguide segment 405 disposed between the first curved waveguide segment 403 and the second curved waveguide segment 404, the third arcuate waveguide segment 405 having a width that is substantially the same as the width of the first termination end 4032. Specifically, one end of the third arcuate waveguide segment 405 is connected to the first terminating end 4032, and the other end of the third arcuate waveguide segment 405 is connected to the second terminating end 4042.
At this time, the waveguide width of the first initial end 4031 is the same as the width of the first straight waveguide segment 401, the waveguide width of one end of the third arc-shaped waveguide segment 405 is the same as the width of the first terminating end 4032, the waveguide width of the second initial end 4041 is the same as the width of the second straight waveguide segment 402, and the waveguide width of the other end of the third arc-shaped waveguide segment 405 is the same as the width of the second terminating end 4042. The third arcuate waveguide segment 405 has a radius of curvature that is consistent with the radius of curvature of the first and second terminating ends 4032 and 4042.
Fig. 7 is a schematic structural diagram three of a curved waveguide according to an embodiment of the present application. As shown in fig. 7, the present application also provides another embodiment, in a case that an angle between the propagation directions of light in the first straight waveguide segment 401 and the second straight waveguide segment 402 is less than 90 °, a curved waveguide is disposed between the first straight waveguide segment 401 and the second straight waveguide segment 402, and includes: a first curved waveguide segment 403 and a trapezoidal waveguide segment 406. The first curved waveguide segment 403 is respectively provided with a first initial end 4031 and a first terminating end 4032 along the propagation direction of light, the first initial end 4031 is connected to the first straight waveguide segment 401, and the first terminating end 4032 is connected to the trapezoidal waveguide segment 406. In the propagation direction of light, the width of the waveguide in the first curved waveguide section 403 gradually increases, and the bending radius thereof gradually decreases. The first initial end 4031 is connected to the first straight waveguide section 401, and the first terminating end 4032 forms an angle with the first straight waveguide section 401, which is the same as the angles of the first straight waveguide section 401 and the second straight waveguide section 402.
One end of the trapezoidal waveguide segment is connected with the first termination end 4032, and the other end is connected with the second straight waveguide segment 402, and along the propagation direction of light, the width of the trapezoidal waveguide segment gradually decreases, and the central axis of the trapezoidal waveguide segment coincides with the central axis of the second straight waveguide segment 402. The section of the trapezoidal waveguide section along the silicon substrate plane is trapezoidal.
Further, to reduce loss, the width of one end of the trapezoid waveguide section is the same as the width of the first termination end 4032, and the width of the other end is the same as the width of the second straight waveguide section 402, which can effectively reduce loss caused by mode mismatch.
In this embodiment, during the transmission of the optical wave from the first straight waveguide to the first curved waveguide, there is no difference in angle and width between the first straight waveguide and the first curved waveguide, and there is no mode mismatch, so that the loss of the optical wave in the transmission from the first straight waveguide to the first curved waveguide section 403 is reduced. On the other hand, the transmission of the light wave in the first bending guide section is beneficial to reducing the loss because the bending radius is gradually reduced along with the gradual increase of the arc length L1; meanwhile, the arc length L1 of the first curved waveguide section 403 is gradually increased, and the width of the curved waveguide is gradually increased, so that the light wave is ensured to exist in the waveguide when diffusing outwards during the propagation of the curved section, and the bending loss is reduced. When the optical wave enters the trapezoid waveguide section at the first curved waveguide section 403, the angle and width of the waveguide are not changed, and there is no loss caused by mode mismatch.
In the embodiment of the present application, the curved waveguide structure is suitable for a strip waveguide, and may also be suitable for a ridge waveguide. As shown, the present application provides a schematic structural diagram of a strip waveguide, the waveguide structure including: substrate, waveguide core layer, cladding. The waveguide width mentioned in the embodiments of the present application actually refers to the width of the waveguide core layer. The cladding material is limited in this application and may be solid or air.
In another embodiment, when the angle between the propagation directions of light in the first straight waveguide segment 401 and the second straight waveguide segment 402 is 180 °, the propagation direction of light waves in the figure is shown in the figure. The two optical devices that need to be optically connected in the silicon optical chip 400 are referred to as the first optical device and the second optical device, respectively. The first optical device is linearly connected with the first straight waveguide section 401, the second optical device is linearly connected with the second straight waveguide section 402, and the curved waveguide is arranged between the first straight waveguide section 401 and the second straight waveguide section 402. The curved waveguide includes: a first curved waveguide segment 403 and a second curved waveguide segment 404, a first initial end 4031 connected to the first straight waveguide segment 401, a first terminating end 4032 connected to the second terminating end 4042, and a second initial end 4041 connected to the second straight waveguide segment 402. The width of the first initial end 4031 is the same as the width of the first straight waveguide segment 401, and in order to reduce the loss caused by mode mismatch, the bending radius of the first initial end 4031 is the largest, and at this time, the arc length L1 of the inner diameter of the first curved waveguide segment 403 is 0. As first initial end 4031 extends toward first terminal end 4032, arc length L1 increases, the bend radius decreases, and the width of the curved waveguide increases. The first termination end 4032 makes a 90 deg. angle with the first straight waveguide. The second curved waveguide section is arranged in mirror image with the first curved waveguide section. The arc length increases, the bend radius decreases, and the width of the curved waveguide increases as the second initial end 4041 extends toward the second terminal end 4042.
