Sensitivity-sensing integrated optical sensor and preparation method thereof

Abstract

The invention discloses a sensing integrated optical sensor and a preparation method thereof, and relates to the technical field of on-chip optical sensing. The device comprises a silicon substrate, an oxidation buried layer is deposited on the top of the silicon substrate, a first rectangular waveguide is installed above the oxidation buried layer, one end of the first rectangular waveguide is flush with the oxidation buried layer, a second rectangular waveguide is installed at the other end of the first rectangular waveguide, and a reverse tapering part is arranged at the end, facing the center of the oxidation buried layer, of the first rectangular waveguide. A forward tapering part is arranged at the end, away from the center of the oxidation buried layer, of the second rectangular waveguide. The hybrid integration of the metal plasma resonant cavity is realized based on on-chip optical interconnection, the quasi-continuous spectrum bound state is excited by strong coupling between resonance modes, the quality factor is greatly improved while high-sensitivity on-chip optical sensing is realized, the optical transmission loss is relatively low, and the application range is wide. The method has a practical application effect on the construction of a novel on-chip optical sensing system.

Description

Technical Field

[0001] The present invention relates to the field of on-chip optical sensing technology, and in particular to an optical sensor with integrated senses and a preparation method thereof. Background Art

[0002] With the development of integrated photonic technology, people hope to improve the working characteristics of devices by improving optoelectronic integration technology and reduce the corresponding process difficulty and production cost. As one of the core devices of optoelectronic integration, the development of on-chip optical sensors has gradually tended to be miniaturized, with high quality factor, low insertion loss, high sensitivity and other characteristics. On the other hand, the on-chip photonic interconnection that is being established and improved urgently needs stable and multi-functional integrated optoelectronic devices. Taking all these factors into consideration, the photonic resonant structure is one of the best solutions at present.

[0003] Recent studies have shown that plasma resonant structures can introduce some new functions to integrated optical circuits, which helps to improve the integration of chips. At present, several designs based on on-chip optical interconnection have been proposed, such as phase coupling structure and near-field coupling structure, which can be used to realize on-chip plasma resonant devices. In order to avoid the high transmission loss of plasma waveguides and reduce the difference in processing technology with traditional photonic links, integrated plasma resonant devices can use dielectric waveguides to provide optical excitation and interconnection to improve working performance and meet the requirements of large-scale hybrid integration. Therefore, SOI-based integrated photonic-plasma hybrid links are reliable platforms for on-chip plasma resonant devices, but there are two major difficulties in realizing the combination of plasma and quasi-continuum bound states in on-chip optical interconnection: first, there is a lack of reliable plasma structures that can excite low-loss, high-quality factor quasi-continuum bound state optical signals; second, most of the current quasi-continuum bound state photonic structures are independent devices and work based on off-chip light excitation, which is difficult to meet the needs of on-chip optical interconnection. To this end, we propose a plasma resonant quasi-continuum bound state on-chip optical sensor and preparation method. Summary of the invention

[0004] The purpose of the present invention is to provide an optical sensor with integrated synaesthesia and a preparation method. Based on the strong coupling theory of optical modes, a metal plasma resonant cavity with a supercavity configuration is developed, and the high compatibility of the SOI platform is fully utilized. In combination with silicon waveguides, an on-chip photon-plasma hybrid optical path is constructed to achieve on-chip optical interconnection integration of subwavelength plasma resonant cavities, thereby solving the problems of high loss, low integration, and small quality factor of plasma sensors.

[0005] To achieve the above object, the present invention provides the following technical solution: an optical sensor with integrated sense, comprising a silicon substrate, a buried oxide layer is deposited on the top of the silicon substrate, a first rectangular waveguide is installed above the buried oxide layer, one end of the first rectangular waveguide is kept flush with the buried oxide layer, and a second rectangular waveguide is installed on the other end, a reverse taper portion is provided at one end of the first rectangular waveguide facing the center of the buried oxide layer, a forward taper portion is provided at one end of the second rectangular waveguide away from the center of the buried oxide layer, and the forward taper portion is completely covered in the reverse taper portion to form a directional coupling structure;

[0006] The first rectangular waveguide and the second rectangular waveguide as a whole form a coupling unit, the number of the coupling units is at least two, and the two coupling units are symmetrically arranged along the length direction of the buried oxide layer with the center line of the buried oxide layer as the symmetry axis;

[0007] A gold resonant ring is installed at the center between the two coupling units, a plasma resonant cavity is formed inside the gold resonant ring, and two openings are provided in the gold resonant ring near the second rectangular waveguide along the straight waveguide direction for near-field coupling between the second rectangular waveguides on both sides and the plasma resonant cavity;

[0008] A gold nanorod is arranged inside the gold resonance ring. The gold nanorod is in the shape of a long strip, and the center point of the gold nanorod coincides with the center of the gold resonance ring. The gold nanorod is perpendicular to the connection direction of the two coupling units, so as to achieve indirect coupling between the gold nanorod and the gold resonance ring.

