Optical transmission device
Patent Information
- Application Number
- TW114112842
- Authority / Receiving Office
- TW · TW
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-04-02
- Publication Date
- 2026-10-16
- Estimated Expiration
- 2045-04-01
AI Technical Summary
Existing optical transmission devices experience significant light loss at the connections between optical fibers and light sources or detectors due to discontinuous interfaces, limiting their efficiency and increasing structural costs.
An optical transmission device design featuring continuous reflective layers and modules that guide light without interfaces, utilizing a substrate with optical transmission modules, each comprising a first and second reflective layer, a light-emitting diode layer, and a light-detecting area, reducing light loss through continuous reflection and guidance.
The design effectively minimizes light loss by ensuring continuous reflection and guidance between reflective layers, enhancing transmission efficiency and reducing structural costs.
Smart Images
Figure TWG2TA001080023_001 
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Abstract
Description
[Technical Field]
[0001] This invention relates to optical communication; in particular, it refers to an optical transmission device that can reduce optical loss. [Previous Technology]
[0002] As the demand for data transmission continues to grow, traditional copper wire and optical fiber technologies have gradually shown limitations, such as low transmission efficiency and high structural cost. Optical communication technology has been widely used to replace traditional copper wire or optical fiber transmission.
[0003] Generally, optical transmission devices couple one end of an optical fiber to a light source, such as a light-emitting diode (LED), to transmit light signals into the optical fiber, while the other end of the optical fiber couples to a photodiode (PD) to detect the light signals. However, light loss easily occurs when light is transmitted at the connection between the optical fiber and the LED or PD. Therefore, how to provide an optical transmission device that can reduce light loss is an urgent problem to be solved. [Summary of the Invention]
[0004] In view of the above, the object of the present invention is to provide an optical transmission device that can effectively reduce optical loss.
[0005] To achieve the above objectives, the present invention provides an optical transmission device comprising a driving element and an optical transmission element. The optical transmission element includes a substrate and a plurality of optical transmission modules. A longitudinal reference line is defined. The optical transmission modules are arranged at intervals above the substrate along the longitudinal reference line. Each optical transmission module includes a first reflective layer, a light-emitting diode layer, and a second reflective layer. The first reflective layer is formed above the substrate. The light-emitting diode layer is formed above the first reflective layer. The second reflective layer is formed above the light-emitting diode layer. A transverse reference line is defined perpendicular to the longitudinal reference line. A light-emitting area, a light-guiding area, and a light-detecting area are sequentially arranged along the transverse reference line. The light-emitting area, the light-guiding area, and the light-detecting area all have the first reflective layer, the light-emitting diode layer, and the second reflective layer. The driving element is electrically connected to each optical transmission module to drive the light-emitting area of each optical transmission module.
[0006] The effect of the present invention is that, through the design that the first reflective layer, the light-emitting diode layer and the second reflective layer of the light-emitting area, the light-guiding area and the light-detecting area are continuous and without connecting interfaces, the light emitted by the light-emitting area of each light transmission module can be reflected between the first reflective layer and the second reflective layer of each light transmission module, and guided to the light detection area through the light-guiding area of each light transmission module. In this way, the light loss generated during light transmission can be effectively reduced.
Implementation Method
[0007] To more clearly illustrate the present invention, preferred embodiments are described in detail below with reference to the accompanying drawings. Please refer to Figures 1 to 4, which show an optical transmission device 1 according to a preferred embodiment of the present invention, comprising a driving element 10, an optical transmission element 20, and a power element 30.
[0008] As shown in FIG1, the optical transmission element 20 includes a substrate 22 and a plurality of optical transmission modules 24, defining a horizontal reference line X and a vertical reference line Y that are perpendicular to each other. The optical transmission modules 24 are arranged at intervals on the substrate 22 in the direction of the vertical reference line Y. The substrate 22 may be, for example, a silicon substrate, sapphire or silicon carbide substrate.
[0009] Referring to Figure 2, the optical transmission element 20 includes a buffer layer 240, a first reflective layer 241, a light-emitting diode layer 242, and a second reflective layer 243 stacked in phase. The first reflective layer 241 is conductive. The buffer layer 240 is formed on the substrate 22. Each optical transmission module 24 is formed on the buffer layer 240. For example, the buffer layer 240 can be an undoped GaN layer. The first reflective layer 241 is formed on the buffer layer 240 and is located on the substrate 22. The first reflective layer 241 is a porous reflective layer. For example, the first reflective layer 241 can be a Bragg mirror and the porous reflective layer is formed by electrochemical etching.
[0010] The light-emitting diode layer 242 is formed above the first reflective layer 241. For example, the light-emitting diode layer 242 may comprise a silicon-doped N-type GaN sublayer, an InGaN light-emitting sublayer, and a Mg-doped P-type GaN sublayer stacked together. In another embodiment, the light-emitting diode layer 242 may comprise a vertically stacked blue diode structure, a green diode structure, and a red diode structure, wherein the blue diode structure emits blue light, the green diode structure emits green light, and the red diode structure emits red light.
