CN217766908U - Optical component integrated with three-dimensional waveguide and optical chip - Google Patents

Abstract

The embodiment of the application relates to an optical component integrating three-dimensional waveguide and an optical chip. According to some embodiments of the present application, an optical component integrating a three-dimensional waveguide, comprising: a substrate; a three-dimensional waveguide located inside the substrate; a first waveguide positioned above the substrate, wherein an end of the three-dimensional waveguide extends to a surface of the substrate and is coupled with at least a portion of the first waveguide, and an optical device coupled with the first waveguide, wherein a surface of the end of the first waveguide is tapered such that light can enter the first waveguide from the three-dimensional waveguide by evanescent coupling. Another embodiment of the present application provides an optical chip including one or more of the optical assemblies described herein. The optical component integrating the three-dimensional waveguide and the optical chip provided by the embodiment of the application can effectively solve the problems in the traditional technology.

Description

Optical component integrated with three-dimensional waveguide and optical chip

Technical Field

The application belongs to the technical field of optical communication, and particularly relates to an optical component and an optical chip integrating three-dimensional waveguide.

Background

With the continuous progress of micro-nano processing technology, the preparation method of the three-dimensional waveguide is mature day by day, and the application field of the three-dimensional waveguide is increasingly wide. At present, when the three-dimensional waveguide is coupled with the optical device, because the mode is close to the structure of the traditional vertical incident light device, the three-dimensional waveguide needs to be bent for many times so as to increase the contact area with the optical device and enhance the light absorption efficiency of the optical device, the pulse attenuation time is as long as tens of nanoseconds, and the absorption efficiency is not ideal.

Based on this, this application proposes an optical component and an optical chip integrating a three-dimensional waveguide.

SUMMERY OF THE UTILITY MODEL

The present application is made to solve the above-mentioned problems, and an object of the present application is to provide an optical component and an optical chip integrating a three-dimensional waveguide, in which an optical device is disposed at a position where light intensity extending along a direction of a first waveguide is maximum by extending the three-dimensional waveguide to a surface of a substrate and depositing and preparing the first waveguide on the surface of the substrate, so that an absorption rate of the optical device to an optical field can be significantly increased.

The present application provides an optical assembly integrating a three-dimensional waveguide, comprising:

a substrate;

a three-dimensional waveguide located inside the substrate;

a first waveguide positioned over the substrate, wherein one end of the three-dimensional waveguide extends to a surface of the substrate and is coupled to at least a portion of the first waveguide, an

An optical device coupled to the first waveguide,

wherein the surface taper at one end of the first waveguide enables light to enter the first waveguide from the three-dimensional waveguide by evanescent coupling.

The optical assembly described above wherein the optical device is located within or on a surface of the first waveguide.

In the above optical assembly, the optical device is located on a surface of the substrate, and at least a portion of the first waveguide covers at least a portion of the optical device.

In the above optical assembly, the first waveguide is deposited, grown, spin coated or bonded on the substrate by smart cut (smart cut) process.

In the above optical assembly, the first waveguide includes at least one of a silicon nitride waveguide and a silicon oxynitride waveguide.

In the above optical assembly, one end of the three-dimensional waveguide is coupled to at least a portion of one end of the first waveguide.

In the above optical assembly, the optical device is coupled to an end of the first waveguide opposite to the other end.

In the above optical assembly, a surface width of one end of the first waveguide increases to a first width along a transmission direction of light in the first waveguide.

In the above optical assembly, a surface width of one end of the first waveguide gradually increases to a first width along a transmission direction of light in the first waveguide and then gradually decreases to a second width.

The present application also provides a light chip comprising a plurality of optical assemblies according to any of the preceding claims.

