CN115826158A

CN115826158A - Light receiving device

Info

Publication number: CN115826158A
Application number: CN202211389298.0A
Authority: CN
Inventors: 李春峰
Original assignee: Xunyun Electronic Technology Zhongshan Co ltd
Current assignee: Xunyun Electronic Technology Zhongshan Co ltd
Priority date: 2022-11-08
Filing date: 2022-11-08
Publication date: 2023-03-21

Abstract

A light receiving device includes a substrate, a light receiving chip, an optical demultiplexer, and a light transmitting member. The light receiving chip is arranged on the substrate and integrates a plurality of light detector modules and the optical waveguide structure. The optical demultiplexer is arranged on the substrate, divides the optical signals into optical signals with different wavelengths and transmits the optical signals to the optical receiving chip. The optical transfer member is optically coupled to the optical demultiplexer and provides an optical signal to the optical demultiplexer. According to the light receiving device of the embodiment of the application, the light detector module and the optical waveguide structure are integrated on the same photoelectric chip, so that the number of times of optical coupling can be reduced. Furthermore, the situation that the optical demultiplexer cracks or damages the photodetector module during the optical coupling between the light receiving chip and the optical demultiplexer can be avoided.

Description

Light receiving device

Technical Field

The present disclosure relates to a light receiving device, and more particularly, to a light receiving device in which a photodetector module and an optical waveguide structure are integrated on a same optoelectronic chip.

Background

Optical transceivers are used to transmit and receive optical signals for a variety of applications, including internet data centers, cable to the home (FTTH) applications, and the like. The optical transceiver may include an optical transmit module (TOSA) and an optical receive module (ROSA) for transmitting and receiving optical signals. When the conventional optical receiving module is assembled, the conventional optical receiving module must be optically coupled to the photodetector and the optical demultiplexer, and the coupling process is prone to cause the collision between the photodetector and the optical demultiplexer, which may cause damage and affect the reliability of the product. In addition, a gap is formed between the conventional light receiving chip and the optical demultiplexer, which affects optical coupling efficiency.

Disclosure of Invention

In view of the above, in an embodiment of the present invention, the optical detector module and the optical waveguide structure are integrated on the optical receiving chip, and then the optical coupling process is performed with the optical demultiplexer, so as to simplify the manufacturing process of the optical transceiver. And the light receiving chip is directly attached to the optical demultiplexer through the adhesion layer, so that the optical coupling efficiency is improved compared with the situation that a gap exists between the traditional light receiving chip and the optical demultiplexer.

An embodiment of the present application discloses an optical receiving device, which includes a substrate, an optical receiving chip, an optical demultiplexer, and an optical transmission member. The light receiving chip is arranged on the substrate and integrates a plurality of light detector modules and the optical waveguide structure. The optical demultiplexer is arranged on the substrate, divides the optical signals into optical signals with different wavelengths and transmits the optical signals to the optical receiving chip. The optical transfer member is optically coupled to the optical demultiplexer and provides an optical signal to the optical demultiplexer.

According to an embodiment of the present disclosure, the optical demultiplexer further includes a supporting member disposed on the substrate, the supporting member having a receiving groove, the receiving groove extending toward the optical input surface of the optical demultiplexer and aligned with the light incident portion of the optical demultiplexer.

According to an embodiment of the present application, the light transmission member includes a light receiving interface and an optical fiber cable.

According to an embodiment of the present disclosure, the optical fiber cable is disposed in the accommodating groove.

According to an embodiment of the present application, the optical fiber cable further includes a cover plate disposed on the carrier and covering a portion of the optical fiber cable.

According to an embodiment of the present disclosure, the optical waveguide structure transmits the optical signals with different wavelengths to the plurality of optical detector modules, respectively.

According to an embodiment of the present invention, the optical demultiplexer has a plurality of optical waveguide output ends, and two adjacent optical waveguide output ends have a predetermined pitch.

According to an embodiment of the present invention, the light receiving chip has a plurality of optical waveguide input ends, and two adjacent optical waveguide input ends have the predetermined pitch.

According to an embodiment of the present application, the number of the optical waveguide input ends is the same as that of the optical waveguide output ends.

According to an embodiment of the present invention, when the optical demultiplexer is optically coupled to the light receiving chip, the input end of the optical waveguide is directly aligned with the output end of the optical waveguide.