[0011] The second reflective layer 243 is formed above the light-emitting diode layer 242, wherein the second reflective layer 243 covers the top and sidewalls of the light-emitting diode layer 242. The second reflective layer 243 can be a SiO2 / TiO2 dielectric material Bragg mirror or a combination of dielectric / metal / dielectric mirror. In this embodiment, a transparent conductive layer 244 is deposited between the second reflective layer 243 and the light-emitting diode layer 242. The transparent conductive layer 244 can be, for example, an ITO layer, disposed between the light-emitting diode layer 242 and the electrode 245.
[0012] As shown in Figure 3, a light-emitting region A1, a light-guiding region A2, and a light-detecting region A3 are sequentially arranged along the transverse reference line X. Each of these regions has a first reflective layer 241, a light-emitting diode layer 242, and a second reflective layer 243. The light-emitting region A1 includes a micro-resonant cavity light-emitting diode (μ-RC-LED), and the light-detecting region A3 includes a micro-resonant cavity sensor (μ-RC-PD). The length D of the light-guiding region A2 along the transverse reference line X is greater than or equal to 200 μm and less than or equal to 30 cm. A P-type electrode 245 is disposed above the transparent conductive layer 244 of the light-emitting region A1 and the light-detecting region A3. The silicon-doped N-type GaN sublayer of the light-emitting region A1 and the light-detecting region A3 is electrically connected to the N-type electrode 246.
[0013] The buffer layer 240, the first reflective layer 241, the light-emitting diode layer 242 and the second reflective layer 243 can be formed on the substrate through semiconductor processing, and the array of light transmission modules 24 can be defined. In this way, the light emitted by the light-emitting diode layer 242 of the light-emitting region A1 is reflected between the first reflective layer 241 and the second reflective layer 243, and guided to the light detection region A3 through the light guide region A2. Through the design that the first reflective layer 241, the light-emitting diode layer 242 and the second reflective layer 243 of the light-emitting region A1, the light guide region A2 and the light detection region A3 are continuous and without connecting interfaces, the light loss of the light emitted by the light-emitting diode layer 242 of the light-emitting region A1 guided to the light detection region A3 through the light guide region A2 can be greatly reduced. In this embodiment, multiple optical transmission modules 24 are used as an example. In other embodiments, there may be only one optical transmission module 24, which can still achieve the effect of guiding the light emitted by the light-emitting diode layer 242 of the light-emitting area A1 to the light-detecting area A3 through the light-conducting area A2.
[0014] Wherein, the driving element 10 is electrically connected to each of the optical transmission modules 24 to drive the light-emitting area A1 of each of the optical transmission modules 24, and the power element 30 is electrically connected to each of the optical transmission modules 24 to receive the signal output by each of the optical transmission modules 24. For example, the power element 30 may be an element including an amplifier circuit. Furthermore, in this embodiment, the driving element 10 and the power element 30 are formed on the substrate through a semiconductor process. In this way, the driving element 10, the optical transmission modules 24 and the power element 30 can be formed on the substrate 22 in one semiconductor process. In other embodiments, the optical transmission device 1 may also include a single crystal substrate. After the driving element, the optical transmission element and the power element are each fabricated, they are respectively disposed on the single crystal substrate by, for example, flip-chip packaging. The single crystal substrate may be a glass substrate or a silicon substrate. In another embodiment, the optical transmission device 1 may further include another driving element and another power element. The other driving element is electrically connected to each of the optical transmission modules 24 to drive the light detection area A3 of each of the optical transmission modules 24. The other power element is electrically connected to each of the optical transmission modules 24 to receive the signal output by each of the optical transmission modules 24. In this way, each of the optical transmission modules 24 can simultaneously perform bidirectional optical signal transmission.
[0015] To further explain, a vertical reference line Z is defined, perpendicular to one of the horizontal reference line X and the vertical reference line Y. The wavelength of the light emitted by the light-emitting diode layer 242 of the light-emitting region A1 is λ. The minimum distance L between the first reflective layer 241 and the second reflective layer 243 on the vertical reference line Z satisfies the condition that a vertical optical resonant cavity can be formed between the first reflective layer 241 and the second reflective layer 243 of the light-emitting region A1. Further explanation is needed regarding the light emitted by the light-emitting region A1. The light emitted by the light-emitting diode layer 242 has a wavelength of λ. The minimum distance L between the first reflective layer 241 and the second reflective layer 243 in the direction of the vertical reference line Z satisfies the condition (n is the optical refractive index of 242). Thus, as shown in Figure 3, the light emitted by the light-emitting diode layer 242 in the light-emitting region A1 forms an angle θ with the vertical reference line Z. The angle θ is greater than 0 degrees, which facilitates the transmission of the light emitted by the light-emitting diode layer 242 in the light-conducting region A2.