Application for action and Effect

According to the present application there is provided an optical component incorporating a three-dimensional waveguide, comprising: a substrate; a three-dimensional waveguide located inside the substrate; the optical device includes a substrate, a first waveguide positioned over the substrate, wherein an end of the three-dimensional waveguide extends to a surface of the substrate and is coupled with at least a portion of the first waveguide, and an optical device coupled with the first waveguide, wherein a surface of the end of the first waveguide is tapered such that light can enter the first waveguide from the three-dimensional waveguide by evanescent coupling. Because the optical device is integrated in the first waveguide or the upper and lower surfaces with adjustable mode field diameter and binding degree, light enters the first waveguide from the three-dimensional waveguide in an evanescent wave coupling mode, and the optical device is arranged in the first waveguide or the surface, so that the interaction strength of the optical device and the mode field in the waveguide can be obviously enhanced and the light absorption efficiency of the optical device can be improved compared with the coupling with the three-dimensional waveguide with weaker mode field binding and larger mode field diameter.

Drawings

FIG. 1 is a side view of an integrated three-dimensional waveguide optical assembly according to an embodiment of the present application.

Fig. 2 is a top view of the integrated three-dimensional waveguide optical assembly of fig. 1.

Fig. 3 is a side view of an integrated three-dimensional waveguide optical assembly in another embodiment.

Fig. 4 is a side view of an integrated three-dimensional waveguide optical assembly of yet another embodiment.

Fig. 5 is a top view of the optical assembly of the integrated three-dimensional waveguide of fig. 4.

Fig. 6 is a side view of an optical assembly incorporating a three-dimensional waveguide in a further embodiment.

Detailed Description

In order to make the technical means, the technical features, the technical objectives and the functions realized by the present invention easily understood, the optical component and the optical chip integrated with the three-dimensional waveguide provided by the present invention are specifically described below with reference to the embodiments and the accompanying drawings.

Embodiments of the present application will be described in detail below. Throughout the specification, the same or similar components and components having the same or similar functions are denoted by like reference numerals. The embodiments described herein with respect to the figures are illustrative in nature, are diagrammatic in nature, and are used to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limiting the present application.

As used herein, the terms "substantially," "about," and "left-right" are used to describe and illustrate minor variations. When used in conjunction with an event or circumstance, the terms can refer to instances where the event or circumstance occurs precisely as well as instances where the event or circumstance occurs in close proximity. For example, when used in conjunction with numerical values, the term can refer to a range of variation that is less than or equal to ± 10% of the stated numerical value, such as less than or equal to ± 5%, less than or equal to ± 4%, less than or equal to ± 3%, less than or equal to ± 2%, less than or equal to ± 1%, less than or equal to ± 0.5%, less than or equal to ± 0.1%, or less than or equal to ± 0.05%. For example, two numerical values are considered to be "substantially" identical if the difference between the two numerical values is less than or equal to ± 10% (e.g., less than or equal to ± 5%, less than or equal to ± 4%, less than or equal to ± 3%, less than or equal to ± 2%, less than or equal to ± 1%, less than or equal to ± 0.5%, less than or equal to ± 0.1%, or less than or equal to ± 0.05%) of the mean of the values.

In this specification, unless specified or limited otherwise, relative terms such as: the terms "vertical," "side," "upper," "lower," and derivatives thereof (e.g., "top surface," etc.) should be construed to refer to the orientation as then described or as shown in the drawing. These relative terms are for convenience of description only and do not require that the present application be constructed or operated in a particular orientation.

Additionally, amounts, ratios, and other numerical values are sometimes presented herein in a range format. It is to be understood that such range format is used for convenience and brevity, and it is to be flexibly understood to include not only the values explicitly specified as the limits of the range, but also all the individual values or sub-ranges encompassed within that range as if each value and sub-range is explicitly specified.

Also, for convenience of description, "first," "second," etc. may be used herein to distinguish between different operations of a component or series of components. "first," "second," etc. are not intended to describe corresponding components.

< example >

Fig. 1 and 2 are side and top views of an integrated three-dimensional waveguide optical assembly 100 according to an embodiment of the present application.