According to the light receiving device of the embodiment of the application, the light detector module and the optical waveguide structure are integrated on the same photoelectric chip, so that the number of times of optical coupling can be reduced. Moreover, the situation that the optical demultiplexer cracks or damages the photodetector module during the coupling process between the optical receiving chip and the optical demultiplexer can be avoided, and the tight junction between the optical waveguide output end of the optical demultiplexer and the optical waveguide input end of the optical receiving chip can improve the optical coupling efficiency compared with the situation that a gap exists between the conventional optical receiving chip and the optical demultiplexer. Through the design described in the embodiments of the present application, the assembly is more compact due to the high integration of the optoelectronic chip, the optical coupling efficiency can be further improved, and the complexity and the assembly efficiency of the product can be effectively simplified.

Drawings

Fig. 1A is a block diagram of a light emitting device according to an embodiment of the present application.

Fig. 1B is a block diagram of a light receiving device according to an embodiment of the present application.

Fig. 2 is an external view of a light receiving device according to an embodiment of the present application.

Fig. 3A is a schematic diagram illustrating an appearance of a light exiting surface of the optical demultiplexer 36 according to an embodiment of the present application.

Fig. 3B is an external view of the light incident surface of the light receiving chip 30 according to an embodiment of the present disclosure.

Description of the main elements

10A: light emitting module

10B: optical receiving module

11A: light emission interface

11B: optical receiving interface

12A: optical multiplexer

12B, 36: optical demultiplexer

14A: laser module

14B: photodetector module

16A: transmission processing circuit

16B: receiving processing circuit

20: substrate board

22: optical receiving interface

24: optical fiber cable

26: bearing part

27: containing groove

28: cover plate

30: light receiving chip

32: joint terminal

38: optical waveguide output

39: optical waveguide input

RX _ D1, RX _ D2, RX _ D3, RX _ D4, TX _ D1, TX _ D2, TX _ D3, TX _ D4: electrical data signal

L1, L2: optical signal

The following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

The invention will be described in further detail with reference to the following figures and examples in order to facilitate the understanding and practice of the invention for those skilled in the art, it being understood that the invention provides many applicable inventive concepts which can be embodied in a wide variety of specific forms. Those of skill in the art may now make use of the details of these and other embodiments and the various structural, logical, and electrical changes that may be made without departing from the spirit and scope of the present invention.

The present description provides various examples to illustrate the technical features of various embodiments of the present invention. The arrangement of the elements in the embodiments is for illustration and not for limiting the invention. And the reference numbers in the drawings are partially repeated in the embodiments to simplify the description, and do not indicate any relationship between the different embodiments. Wherein like element numbers used in the figures and description indicate like or similar elements. The illustrations of the present specification are in simplified form and are not drawn to precise scale. For clarity and ease of description, directional terms (e.g., top, bottom, up, down, and diagonal) are used with respect to the accompanying drawings. The following description is intended to illustrate but not limit the scope of the invention, unless otherwise indicated by the scope of the claims appended hereto.

Further, in describing some embodiments of the present application, the specification may have presented the method and/or process of the present application as a particular sequence of steps. However, the methods and procedures are not necessarily limited to the particular order of steps described, as such may not necessarily be performed according to the particular order of steps described. One skilled in the art will recognize that other sequences are possible embodiments. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claimed subject matter. Moreover, the claimed method and/or process is not limited by the order of steps, and those skilled in the art can understand that the order of steps can be modified without departing from the spirit and scope of the invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following embodiments, features of the embodiments may be combined with each other without conflict.

Fig. 1A is a block diagram of a light emitting device according to an embodiment of the present application. According to an embodiment of the present application, the light emitting apparatus includes a light emitting interface 11A and a Transmitter Optical Subassembly (TOSA) 10A. The optical transmit module 10A includes a transmit processing circuit 16A, a laser module 14A, and an optical multiplexer 12A. The light emitting device is connected to the optical fiber cable through the light emitting interface 11A. Fig. 1B is a block diagram of a light receiving device according to an embodiment of the present application. According to the embodiment of the present application, the light receiving apparatus includes a light receiving interface 11B and a Receiver Optical Subassembly (ROSA) 10B. The light receiving block 10B includes an optical demultiplexer 12B, a photodetector block 14B, and a reception processing circuit 16B. The light receiving device is connected to the optical fiber cable through the light receiving interface 11B. In the present embodiment, the light emitting interface 11A and the light receiving interface 11B may be in the form of ST type, SC type, FC type, LC type, and the like.

