TWI842205B - Optical element - Google Patents

Abstract

An optical element including a substrate, a first insulating layer, a first optical waveguide layer, a first edge coupler and a first micro-optical element is provided. The first insulating layer is disposed on the substrate. The first optical waveguide layer is disposed on the first insulating layer, and configured to transmit a light beam. The first edge coupler is disposed on the first insulating layer, and coupled to an end of the first optical waveguide layer. The first micro-optical element is disposed on the substrate, and includes a first inclined surface. There is a first groove between the substrate, the first insulating layer, the first optical waveguide layer and the first edge coupler. The first micro-optical element is located within the first groove. The light beam is sequentially transmitted from the first optical waveguide to the first edge coupler, emitted from the first edge coupler, and reflected by the first inclined surface to an optical fiber connector.

Description

Optical components

The present invention relates to an optical element.

Data centers have an increasing demand for equipment bandwidth and speed. In recent years, the co-packaged optics (CPO) architecture has emerged. When the bandwidth of network switches enters the 51.2T generation, the fiber packaging density will encounter a bottleneck. Therefore, photonic chips must introduce wavelength division multiplexing (WDM) components to alleviate the fiber density issue.

In the past, grating couplers were widely used in the I/O couplers of optical chips, but due to their narrow optical bandwidth, they are not suitable for serial connection with wavelength division multiplexing components. On the contrary, edge couplers have a wide optical bandwidth and are suitable for serial connection with wavelength division multiplexing components, but their biggest problem is that their measurement efficiency is very low, making them difficult to introduce into mass production.

The present invention provides an optical element that can be easily measured and is therefore suitable for mass production.

An embodiment of the present invention provides an optical element, which includes a substrate, a first insulating layer, a first optical waveguide layer, a first edge coupler and a first micro-optical element. The first insulating layer is disposed on the substrate. The first optical waveguide layer is disposed on the first insulating layer and is used to transmit a light beam. The first edge coupler is disposed on the first insulating layer and is coupled to one end of the first optical waveguide layer. The first micro-optical element is disposed on the substrate and includes a first inclined surface. A first groove is provided between the substrate, the first insulating layer, the first optical waveguide layer and the first edge coupler. The first micro-optical element is located in the first groove. The light beam is sequentially transmitted from the first optical waveguide layer to the first edge coupler, emitted from the first edge coupler, and then reflected by the first inclined surface to the optical fiber connector.

Based on the above, in one embodiment of the present invention, since the optical element adopts the first edge coupler, it is suitable for serial connection with the wavelength division multiplexing element. Moreover, the optical element is provided with a first micro-optical element, and the light beam is coupled to the optical fiber connector by using the first micro-optical element. Therefore, the optical element of the embodiment of the present invention effectively solves the problem of low wafer-level measurement efficiency and contributes to the mass production of the overall system.

10, 10A, 10B, 10C, 10D, 10E, 10F: Optical components

100: Base

200: First insulation layer

200’: Second insulating layer

300: First optical waveguide layer

400: First edge coupler

400’: Second edge coupler

500, 500A, 500D, 500E: The first micro-optical component

500’: Second micro-optical element

500S1: First slope

500S1’: The third slope

500S2: Bottom

500S3: Second slope

500S4: vertical surface

520:Metal layer

600: Cantilever structure

700: Lens

A: Air gap

d, S: distance

D: Diameter

t: thickness

F: Fiber optic connector

G: First groove

G’: Second groove

H: Height

L: Length

L1: beam

P1: bottom position

P2: Bottom

W2: Width

θ: angle of intersection

Figure 1 is a schematic diagram of an optical element according to the first embodiment of the present invention.

Figure 2 is an enlarged schematic diagram of the first micro-optical element in Figure 1.

Figure 3 is a schematic diagram of an optical element according to the second embodiment of the present invention.

Figure 4 is a schematic diagram of an optical element according to the third embodiment of the present invention.

FIG5A is a schematic diagram of an optical element according to the fourth embodiment of the present invention.

Figure 5B is an enlarged schematic diagram of Figure 5A at the lens.

Figure 6 is a schematic diagram of an optical element according to the fifth embodiment of the present invention.