As shown in fig. 1 and 2, an optical module (hereinafter referred to as an optical module) 100 integrating a three-dimensional waveguide in the present embodiment includes: a substrate 10; a three-dimensional waveguide 20; which is located inside the substrate 10; a first waveguide 30 located above the substrate 10, wherein one end of the three-dimensional waveguide 20 extends to a surface of the substrate 10 and is coupled with at least a portion of the first waveguide 30, the optical assembly 100 further comprising an optical device 40 coupled with the first waveguide 30, wherein a surface of one end 31 of the first waveguide 30 is tapered such that light (transmitted in the first waveguide 30 along direction a) can enter the first waveguide 30 from the three-dimensional waveguide 20 by evanescent coupling.

"coupling" in this application may be understood as optical coupling or mechanical coupling, such as attaching or fixing the three-dimensional waveguide and the first waveguide, or merely contacting without any fixation, and it is understood that direct coupling or indirect coupling (in other words, coupling without direct contact) may be provided.

In this application, "optical device" includes both active and passive devices, which require light to pass through, and which can control light, such as to route, modulate, generate or absorb light, and so forth.

Referring to the optical assembly 100 of the embodiments of fig. 1 and 2, the substrate 10 of the optical assembly 100 may comprise a silicon dioxide substrate, and in other embodiments, the substrate 10 may be made of other materials, such as photoresist or other low index polymers, and the three-dimensional waveguide 20 is located within the substrate 10 and may be made by modifying a predetermined area of the substrate.

The first waveguide 30 is positioned above the substrate 10, and one end of the three-dimensional waveguide 20 extends to the surface of the substrate 10. At least a portion of one end 31 of the first waveguide 30 is coupled to one end of the three-dimensional waveguide 20. First waveguide 30 may comprise a silicon nitride waveguide, and in other embodiments, first waveguide 30 may comprise other waveguides, such as a silicon oxynitride waveguide, which may be grown on a substrate by deposition.

The optical device 40 is located inside the first waveguide 30 or on the surface of the substrate 10, i.e. between the substrate and the first waveguide, and at least a part of the first waveguide 30 wraps at least a part of the optical device 40. In some embodiments, the optical device 40 may also be located at the center of the thickness of the first waveguide 30, or may also be located at the upper surface of the first waveguide 30.

Optical device 40 may include a Superconducting Nanowire Single Photon Detector (SNSPD), such as a niobium nitride SNSPD, as shown in fig. 2, where optical device 40 has a U-shaped structure with two terminals for connecting to an external circuit. In other embodiments, optical device 40 may also include other optical devices, such as a general waveguide coupled Photodetector (PD).

Integrated quantum optical devices used in applications such as photon computing require the use of single photon detectors to analyze the photon states. Compared with the conventional superconducting nanowire single-photon detector (SNSPD) with vertical incidence, a so-called waveguided-integrated SNSPD (WI-SNSPD) integrated with a waveguide has been studied more in recent years due to its advantages of high efficiency, low time jitter, and the like. In the WI-SNSPD structure, the SNPSD extends along the waveguide direction at the top of the waveguide, and the incident photons are detected by absorbing evanescent waves of a waveguide mode field. The longer the SNSPD, the higher the absorption light ratio and thus the higher the on-chip detection efficiency. However, as the length of the SNSPD increases, the inductance increases accordingly, so that the decay time of the electrical pulse formed by detecting a single photon becomes longer. Within the decay time of a pulse after one detection (absorption of one photon to generate an electric pulse), the detector cannot respond to the next absorbed photon, so that the maximum detection rate is limited by the length of SNSPD, and the shorter the SNSPD is, the faster the system responds, and the higher the operating frequency is.

The three-dimensional waveguide prepared by the femtosecond laser direct writing process has the third dimension which is more than that of the chip on the chip, so that the functions of quantum application chips such as light quantum calculation and the like can be obviously enhanced. Combining a three-dimensional waveguide with SNSPD may reduce transmission and detection losses of photons emitted from the three-dimensional waveguide. At present, the SNSPD integrated on the three-dimensional waveguide is similar to a traditional vertical incidence SNSPD structure, the integrated structure increases the contact area with the SNSPD by bending the three-dimensional waveguide for multiple times so as to increase the light absorption efficiency of the SNSPD, but the combined structure can lead the pulse attenuation time to be tens of nanoseconds, and the SNSPD light absorption efficiency is lower.