Dense Wavelength Division Multiplexing (DWDM) technology utilizes the bandwidth and low-loss characteristics of single-mode optical fiber, and adopts multiple wavelengths as carriers, allowing each carrier channel to be transmitted simultaneously in the optical fiber. In an embodiment of the present application, by using the dense wavelength division multiplexing technology, the optical module apparatus can receive or transmit four channels by using four different channel wavelengths (λ 1, λ 2, λ 3, λ 4), so that the optical signal L1 transmitted by the optical transmitting interface 11A can have four wavelengths of λ 1, λ 2, λ 3, λ 4, etc., and the optical signal L2 received by the optical receiving interface 11B can have four wavelengths of λ 1, λ 2, λ 3, λ 4, etc., and the number of the optical detection components of the optical detector module 14B and the number of the laser components of the laser module 14A are also configured corresponding to the number of the channels. Although this embodiment is illustrated with four channel configurations, other channel configurations (e.g., 2, 8, 16, 32, etc.) are within the scope of the present application.

Referring to fig. 1A, the electrical data signals (TX _ D1 to TX _ D4) received by the transmission processing circuit 16A are converted and output to the laser module 14A, and the laser module 14A modulates the received electrical data signals into optical signals respectively. The Laser module 14A may include one or more Vertical Cavity Surface Emitting Laser diodes (VCSELs), or Surface Emitting Laser diodes, which are arrayed and driven by a driving chip to emit optical signals. In other embodiments, other components that can be used as a light source, such as a Light Emitting Diode (LED), an Edge Emitting Laser Diode (EELD), a Distributed Feedback Laser (DFB) Laser with a diffraction grating, or an electro-absorption Modulated Laser (EML) Laser Diode package, can also be used. The optical multiplexer 12A converts the modulated optical signals corresponding to the electrical data signals (TX _ D1 to TX _ D4) into an optical signal L1 including four wavelengths of λ 1, λ 2, λ 3, λ 4, etc., and transmits to the optical transmission interface 11A to output to the optical fiber cable.

Referring to fig. 1B, the optical signal L2 is transmitted to the optical demultiplexer 12B through the optical receiving interface 11B, and according to the embodiment of the present disclosure, the optical demultiplexer 12B divides the optical signal L2 into optical signals corresponding to four wavelengths, i.e., λ 1, λ 2, λ 3, λ 4, by using an Arrayed Waveguide Grating (AWG) technology. The photo-detector modules 14B (four in this embodiment) detect the optical signals and generate corresponding electrical signals, and according to this embodiment, the photo-detector modules 14B may include PIN-in-diode (PIN-N) diodes or Avalanche Photo Diodes (APDs). The electrical signal generated by the photo-detector module 14B is processed by an amplifying circuit (e.g., trans-impedance amplifier (TIA)) and a converting circuit of the receiving processing circuit 16B, so as to obtain electrical data signals (e.g., RX _ D1 to RX _ D4) transmitted by the optical signal L2. According to other embodiments of the present application, the optical demultiplexer 12B may also use a Thin-film filter (TFF) and a Fiber Grating (FBG) to convert the optical signal L2 into optical signals with different wavelengths.

According to the embodiment of the present application, the optical transmitter module 10A and the optical receiver module 10B further include other functional circuit elements, such as a laser driver for driving the laser module 14A, A Power Controller (APC), a monitoring optical Diode (MPD) for monitoring laser Power, other circuit elements necessary for implementing an optical signal transmitting function and receiving an optical signal and processing the optical signal, and a digital signal processing integrated circuit for processing an electrical signal transmitted from the optical receiver module 10B and an electrical signal to be transmitted to the optical transmitter module 10A, which are well known in the art and will not be described herein again for brevity.

Fig. 2 is an external view of a light receiving device according to an embodiment of the present application. As shown in fig. 2, the light receiving device according to an embodiment of the present application is a silicon optical module package, and includes a substrate 20, a light receiving chip 30, an optical demultiplexer 36, and an optical transmission member. The light delivery member includes a light receiving interface 22 and a fiber optic cable 24. The fiber optic cable 24 is disposed on a carrier 26. According to one embodiment of the present application, the carrier 26 has receiving slots 27, and the receiving slots 27 extend toward the optical input surface of the optical demultiplexer 36 and are aligned with the optical waveguide input end of the optical demultiplexer 36. According to an embodiment of the present application, the receiving groove 27 may be a U-shaped groove or a V-shaped groove for placing the optical fiber cable 24. The optical fiber cable 24 and the receiving groove 27 can be fixed by an adhesive layer. In addition, the size of the receiving groove 27 may be designed according to the diameter of the optical fiber cable 24, and in other embodiments, the outer insulating layer of the optical fiber cable 24 disposed at the receiving groove 27 may be stripped off to reduce the size of the receiving groove 27. According to an embodiment of the present disclosure, a cover 28 may be disposed on the carrier 26 and cover a portion of the optical fiber cable 24 to protect the optical fiber cable 24.