[0009] Furthermore, the first rectangular waveguide is made of SU-8 photoresist, and the refractive index of SU-8 photoresist in the near-infrared band is 1.53.

[0010] Furthermore, the second rectangular waveguide is made of silicon material, and the thickness of the second rectangular waveguide is set to 220 nm.

[0011] Furthermore, the reverse tapered portion is integrally formed with the first rectangular waveguide, and the width of the reverse tapered portion gradually decreases along one side of the oxide buried layer toward the center;

[0012] The forward tapered portion is integrally formed with the second rectangular waveguide, and the forward tapered portion gradually decreases along the center of the buried oxide layer toward one side.

[0013] Furthermore, the thickness of the buried oxide layer is set to 2 μm.

[0014] Furthermore, the width of the gold nanorod is 100 to 150 nm, the length is 0.8 to 1 μm, and there is a certain distance between the two ends of the gold nanorod and the gold resonant ring.

[0015] Furthermore, the inner radius of the gold resonance ring is 1.3 to 1.5 μm, the outer radius is 1.6 to 1.8 μm, and the width of the opening is set to 100 to 150 nm.

[0016] Furthermore, the center of the gold resonant ring coincides with the center point of the line connecting the centers of the second rectangular waveguides arranged on both sides, and there is a certain distance between the second rectangular waveguides on both sides and the openings on the gold resonant ring.

[0017] Furthermore, the second rectangular waveguide and the plasma resonant cavity form an on-chip optical interconnection through near-field coupling, and the light field input into the second rectangular waveguide contacts and couples with the metal resonant cavity, thereby exciting a plasma mode, wherein the plasma mode includes a "bright" mode and a "dark" mode.

[0018] According to a second aspect of the present invention, the present invention provides a method for preparing a synaesthesia integrated optical sensor, which is used to prepare the above-mentioned synaesthesia integrated optical sensor, and specifically includes the following steps:

[0019] S1. First, a 400 nm thick electron beam photoresist layer is laid on the top silicon of the silicon substrate, and a second rectangular waveguide is produced by electron beam lithography and plasma etching;

[0020] S2. Laying a 3μm thick layer of SU-8 photoresist on the silicon substrate, a first rectangular waveguide was prepared by one-time dumping, photolithography, development, and curing;

[0021] S3. Laying a 500 nm thick electron beam photoresist layer on the buried oxide layer (2) of the silicon substrate (1), and simultaneously producing the pattern of the gold resonant ring (7) and the gold nanorods (9) by electron beam lithography overlay process;

[0022] S4. A 220 nm thick gold layer is deposited on the chip with the electron beam photoresist pattern by a metal deposition process. After the metal deposition is completed, the chip is placed in an acetone solution and the electron beam photoresist on the chip is removed by ultrasonic cleaning. At this time, only the gold resonant ring (7) and the gold nanorods (9) directly deposited on the oxide buried layer (2) are retained, and the metal resonant cavity is prepared;

[0023] S5. The patterned chip is cleaned for a second time to remove all residual photoresist and complete the device preparation;

[0024] S6. Finally, for the optical sensor with integrated senses that has been prepared, packaging based on the light array system is performed, the single-mode optical fiber and the first rectangular waveguide (3) are end-face coupled and connected, and then bonded with ultraviolet curing glue to complete the optical packaging of the device.

[0025] The present invention has at least the following beneficial effects:

[0026] The optical sensor with integrated senses of the present invention realizes hybrid integration of metal plasma resonant cavities based on on-chip optical interconnection, utilizes strong coupling between resonant modes to excite quasi-continuous spectrum bound states, realizes high-sensitivity on-chip optical sensing, greatly improves the quality factor, and has low optical transmission loss, which has practical application effects for constructing a new on-chip optical sensing system.

[0027] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a three-dimensional schematic diagram of the overall structure of the present invention;

[0029] Figure 2 It is a top view schematic diagram of the overall structure of the present invention;

[0030] Figure 3 Schematic diagram of an on-chip spot converter composed of a first rectangular waveguide and a second rectangular waveguide in the present invention, wherein (a) is a structural diagram of the on-chip spot converter; (b) is a coupling efficiency diagram of the spot converter and the silicon waveguide; and (c) is a coupling efficiency diagram of the spot converter and the single-mode optical fiber.