Similarly, as described above, the present application is applicable to the case where the waveguide widths of the first straight waveguide segment and the second straight waveguide segment are the same, and is also applicable to the case where the waveguide widths of the first straight waveguide segment and the second straight waveguide segment are different.
In summary, the present application provides an optical module comprising: the circuit board is provided with a silicon optical chip which receives light from the laser box. The silicon optical chip comprises a plurality of optical devices connected by waveguides, in order to improve the integration density of the silicon optical chip, different optical devices may not be arranged coaxially, and the waveguides comprise: a first straight waveguide segment; a first curved waveguide segment comprising a first initial end and a first terminal end; the first initial end is connected with the first straight waveguide section, the waveguide width of the first initial end is consistent with that of the first straight waveguide section, and mode mismatch does not exist between the first straight waveguide section and the first bent waveguide section, so that loss is reduced. The bending radius of the first curved waveguide segment is gradually reduced and the waveguide width of the first curved waveguide segment is gradually increased along the direction from the first initial end to the first terminal end; a second straight waveguide segment connected to the first termination end receiving light from the first curved waveguide segment. The bend radius inside the first curved waveguide section is gradually decreased and the waveguide width of the first curved waveguide section is gradually increased, which is beneficial for reducing the bending loss.
The method realizes the small-size low-loss curved waveguide by optimally designing the shape and the width of the waveguide, and can be used for a plurality of devices in silicon light, such as optical waveguide connection, silicon-based modulators, silicon-based micro-ring devices and the like.
Since the above embodiments are all described by referring to and combining with other embodiments, the same portions are provided between different embodiments, and the same and similar portions between the various embodiments in this specification may be referred to each other. And will not be described in detail herein.
It is noted that, in this specification, relational terms such as "first" and "second," and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a circuit structure, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such circuit structure, article, or apparatus. Without further limitation, the presence of an element identified by the phrase "comprising an … …" does not exclude the presence of other like elements in a circuit structure, article or device comprising the element.
Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure 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.
The above-described embodiments of the present application do not limit the scope of the present application.
Claims (10)
1. A light module, comprising: a circuit board;
the laser box is arranged on the circuit board;
the silicon optical chip receives the light emitted by the laser box and modulates the light to form signal light;
the silicon optical chip comprises a plurality of optical devices; the optical devices are connected through a waveguide and used for transmitting light between the optical devices;
the waveguide includes: a first straight waveguide segment;
a first curved waveguide segment comprising a first initial end and a first terminal end; the first initial end is connected with the first straight waveguide segment; in a direction from a first initial end to a first terminal end, a bend radius of the first curved waveguide segment gradually decreases, and a waveguide width of the first curved waveguide segment gradually increases;
the waveguide width of the first initial end is consistent with that of the first straight waveguide segment, and the bending radius of the first initial end is the same as that of the first straight waveguide segment;
a second straight waveguide segment connected to the first terminating end that receives light from the first curved waveguide segment.
2. The optical module of claim 1, wherein the waveguide further comprises: a second curved waveguide segment disposed between the first curved waveguide segment and the second straight waveguide segment;
the second curved waveguide segment includes: a second initial end and a second terminal end; the second terminating end is connected with the first terminating end, and the second initial end is connected with the second straight waveguide section;
in a direction from the second initial end to the second terminal end, the bend radius of the second curved waveguide segment decreases gradually, and the waveguide width of the second curved waveguide segment increases gradually.
3. The optical module of claim 2, wherein the first and second terminal ends have the same waveguide width and the first and second terminal ends have the same bend radius.
4. The optical module of claim 2, wherein the waveguide width of the first terminating end is less than or equal to 2 times the first straight waveguide segment waveguide width.
5. The optical module of claim 2, wherein the first straight waveguide segment coincides with the second straight waveguide segment in waveguide width; the first curved waveguide segment and the second curved waveguide segment are symmetrically arranged along an angular bisector of the first straight waveguide segment and the second straight waveguide segment.
6. The optical module of claim 5, wherein the first straight waveguide segment is angled 90 ° or 180 ° from the second straight waveguide segment.
7. The optical module of claim 2, wherein the waveguide further comprises: a third curved waveguide segment disposed between the first curved waveguide segment and the second curved waveguide segment;
one end of the third arc-shaped waveguide segment is the same as the waveguide width of the first termination end, and the other end of the third arc-shaped waveguide segment is the same as the waveguide width of the second termination end;
and the bending radii of the third arc-shaped waveguide segment, the first termination end and the second termination end are consistent.
8. The optical module of claim 7, wherein the waveguide width of the third arcuate waveguide segment remains uniform throughout.
9. The optical module of claim 1, wherein the waveguide further comprises: and one end of the trapezoidal waveguide section is connected with the first termination end, and the other end of the trapezoidal waveguide section is connected with the second straight waveguide section.
10. The optical module of claim 9, wherein the waveguide width at one end of the trapezoidal waveguide coincides with the waveguide width at the first termination end, and the waveguide width at the other end coincides with the waveguide width of the second straight waveguide segment.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011410442.5A CN114594554A (en) | 2020-12-04 | 2020-12-04 | Optical module |
| PCT/CN2021/117230 WO2022116619A1 (en) | 2020-12-04 | 2021-09-08 | Optical module |
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| CN202011410442.5A CN114594554A (en) | 2020-12-04 | 2020-12-04 | Optical module |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2024046331A1 (en) * | 2022-09-02 | 2024-03-07 | 华为技术有限公司 | Optical splitter, optical splitter chip, communication device, and optical distribution network |
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| WO2022116619A1 (en) | 2022-06-09 |
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