The light receiving interface 22 is optically coupled to the optical demultiplexer 36 through the optical fiber cable 24. The optical fiber cable 24 is used to transmit the optical signal received via the optical receiving interface 22 to the optical demultiplexer 36. The optical demultiplexer 36 separates the received optical signal into optical signals of different wavelengths, and transmits the optical signals to the optical receiving chip 30. Referring to fig. 3A, fig. 3A is a schematic diagram illustrating an appearance of a light exiting surface of the optical demultiplexer 36 according to an embodiment of the present application. As shown, the light-emitting surface of the optical demultiplexer 36 has 4 optical waveguide output ends 38, two adjacent optical waveguide output ends 38 have the same space, and the optical demultiplexer 36 transmits the optical signals with different wavelengths to the light-receiving chip 30 through the optical waveguide output ends 38.

Referring back to fig. 2, the light receiving chip 30 integrates a photodetector module and an optical waveguide (optical waveguide) structure through which an optical signal can be transmitted. The photodetector module may detect the optical signal and generate a corresponding electrical signal. According to an embodiment of the present invention, the light receiving chip 30 further has a plurality of bonding terminals 32, which are respectively coupled to the photo detector modules corresponding to the first channel to the fourth channel for outputting the electrical signals generated by the corresponding photo detector modules. Referring to fig. 3B, fig. 3B is an external view of the light incident surface of the light receiving chip 30 according to an embodiment of the present disclosure. As shown, the light-incident surface of the light-receiving chip 30 has 4 light waveguide input ends 39, and two adjacent light waveguide input ends 39 have the same space. Since the distance between the two adjacent optical waveguide input ends 39 of the light receiving chip 30 and the distance between the two adjacent optical waveguide output ends 38 of the optical multiplexer 36 can be controlled accurately in the process, when the distance between the two adjacent optical waveguide input ends 39 of the light receiving chip 30 is the same as the distance between the two adjacent optical waveguide output ends 38 of the optical multiplexer 36, when the light incident surface of the light receiving chip 30 and the light emitting surface of the optical multiplexer 36 are optically coupled face to face, the thickness of the light receiving chip 30 and the optical multiplexer 36 is controlled, and the 4 optical waveguide input ends 39 of the light receiving chip 30 and the 4 optical waveguide output ends 38 of the optical multiplexer 36 can be aligned accurately, so that the optical signal output by the optical waveguide output ends 38 of the optical multiplexer 36 can be transmitted to the light receiving chip 30 through the optical waveguide input ends 39 with small optical loss. According to other embodiments of the present disclosure, the relative position between the light receiving chip 30 and the optical demultiplexer 36 may be adjusted by using a pad or a carrier to align the optical waveguide input end 39 and the optical waveguide output end 38. According to the embodiment of the present application, the process complexity can be simplified by the optical coupling method in the horizontal direction compared to the conventional optical coupling method in the vertical direction.

According to an embodiment of the present disclosure, the light receiving Chip 30, the optical demultiplexer 36 and the carrier 26 may be attached to the substrate 20 through an adhesive layer, and electrical connection procedures such as Wire Bonding (Wire Bonding), tape Automated Bonding (TAB), flip Chip (FC) and the like are performed on the light receiving Chip 30. The adhesive layer may include Polyimide (PI), polyethylene Terephthalate (PET), teflon (Teflon), liquid Crystal Polymer (LCP), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl Chloride (PVC), nylon (Nylon or Polyamides), polymethyl methacrylate (PMMA), ABS plastic (acrylic-Butadiene-Styrene), phenol resin (Phenolic Resins), epoxy resin (Epoxy), polyester (Polyester), silicone (Silicone), polyurethane (Polyurethane, PU), polyamide-imide (polyamide-imide, PAI), or a combination thereof, as long as the adhesive layer has adhesive properties. The substrate 20 may be made of various materials, such as plastic, epoxy, composite, FR-4, or ceramic materials. The substrate 20 has a pre-designed interconnection structure, a printed circuit formed by screen printing, and circuit elements necessary for implementing the light signal transmitting or receiving function, which are well known to those skilled in the art and will not be described herein for brevity.