[0031] Figure 4 It is a schematic diagram of a simple harmonic oscillator oscillation model of the plasma resonant cavity in the present invention under the excitation of an incident light field;

[0032] Figure 5 It is a working schematic diagram of the on-chip optical sensor in the present invention connected to an optical fiber system.

[0033] Figure 6 Figure 1 is a demonstration diagram of on-chip light sensing by an integrated optical sensor of the present invention, wherein (a) is a schematic diagram of the chip directly contacting the liquid to be tested during the test process; (b) is a schematic diagram of the simulated (red dotted line) and actual (black solid circle) spectral shifts of the quasi-continuous spectrum bound state resonance peak in the test spectrum at different ethanol / deionized water concentrations; (c) is a schematic diagram of the normalized transmission spectrum of the on-chip light sensor under the conditions of 0%, 5%, 10% and 15% ethanol / deionized water mixtures.

[0034] Reference numerals:

[0035] 1. Silicon substrate; 2. Oxide buried layer; 3. First rectangular waveguide; 4. Reverse tapered portion; 5. Second rectangular waveguide; 6. Forward tapered portion; 7. Gold resonant ring; 8. Opening; 9. Gold nanorods. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0037] The invention comprises a first rectangular waveguide, a second rectangular waveguide, a gold resonant ring with symmetrical openings and a gold nanorod. The whole device is located on an oxide buried layer of a silicon substrate. The number of the first rectangular waveguide and the second rectangular waveguide are both set to two. The two first rectangular waveguides are respectively used as input and output ports for end-face coupling with an external single-mode optical fiber. The two second rectangular waveguides are also mainly divided into an input part and an output part. The second rectangular waveguide of the input part mainly introduces a TE polarized optical signal into a resonant cavity and excites a plasma resonant mode through near-field coupling. The second rectangular waveguide of the output part mainly derives a quasi-continuous spectrum bound state mode formed by coupling in the resonant cavity. The metal plasma resonant cavity is used as a core unit, and its structure satisfies the excitation of two plasma modes, namely, "bright" and "dark". Under the near-field coupling and excitation of the second rectangular waveguide, the "bright" and "dark" modes in the metal plasma resonant cavity are strongly coupled, thereby exciting a quasi-continuous spectrum bound state.

[0038] See also Figure 1-Figure 5 The present invention provides a technical solution: an optical sensor with integrated sense, comprising a silicon substrate 1, a buried oxide layer 2 is deposited on the top of the silicon substrate 1, a first rectangular waveguide 3 is installed above the buried oxide layer 2, one end of the first rectangular waveguide 3 is kept flush with the buried oxide layer 2, and a second rectangular waveguide 5 is installed on the other end, a reverse taper portion 4 is arranged at one end of the first rectangular waveguide 3 facing the center of the buried oxide layer 2, and a forward taper portion 6 is arranged at one end of the second rectangular waveguide 5 away from the center of the buried oxide layer 2, and the forward taper portion 6 is completely covered in the reverse taper portion 4 to form a directional coupling structure;

[0039] The first rectangular waveguide 3 and the second rectangular waveguide 5 constitute a coupling unit as a whole. The number of the coupling units is at least two, and the two coupling units are symmetrically arranged along the length direction of the buried oxide layer 2 with the center line of the buried oxide layer 2 as the symmetry axis;

[0040] A gold resonant ring 7 is installed at the center between the two coupling units, a plasma resonant cavity is formed inside the gold resonant ring 7, and two openings 8 are provided in the gold resonant ring 7 near the second rectangular waveguide 5 along the straight waveguide direction, for near-field coupling between the second rectangular waveguides 5 on both sides and the plasma resonant cavity;

[0041] A gold nanorod 9 is arranged inside the gold resonance ring 7. The gold nanorod 9 is in the shape of a long strip, and the center point of the gold nanorod 9 coincides with the center of the gold resonance ring 7. The gold nanorod 9 is perpendicular to the connection direction of the two coupling units, so as to achieve indirect coupling between the gold nanorod 9 and the gold resonance ring 7.

[0042] According to the technical solution of this embodiment, the first rectangular waveguide 3 serves as a secondary waveguide structure, one end of which is end-face coupled with an external single-mode optical fiber to introduce light in the communication band of the optical fiber system or output the on-chip quasi-continuous spectrum bound state optical signal, and the other end is coupled with the second rectangular waveguide 5 to achieve template conversion and provide efficient optical signal coupling. The first rectangular waveguide 3 is made of SU-8 photoresist, and SU-8 is an epoxy resin polymer GM-1040 produced by Gerste ltec. The refractive index of SU-8 photoresist in the near-infrared band is 1.53.