[0016] Referring to Figure 4, for example, a chip such as a GPU, CPU, or NPU processor 2, the aforementioned optical transmission device 1 chip, and a high-bandwidth memory chip 3 such as HBM can be bonded to a wafer W (e.g., an interposer) using CoWoS (Chip-on-Wafer-on-Substrate) packaging technology to form a chip-on-wafer (CoW) structure. The CoW structure is then bonded to a substrate (e.g., a printed circuit board S (PCB)) to form a CoWoS structure. In this way, the μ-RC-LED of the light-emitting area A1 can be connected to the processor chip 2 through the driving element 10, and the μ-PD of the photodetector area A3 can be connected to the high-bandwidth memory chip 3 through the power element 30 to form a complete signal output and input architecture.
[0017] In summary, by designing the first reflective layer 241, the light-emitting diode layer 242, and the second reflective layer 243 of the light-emitting area A1, the light-guiding area A2, and the light-detecting area A3 as continuous and without connecting interfaces, the light emitted by the light-emitting area A1 of each light transmission module 24 can be reflected between the first reflective layer 241 and the second reflective layer 243 of each light transmission module 24, and guided to the light-detecting area A3 through the light-guiding area A2 of each light transmission module 24. In this way, the light loss generated during light transmission can be effectively reduced.
[0018] The above description is only a preferred embodiment of the present invention. Any equivalent changes made by applying the present invention specification and the claims should be included within the patent scope of the present invention. [Simplified Explanation of the Diagram]
[0019] Figure 1 is a schematic diagram of an optical transmission device according to a preferred embodiment of the present invention. Figure 2 is a cross-sectional view of the light-emitting area A1 in Figure 1 along the AA direction. Figure 3 is a cross-sectional view of Figure 1 along the BB direction. Figure 4 is a schematic diagram of the application of the optical transmission device of the above-mentioned preferred embodiment.
Claims
1. An optical transmission device, comprising: a driving element; an optical transmission element comprising: a substrate; a plurality of optical transmission modules defining a longitudinal reference line, the optical transmission modules being arranged at intervals above the substrate along the longitudinal reference line, each optical transmission module comprising: a first reflective layer formed above the substrate; a light-emitting diode layer formed above the first reflective layer; and a second reflective layer formed above the light-emitting diode layer; wherein... A horizontal reference line is defined perpendicular to the vertical reference line. A light-emitting area, a light-guiding area, and a light-detecting area are sequentially arranged along the horizontal reference line. The light-emitting area, the light-guiding area, and the light-detecting area all have the first reflective layer, the light-emitting diode layer, and the second reflective layer. The driving element is electrically connected to each of the optical transmission modules to drive the light-emitting area of each optical transmission module.
2. The optical transmission device as claimed in claim 1 includes a single-crystal substrate, wherein the driving element and the optical transmission element are disposed on the single-crystal substrate in a flip-chip package manner, and the single-crystal substrate is a glass substrate or a silicon substrate.
3. The optical transmission device as claimed in claim 2 includes a power element electrically connected to each of the optical transmission modules to receive signals output by each of the optical transmission modules, wherein the power element is disposed on the single-crystal substrate in a flip-chip package manner.
4. The optical transmission device as claimed in claim 1, wherein the driving element is formed on the substrate.
5. The optical transmission device as claimed in claim 4, comprising a power element electrically connected to each of the optical transmission modules to receive signals output by each of the optical transmission modules, wherein the power element is formed on the substrate; and comprising another driving element and another power element respectively electrically connected to each of the optical transmission modules, thereby enabling each of the optical transmission modules to simultaneously perform bidirectional optical signal transmission.
6. The optical transmission device as claimed in claim 1, wherein the length of the light-guiding region in the direction of the transverse reference line is greater than or equal to 200 μm and less than or equal to 30 cm.
7. The optical transmission device as claimed in claim 1, wherein a vertical reference line is defined perpendicular to one of the transverse reference line and the longitudinal reference line, the wavelength of light emitted by the light-emitting diode layer of the light-emitting region is λ, and the minimum distance L between the first reflective layer and the second reflective layer on the vertical reference line satisfies an integer multiple condition.
8. The optical transmission device as claimed in claim 1, wherein a vertical reference line is defined that is perpendicular to the transverse reference line and the longitudinal reference line, the wavelength of light emitted by the light-emitting diode layer of the light-emitting region is λ, and the minimum distance L between the first reflective layer and the second reflective layer on the vertical reference line satisfies the following condition.
9. The optical transmission device as claimed in claim 1, wherein the first reflective layer is a porous reflective layer.
10. The optical transmission device as claimed in claim 1, wherein the substrate is a silicon substrate, sapphire or silicon carbide substrate.