Therefore, the embodiment of the application provides a method for extending a three-dimensional waveguide to the surface of a substrate, preparing a waveguide with a high refractive index by deposition on the substrate, and placing SNSPDs in the waveguide or at the center where the light intensity is maximum, so that the high-speed detection rate of the SNSPDs close to GHz is realized by enhancing the light absorption efficiency of the SNSPDs.

According to some embodiments of the application, the three-dimensional waveguide and the optical device integrated in the first waveguide are combined together in the above manner, and efficient and high-speed detection of single photons can be realized through low-loss optical transmission between the three-dimensional waveguide and the first waveguide and high light intensity in or on the surface of the first waveguide. The thickness and width of the first waveguide can be optimally set according to the optical loss between the first waveguide and the three-dimensional waveguide and the absorption efficiency of the optical device, for example, the first waveguide is set to be an adiabatic taper structure, so that low-loss optical transmission between waveguides with different sizes can be realized, for example, through evanescent wave coupling.

Fig. 3 is a side view of an integrated three-dimensional waveguide optical assembly 200 in another embodiment.

Referring to the embodiment in fig. 3, the optical device 201 in fig. 3 is located at the center of the thickness of the first waveguide 202 where the light intensity is maximum, so that the light absorption efficiency of the optical device 201 can be enhanced, and thus the optical device with a shorter length can be used to achieve light absorption with nearly 100% efficiency, while ensuring high-speed detection at GHz.

Fig. 4 and 5 are side and top views of a further embodiment of an integrated three-dimensional waveguide optical assembly 300.

Referring to the optical assembly 300 in yet another embodiment in fig. 4 and 5, an optical device 302 is coupled to the other end of the first waveguide 301 opposite to the one end 303. The surface width of one end 303 of the first waveguide 301 along the transmission direction (direction b in fig. 5) of light in the first waveguide 301 may be gradually increased to a first width 301a, and then gradually decreased from the first width 301a to a second width 301b, so that the tapered structure of the first waveguide 301 may achieve low-loss light transmission between the three-dimensional waveguide 304 and the first waveguide 301 and maximization of the absorption efficiency of the optical device 302.

As shown in fig. 4 and 5, the structure in which the thickness of a portion of the first waveguide 301 is gradually changed in the direction b can further reduce optical loss.

Fig. 6 is a side view of an integrated three-dimensional waveguide optical package 400 in yet another embodiment.

Referring to the embodiment in fig. 6, the optical device 401 in fig. 6 is located at the center where the light intensity of the first waveguide 402 is the largest, so that the light absorption efficiency of the optical device 401 can be enhanced.

The present embodiment further provides an optical chip, which includes a plurality of optical components in the foregoing embodiments.

The present embodiment also provides a method for manufacturing an optical assembly integrated with a three-dimensional waveguide, where when an optical device is located between a first waveguide and a substrate, the method for manufacturing the optical assembly may include the following steps:

s10, depositing silicon oxynitride with the same refractive index as that of the substrate on the surface of the substrate to obtain a composite structure;

s20, directly writing a three-dimensional waveguide obliquely passing through a medium interface in the composite structure by using femtosecond laser;

s30, removing the deposited silicon oxynitride layer to obtain a three-dimensional waveguide extending to the surface of the substrate;

s40, depositing and preparing an optical device on the substrate, then depositing and preparing the first waveguide, polishing and grinding the surface of the first waveguide to prepare the optical component integrated with the three-dimensional waveguide.

In S40, the first waveguide may be deposited first, and then the optical device may be deposited.