[0043] Furthermore, the second rectangular waveguide 5 is a primary optical interconnection structure, which is mainly used for the transmission of on-chip optical signals. It can be near-field coupled with the plasma resonant cavity as an excitation source for exciting the plasma mode, and can also detect the quasi-continuous spectrum bound state optical signal in the resonant cavity. The second rectangular waveguide 5 is made of silicon material, and the thickness of the second rectangular waveguide 5 is set to 220nm.

[0044] According to the technical solution of this embodiment, the reverse tapered portion 4 is integrally formed with the first rectangular waveguide 3, and the width of the reverse tapered portion 4 gradually decreases along one side of the oxide buried layer 2 toward the center. The forward tapered portion 6 is integrally formed with the second rectangular waveguide 5, and the width of the forward tapered portion 6 gradually decreases along the center of the oxide buried layer 2 toward one side. The forward tapered portion 6 is completely enclosed in the reverse tapered portion 4 to form a directional coupling structure, so that the pattern spot size can be converted between the first rectangular waveguide 3 and the second rectangular waveguide 5.

[0045] According to the technical solution of this embodiment, the thickness of the buried oxide layer 2 deposited on the SOI silicon substrate 1 is set to 2μm, serving as the SiO2 lower cladding layer of the entire on-chip optical interconnection structure. It should be noted that the thickness of the buried oxide layer 2 is not specifically limited in this embodiment and can be selected according to actual needs.

[0046] According to the technical solution of this embodiment, the outer ring of the metal plasma resonant cavity is called a gold resonant ring 7 with symmetrical openings 8, and the resonant structure at the center of the resonant cavity is called a gold nanorod 9. The gold resonant ring 7 completely wraps the gold nanorod 9, and only two symmetrical openings 8 are opened near the second rectangular waveguide 5. The size range of the opening 8 can be set to 100 to 150nm, and can be specifically set to 150nm. The gold resonant ring 7 is directly coupled with the second rectangular waveguide 5 to form an on-chip optical interconnection. Since the focusing distance is very close, the light field input into the silicon waveguide can directly contact and couple with the metal plasma resonant cavity without a long distance of spatial divergence, thereby exciting the plasma "bright" mode; and the gold nanorod 9, as a regulating unit of the plasma mode, is coupled with the gold resonant ring 7. Indirect coupling can generate a plasma "dark" mode and can satisfy the coupling of the "bright" and "dark" modes. The two modes hybridize with each other in a narrow cavity, further forming a plasma quasi-continuous spectrum bound state, and the plasma quasi-continuous spectrum bound state is coupled with the second rectangular waveguide 5 of the output part in the form of an evanescent field, thereby being exported in the form of an optical signal. By reasonably designing the metal plasma resonant cavity with "bright" and "dark" structures, not only can the strong coupling of plasma modes be achieved and the quasi-continuous spectrum bound state be excited, but the cavity structure is compact and the size is smaller than that of an ordinary dielectric supercavity. After hybrid integration with the second rectangular waveguide 5, an on-chip photon-plasma hybrid optical path based on SOI is formed, making the application of on-chip optical sensor devices in optical fiber systems possible.

[0047] It should be noted that the plasma "bright" mode is a specific wave mode in plasma, also known as, in this mode, the interaction between electrons and positive ions leads to resonant fluctuations; this mode usually appears in plasma systems, such as gas discharge, plasma layer, plasma nuclear fusion, etc. The plasma "bright" mode is of great significance for the study of plasma physics, energy transfer and plasma device design;

[0048] The plasma "dark" mode is a wave mode in the plasma. In contrast to the plasma bright mode, in the plasma dark mode, the changes in the electromagnetic field or electron density are small and not easy to observe. This mode usually requires more sensitive experimental techniques or numerical simulation methods to detect. The study of plasma dark mode helps to gain a deeper understanding of the behavior and properties of plasma, and is of great significance to the field of plasma physics.

[0049] Further, the width of the gold nanorod 9 is 100 to 150 nm, the length is 0.8 to 1 μm, and there is a certain distance between the two ends of the gold nanorod 9 and the gold resonant ring 7, and the distance can be set to 200 nm. This embodiment is not specifically limited here and can be selected according to actual needs;

[0050] The center of the gold resonant ring 7 coincides with the center point of the center line of the second rectangular waveguides 5 arranged on both sides. There is a certain distance between the second rectangular waveguides 5 on both sides and the openings 8 on the gold resonant ring 7, and the distance is set to 200nm.