When assembling the light receiving device, the light receiving chip 30 is fixed on the coupling stage, and then the bonding terminals 32 of the light receiving chip 30 are contacted with metal probes, and at this time, the light emitting surface of the optical demultiplexer 36 is brought close to the light incident surface of the light receiving chip 30, and the 4 optical waveguide output ends 38 of the optical demultiplexer 36 are aligned with the 4 optical waveguide input ends 39 of the light receiving chip 30, and an ideal coupling position is obtained when the current reaches a maximum value according to the coupling current values of the optical signals appearing at the bonding terminals 32 corresponding to the first channel and the fourth channel. Next, the light-receiving chip 30 and the optical demultiplexer 36 are fixed by an adhesive layer, and the combined light-receiving chip 30 and the optical demultiplexer 36 are attached to the substrate 20. According to an embodiment of the present disclosure, there may be no adhesive layer between the optical waveguide output end 38 of the optical demultiplexer 36 and the optical waveguide input end 39 of the light receiving chip 30, and the optical demultiplexer 36 may be fixed to the light receiving chip 30 by bonding the area between the light output surface of the optical demultiplexer 36 and the light input surface of the light receiving chip 30 except for the optical waveguide output end 38 and the optical waveguide input end 39 through the adhesive layer.

Next, the carrier 26 is bonded to the optical demultiplexer 36 such that the accommodation groove 27 is aligned with the optical waveguide input end of the optical demultiplexer 36. When the optical fiber cable 24 is placed in the receiving cavity 27, the optical alignment procedure between the optical fiber cable 24 and the optical demultiplexer 36 can be completed because the receiving cavity 27 is aligned with the optical waveguide input end of the optical demultiplexer 36. Finally, electrical connection procedures such as Wire Bonding, tape Automated Bonding (TAB), flip Chip (FC) and the like are performed on the Bonding terminals 32 of the optical receiving Chip 30.

According to the light receiving device of the embodiment of the application, the light detector module and the optical waveguide structure are integrated on the same photoelectric chip, so that the number of times of optical coupling can be reduced. Moreover, the situation that the optical demultiplexer collides and cracks or damages the photodetector module in the optical coupling process between the light receiving chip and the optical demultiplexer can be avoided, the light receiving chip and the optical demultiplexer are directly attached through the adhesion layer, and the optical waveguide output end of the optical demultiplexer is tightly connected with the optical waveguide input end of the light receiving chip. Through the design described in the embodiments of the present application, the assembly is more compact due to the high integration of the optoelectronic chip, the optical coupling efficiency can be further improved, and the complexity and the assembly efficiency of the product can be effectively simplified.

The features of the many embodiments outlined above will enable those skilled in the art to better appreciate the scope of the present invention. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure, as those changes and modifications fall within the scope of the appended claims.

Claims

1. A light receiving device characterized by comprising:

a substrate;

a light receiving chip disposed on the substrate, the light receiving chip integrating a plurality of photodetector modules and an optical waveguide structure;

an optical demultiplexer disposed on the substrate, for dividing the optical signal into optical signals with different wavelengths, and transmitting the optical signals to the optical receiving chip; and

an optical transmission member optically coupled to the optical demultiplexer and providing the optical signal to the optical demultiplexer.

2. The light receiving device as claimed in claim 1, further comprising a carrier disposed on the substrate, wherein the carrier has a receiving groove extending toward the optical input surface of the optical demultiplexer and aligned with the light incident portion of the optical demultiplexer.

3. A light receiving device according to claim 2, wherein said light transmitting member includes a light receiving interface and a fiber optic cable.

4. The light receiving device of claim 3, wherein the optical fiber cable is disposed in the receiving groove.

5. The light-receiving device of claim 4, further comprising a cover disposed on the carrier and covering a portion of the fiber optic cable.

6. The light receiving device according to claim 1, wherein the optical waveguide structure transmits the optical signals of different wavelengths to the plurality of photodetector modules, respectively.

7. The apparatus of claim 6, wherein the optical demultiplexer has a plurality of optical waveguide outputs, and two adjacent optical waveguide outputs have a predetermined space.

8. The light receiving device of claim 7, wherein the light receiving chip has a plurality of light waveguide input ends, two adjacent light waveguide input ends have the predetermined space.

9. A light receiving device according to claim 8, wherein the number of the input ends of the optical waveguide is the same as that of the output ends of the optical waveguide.

10. The light receiving device of claim 8, wherein the input end of the optical waveguide is aligned directly with the output end of the optical waveguide when the optical demultiplexer is optically coupled to the light receiving chip.