FIG7 is a schematic diagram of an optical element according to the sixth embodiment of the present invention.

FIG8 is a schematic diagram of an optical element according to the seventh embodiment of the present invention.

FIG1 is a schematic diagram of an optical element according to a first embodiment of the present invention. Referring to FIG1 , an embodiment of the present invention provides an optical element 10, which includes a substrate 100, a first insulating layer 200, a first optical waveguide layer 300, a first edge coupler 400, and a first micro-optical element 500. The first insulating layer 200 is disposed on the substrate 100. The first optical waveguide layer 300 is disposed on the first insulating layer 200 and is used to transmit the light beam L1. The first edge coupler 400 is disposed on the first insulating layer 200 and is coupled to one end of the first optical waveguide layer 300. The first micro-optical element 500 is disposed on the substrate 100 and includes a first inclined surface 500S1. A first groove G is provided between the substrate 100, the first insulating layer 200, the first optical waveguide layer 300 and the first edge coupler 400. The first micro-optical element 500 is located in the first groove G. The light beam L1 is sequentially transmitted from the first optical waveguide layer 300 to the first edge coupler 400, emitted from the first edge coupler 400, and then reflected by the first inclined surface 500S1 to the optical fiber connector F. In one embodiment, the light beam L1 can also be sequentially transmitted from the optical fiber connector F to the first inclined surface 500S1, reflected by the first inclined surface 500S1 to the first edge coupler 400, and transmitted from the first edge coupler 400 to the first optical waveguide layer 300.

Specifically, the first groove G is formed by, for example, deep etching the edges of the first edge coupler 400, the first optical waveguide layer 300, and the first insulating layer 200. The first micro-optical element 500 is formed by, for example, wet etching a semiconductor material (such as silicon (Si), silicon nitride (SiN), silicon oxynitride (SiON), etc.) or metal to form a micro-optical element with a first inclined surface 500S1, and then using a flip chip bonder or other methods to package it in the first groove G with high precision. Alternatively, the material of the first micro-optical element 500 is, for example, polymer, and the micro-optical element with a first inclined surface 500S1 is formed by 3D printing technology. Then, it is packaged in the first groove G with high precision by a pick-and-place method or other methods. In another embodiment, the first micro-optical element 500 may also be a mixed structure of materials such as silicon, silicon nitride, silicon oxynitride, polymer, metal, etc., and the refractive index is preferably within the range of 1.45 to 3.5, but the present invention is not limited thereto.

In this embodiment, a reflective metal layer 520 is plated on the first inclined surface 500S1, so that the light beam L1 can be reflected by the first inclined surface 500S1.

In this embodiment, the first micro-optical element 500 further includes a bottom surface 500S2. The bottom surface 500S2 is connected to the first inclined surface 500S1. The first micro-optical element 500 is connected to the substrate 100 through the bottom surface 500S2. The angle θ between the first inclined surface 500S1 and the bottom surface 500S2 falls within the range of 30 degrees to 60 degrees.

In this embodiment, there is an air gap A between the first micro-optical element 500 and the first edge coupler 400. Since it is not desirable for the transmission distance of the light beam L1 in the air to be too long, the distance d between the first micro-optical element 500 and the first edge coupler 400 falls within the range of 0.5 micrometers (μm) to 10 μm.

FIG2 is an enlarged schematic diagram of the first micro-optical element in FIG1. Please refer to FIG1 and FIG2 simultaneously. In this embodiment, the length L of the first micro-optical element 500 perpendicular to the transmission direction of the light beam L1 in the first optical waveguide layer 300 and perpendicular to the direction from the substrate 100 to the first optical waveguide layer 300 falls within the range of 10 micrometers to 1 millimeter (mm). The first micro-optical element 500 is disposed beside the first edge coupler 400. The function of the inclined surface 500S1 is to reflect the light beam L1, turn the light beam L1 upward, and transmit it toward the optical fiber connector F. The geometric structure length L of the first micro-optical element 500 falls within the range of 10 micrometers ( μm ) to 1 millimeter (mm).

In this embodiment, the width W2 of the first micro-optical element 500 along the transmission direction of the light beam L1 in the first optical waveguide layer 300 falls within the range of 5 microns to 125 microns.