The embodiment also provides another method for manufacturing an optical component integrated with a three-dimensional waveguide, and when the optical device is located at the position where the light intensity is maximum at the center of the first waveguide, the method for manufacturing another optical component may include the following steps:

s101, after the three-dimensional waveguide is prepared in the step S30, depositing a first waveguide material layer with proper thickness on a substrate;

s102, depositing and preparing an optical device on the first waveguide material layer;

s103, depositing a first waveguide material layer on the structure of the prepared optical device, polishing and grinding a first waveguide film layer on the optical device, and photoetching to prepare an optical waveguide to obtain the optical component of the integrated three-dimensional waveguide, wherein the optical device is positioned in the center of the first waveguide.

The femtosecond laser has the characteristics of extremely short pulse width, extremely high peak power and extremely wide coverage spectrum range, and the three-dimensional waveguide is prepared by the femtosecond processing technology, so that the three-dimensional waveguide has excellent characteristics which are not possessed by a plurality of traditional technologies in the precise processing process of the three-dimensional waveguide. The extremely short pulse width of the femtosecond laser can generate extremely high power instantly, so that redundant heat cannot be generated, the phenomena of cracking, damage and the like of the three-dimensional waveguide in the processing process are avoided, and the three-dimensional waveguide with high quality is obtained.

The three-dimensional waveguide prepared by femtosecond laser direct writing and other modes is combined with the optical device, so that the absorption efficiency of the optical device to an optical field can be improved. By the method, the SNSPD can be clamped between the first waveguide and the substrate or at the position where the optical intensity of the center of the first waveguide is maximum. Meanwhile, the waveguide with the proper refractive index can be selected, the proper waveguide size is designed, and the result that the light intensity near the optical device at the center of the first waveguide is strongest under the condition of the same optical power in the waveguide is optimally achieved. As an illustration of possible effects, without detailed optimization, absorption of over 99.8% could be achieved using U-shaped SNSPDs of 10 micron length, calculated by absorption simulation with typical niobium nitride (NbN), simply placing the SNSPD in the center of the first waveguide. And when the length of the nanowire is 10 micrometers, the detection rate above GHz can be realized.

While the above specification teaches exemplary embodiments of particular arrangements of the embodiments, these embodiments are not intended to be limiting, and the above application presents the best mode of practicing the invention. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above description. Therefore, the appended claims should be construed to cover all such changes and modifications as fall within the true spirit and scope of the application. Any and all equivalent ranges and contents within the scope of the claims should be considered to be within the intent and scope of this application.

Claims (10)

1. An optical assembly incorporating a three-dimensional waveguide, comprising:

a substrate;

a three-dimensional waveguide located inside the substrate;

a first waveguide positioned over the substrate, wherein an end of the three-dimensional waveguide extends to a surface of the substrate and is coupled with at least a portion of the first waveguide, an

An optical device coupled to the first waveguide,

wherein a surface of one end of the first waveguide is tapered such that light can enter the first waveguide from the three-dimensional waveguide by evanescent coupling.

2. An optical assembly according to claim 1, wherein the optical device is located within or on a surface of the first waveguide.

3. The optical assembly of claim 1, wherein the optical device is located over the surface of the substrate and at least a portion of the first waveguide encapsulates at least a portion of the optical device.

4. The optical assembly of claim 1, wherein the first waveguide is deposited grown over the substrate.

5. The optical assembly of claim 1, wherein the first waveguide comprises at least one of a silicon nitride waveguide and a silicon oxynitride waveguide.

6. The optical assembly of claim 1, wherein the one end of the three-dimensional waveguide is coupled to at least a portion of one end of the first waveguide.

7. The optical assembly of claim 6, wherein the optical device is coupled to another end of the first waveguide opposite the one end.

8. An optical assembly according to claim 6, wherein the surface width of the one end of the first waveguide increases to a first width along the direction of light transmission in the first waveguide.

9. An optical assembly according to claim 8, wherein the surface width of the one end of the first waveguide tapers to a second width after increasing to a first width along the direction of light transmission in the first waveguide.

10. An optical chip, characterized in that it comprises a plurality of optical components according to any one of the preceding claims 1-9.

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