In this embodiment, the height H of the first micro-optical element 500 in the direction from the substrate 100 to the first optical waveguide layer 300 falls within the range of 1 micron to 62.5 microns.

Based on the above, in one embodiment of the present invention, since the optical element 10 uses the first edge coupler 400, it is suitable for serial connection with a wavelength division multiplexing element. Moreover, the optical element 10 is provided with a first micro-optical element 500, and the light beam L1 is coupled to the optical fiber connector F by using the first micro-optical element 500. Therefore, compared with the traditional optical element using edge couplers, which requires wafer cutting to measure the optical chip, the optical element 10 of the embodiment of the present invention effectively solves the problem of low wafer-level measurement efficiency and is conducive to the mass production of the overall system.

In addition, the manufacturing process of the micro-optical element 500 can not only use the etching process to directly form the inclined surface 500S1 on the optical element 10, but also adopt a packaging method (such as flip-chip bonder) to integrate the micro-optical element 500 on the side of the edge coupler 400 to form a 45-degree reflective inclined surface 500S1, which has several advantages: (1) The geometric structure of the micro-optical element 500 is highly flexible (such as Figures 3, 4, 5A, 5B, 6, and 7); (2) It is not necessary to use acid or alkaline solution to wet-etch the reflective inclined surface 500S1, and the process is relatively simple; (3) The bonding temperature between the micro-optical element 500 and the bottom surface 500S2 is low (such as PDMS bonding). 80~100 degrees C), will not affect other components that have been completed in the previous process (Note: The thermal budget of the general CMOS back-end process is about below 400 degrees C).

FIG3 is a schematic diagram of an optical element according to a second embodiment of the present invention. Referring to FIG3 , the optical element 10A is substantially the same as the optical element 10 of FIG1 , and the main differences are as follows. In this embodiment, the first micro-optical element 500A further includes a second inclined surface 500S3. The second inclined surface 500S3 is opposite to the first inclined surface 500S1 and faces the substrate 100. The second inclined surface 500S3 helps to align the first micro-optical element 500A with the first groove G during the placement process of the first micro-optical element 500A, so that the first micro-optical element 500A automatically slides into the first groove G.

In this embodiment, in the direction from the first optical waveguide layer 300 to the substrate 100, the bottom position P1 of the first inclined surface 500S1 is lower than the bottom P2 of the first optical waveguide layer 300, which helps to improve the optical coupling efficiency of the light beam L1 from the first edge coupler 400 to the first inclined surface 500S1.

In addition, in this embodiment, a reflective metal layer 520 is coated on the first inclined surface 500S1, so that the light beam L1 can be reflected by the first inclined surface 500S1. The remaining advantages of the optical element 10A are similar to those of the optical element 10, which will not be elaborated here.

FIG4 is a schematic diagram of an optical element according to a third embodiment of the present invention. Referring to FIG4 , the optical element 10B is substantially the same as the optical element 10A of FIG3 , and the main differences are as follows. In this embodiment, the optical element 10B further includes a cantilever structure 600. The cantilever structure 600 is connected to the first micro-optical element 500A. In another embodiment, the cantilever structure 600 can be formed integrally with the first micro-optical element 500A. The cantilever structure 600 is used to support the first edge coupler 400, so that the bottom position of the first inclined surface 500S1 is lower than the bottom of the first optical waveguide layer 300, thereby improving the optical coupling efficiency of the light beam L1 from the first edge coupler 400 to the first inclined surface 500S1. For example, when the first groove G is too deep after the etching process, the height of the first slope 500S1 will be too low, which will affect the light coupling efficiency of the optical element. Therefore, the cantilever structure 600 can avoid the problem of the first groove G being too deep.

In addition, in this embodiment, a reflective metal layer 520 is coated on the first inclined surface 500S1, so that the light beam L1 can be reflected by the first inclined surface 500S1. The remaining advantages of the optical element 10B are similar to those of the optical element 10A, which will not be elaborated here.

FIG. 5A is a schematic diagram of an optical element according to a fourth embodiment of the present invention. FIG. 5B is an enlarged schematic diagram of FIG. 5A at the lens. Referring to FIG. 5A and FIG. 5B , the optical element 10C is substantially the same as the optical element 10B of FIG. 4 , and the main differences are as follows. In this embodiment, the optical element 10C further includes a lens 700. The lens 700 is disposed on the first inclined surface 500S1, disposed on the transmission path of the light beam L1, and is used to collimate the light beam L1. In another embodiment, the lens 700 may be formed integrally with the cantilever structure 600, or the lens 700 may be formed integrally with the cantilever structure 600 and the first micro-optical element 500A. Among them, the light beam L1 is emitted from the first edge coupler 400 and then reflected by the first inclined surface 500S1 to the lens 700, and then transmitted to the optical fiber connector F after passing through the lens 700. Alternatively, the light beam L1 is sequentially transmitted from the optical fiber connector F to the lens 700, and then transmitted to the first inclined surface 500S1 after passing through the lens 700, and then reflected by the first inclined surface 500S1 to the first edge coupler 400.

In this embodiment, the diameter D of the lens 700 preferably corresponds to the diameter of the optical fiber connector F, for example, it falls between the diameters of a single-mode optical fiber connector and a multi-mode optical fiber connector. In one embodiment, the diameter D of the lens 700 falls within the range of 8 microns to 62.5 microns.

In this embodiment, the distance S between the overlapping area of the lens 700 and the first edge coupler 400 falls within the range of 0 micrometers to D/2. The thickness t of the lens 700 falls within the range of 50 micrometers to 1 millimeter. Since the optical element 10C is provided with the lens 700, it can improve the light coupling efficiency.

In addition, in this embodiment, a reflective metal layer 520 is coated on the first inclined surface 500S1, so that the light beam L1 can be reflected by the first inclined surface 500S1. The remaining advantages of the optical element 10C are similar to those of the optical element 10B and will not be elaborated here.

FIG6 is a schematic diagram of an optical element according to the fifth embodiment of the present invention. Referring to FIG6 , the optical element 10D is substantially the same as the optical element 10A of FIG3 , and the main differences are as follows. In this embodiment, the first inclined surface 500S1 and the second inclined surface 500S3 in the first micro-optical element 500D are directly connected.

In addition, in this embodiment, a reflective metal layer 520 is coated on the first inclined surface 500S1, so that the light beam L1 can be reflected by the first inclined surface 500S1. The remaining advantages of the optical element 10D are similar to those of the optical element 10A, which will not be elaborated here.

FIG. 7 is a schematic diagram of an optical element according to the sixth embodiment of the present invention. Referring to FIG. 7 , the optical element 10E is substantially the same as the optical element 10 of FIG. 1 , and the main differences are as follows. In this embodiment, the first micro-optical element 500E further includes a vertical surface 500S4. Both ends of the vertical surface 500S4 are connected to the first inclined surface 500S1 and the bottom surface 500S3, respectively.

In addition, in this embodiment, a reflective metal layer 520 is coated on the first inclined surface 500S1, so that the light beam L1 can be reflected by the first inclined surface 500S1. The remaining advantages of the optical element 10E are similar to those of the optical element 10, which will not be elaborated here.

FIG8 is a schematic diagram of an optical element according to the seventh embodiment of the present invention. Referring to FIG8 , the optical element 10F is substantially the same as the optical element 10 of FIG1 , and the main differences are as follows. In this embodiment, the optical element 10F further includes at least one second insulating layer 200′, at least one second optical waveguide layer (not shown in the figure), at least one second edge coupler 400′, and at least one second micro-optical element 500′. The second insulating layer 200′ is disposed on the substrate 100. Similar to the first optical waveguide layer 300 of FIG1 , the second optical waveguide layer is disposed on the second insulating layer 200′. The second edge coupler 400′ is disposed on the second insulating layer 200′ and is coupled to one end of the second optical waveguide (in a direction perpendicular to the paper surface of FIG6 ). The second micro-optical element 500' is disposed on the substrate 100, and the second micro-optical element 500' is located next to the first micro-optical element 500. Each second micro-optical element 500' includes a third inclined surface 500S1'. There is at least one second groove G' between the substrate 100, the second insulating layer 200', the second optical waveguide layer and the second edge coupler 400', and the second groove G' is located next to the first groove G. The second micro-optical element 500' is located in the second groove G'.

The first micro-optical element 500 and the second micro-optical elements 500' correspond to one optical fiber connector in the optical path. That is, the first micro-optical element 500 and the second micro-optical element 500' can be integrated into the optical element 10F by using a single transfer or a mass transfer, thereby improving the data throughput of the overall wafer-level measurement.

In addition, in this embodiment, the first inclined surface 500S1 and the third inclined surface 500S1' are coated with a reflective metal layer 520, so that the light beam can be reflected by the first inclined surface 500S1 or the third inclined surface 500S1'. The remaining advantages of the optical element 10F are similar to those of the optical element 10, which will not be elaborated here.

In summary, in one embodiment of the present invention, since the optical element adopts the first edge coupler, it is suitable for serial connection with the wavelength division multiplexing element. Moreover, the optical element is provided with a first micro-optical element, and the light beam is coupled to the optical fiber connector by using the first micro-optical element. Therefore, compared with the traditional optical element using edge couplers, which requires wafer cutting to measure the optical chip, the optical element of the embodiment of the present invention effectively solves the problem of low wafer-level measurement efficiency and is conducive to the mass production of the overall system.

10: Optical components

100: Base

200: First insulation layer

300: First optical waveguide layer

400: First edge coupler

500: The first micro-optical element

500S1: First slope

500S2: Bottom

520:Metal layer

A: Air gap

d: distance

F: Fiber optic connector

G: First groove

L1: beam

θ: angle of inclination

Claims (10)

An optical element includes: a substrate; a first insulating layer disposed on the substrate; a first optical waveguide layer disposed on the first insulating layer and used to transmit a light beam; a first edge coupler disposed on the first insulating layer and coupled to one end of the first optical waveguide layer; and a first micro-optical element disposed on the substrate and including a first inclined surface, wherein a first groove is provided between the substrate, the first insulating layer, the first optical waveguide layer and the first edge coupler, and the first micro-optical element is located in the first groove, wherein the light beam is sequentially transmitted from the first optical waveguide layer to the first edge coupler, emitted from the first edge coupler, and then reflected by the first inclined surface to an optical fiber connector. An optical element as described in claim 1, wherein a reflective metal layer is plated on the first inclined surface. The optical element as described in claim 1, wherein the first micro-optical element further comprises a bottom surface, the bottom surface is connected to the first inclined surface, the first micro-optical element is connected to the substrate through the bottom surface, wherein the angle between the first inclined surface and the bottom surface is in the range of 30 degrees to 60 degrees. An optical element as described in claim 1, wherein there is an air gap between the first micro-optical element and the first edge coupler. An optical element as described in claim 1, wherein the first micro-optical element further comprises a second inclined surface, the second inclined surface is opposite to the first inclined surface and faces the substrate, wherein in the direction from the first optical waveguide layer to the substrate, the bottom position of the first inclined surface is lower than the bottom of the first optical waveguide layer. An optical element as described in claim 5, wherein the first inclined surface is directly connected to the second inclined surface. An optical element as described in claim 3, wherein the first micro-optical element further includes a vertical surface, and two ends of the vertical surface are respectively connected to the first inclined surface and the bottom surface. The optical element as described in claim 1 further includes: a lens, arranged on the first inclined surface, disposed on the transmission path of the light beam, and used to collimate the light beam, wherein the light beam is reflected by the first inclined surface to the lens after being emitted from the first edge coupler. An optical element as described in claim 7, wherein the distance between the overlapping area of the lens and the first edge coupler falls within the range of 0 microns to D/2, where D is the diameter of the lens. The optical element as described in claim 1 further comprises: at least one second insulating layer disposed on the substrate; at least one second optical waveguide layer disposed on the at least one second insulating layer; at least one second edge coupler disposed on the at least one second insulating layer and coupled to one end of the at least one second optical waveguide; and at least one second micro-optical element disposed on the substrate, each second micro-optical element comprising a third inclined surface, wherein at least one second groove is provided between the substrate, the at least one second insulating layer, the at least one second optical waveguide layer and the at least one second edge coupler, and the at least one second micro-optical element is located in the at least one second groove.

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