[0051] like Figure 4 As shown, according to the Lorentz coupled oscillator model, the resonant cavity designed in this embodiment can be divided into two "bright" structures and one "dark" structure, and the mode coupling satisfies the following rules:

[0052]

[0053] In the above formula, x j , γ j and ω j (j=b1, b2, d) represents the resonance amplitude, damping rate and resonance frequency of the “bright” (b1 and b2) and “dark” (d) modes; κ ij (i, j = b1, b2, d) represents the coupling coefficient between the oscillating structures i and j; light excitation E(t) = E0e -iωt , resonance amplitude x j (t) = x j e -iωt For this symmetrical “bright” oscillator, γ b1 =γ b2 =γ b ,ω b1 =ω b2 =ω b , κ b1b2 =κ b2b1 =κ bb , κ b1d =κ b2d =κ db1 =κ db2 =κ bd ; In addition, the resonant amplitudes of the two “bright” oscillators are the same, i.e. x b1 =x b2 =x b ; Considering x b and x d All are harmonics, and the amplitude of the "bright" oscillator can be given by:

[0054]

[0055] Among them, the equivalent capacitance of the "bright" or "dark" oscillating structure In Gamma d and γ b Much smaller than ω b or d In the case of Cb and C d can be regarded as a constant; the mutual coupling between the two "bright" structures helps to form the resonant frequency from ω b Offset to ω bb The hybrid plasma mode satisfies ω bb =(ω b 2 ±κ bb ) 1 / 2 .

[0056] Specifically, in order to improve the integration of the device, the structure of the on-chip optical interconnection in this embodiment mainly uses a silicon rectangular plate (the second rectangular waveguide 5) as the core layer. However, due to the relatively large refractive index of silicon, it is difficult to directly couple the end face with the external single-mode optical fiber. Figure 3 As shown, in this embodiment, the first rectangular waveguide 3 is used as a secondary waveguide to form an on-chip pattern spot converter with the second rectangular waveguide 5. Figure 3 As shown in (a) in the figure, the coupling efficiency between the optical fiber and the device is greatly improved. The TE mode conversion efficiency based on the structure is as high as more than 80%, which is beneficial to reducing the insertion loss of the device. In order to achieve the purpose of exciting the quasi-continuous spectrum bound state of the plasma, the gold nanorod 9 is placed at the center of the gold resonant ring 7 with a symmetrical opening 8 to form a resonant cavity with a compact structure and a "bright" and "dark" mode structure. The plasma modes thus excited are mainly of "bright" and "dark" types, and are both bound in a very small cavity area, thereby providing conditions for the hybridization between the "bright" and "dark" modes and promoting the generation of quasi-continuous spectrum bound states. Because the second rectangular waveguide 5 is symmetrically distributed on both sides of the metal resonant cavity, and the distance between the two is only 200nm, and it is facing the opening 8 of the gold resonant ring 7, the plasma "bright" mode can be excited in the resonant cavity through the TE polarization mode in the second rectangular waveguide 5. At the same time, the plasma quasi-continuous spectrum bound state formed in the resonant cavity can also be coupled with the silicon rectangular waveguide at the output end through near-field coupling, and finally exported by the waveguide in the form of an optical signal.

[0057] In this embodiment, the second rectangular waveguide 5 is used to form an on-chip optical interconnection by near-field coupling, which is directly coupled to the metal plasma resonant cavity on the chip, so it is easier to realize chip-based optical packaging, such as Figure 5 As shown, since no upper cladding is made, the metal plasma resonance structure is directly exposed to the air and can be in direct contact with the surrounding environment. Therefore, it can not only meet the interconnection with the optical fiber system, but also perform real-time sensing of the surrounding environment. Once the refractive index of the environment changes, the resonant characteristics of the plasma mode will also change, and the frequency of the quasi-continuous spectrum bound state after hybridization will shift. By detecting the amount of frequency shift, the refractive index of the surrounding environment can be further determined, and then the specific composition of the environment can be understood.

[0058] like Figure 6 As shown in (a), the quasi-continuous spectrum bound state on-chip optical sensor based on the plasma resonance structure of this embodiment can achieve high-sensitivity refractive index detection for mixtures of ethanol and deionized water of different concentrations (0% to 15%). Figure 6 As shown in (c), with the increase of ethanol / deionized water concentration, it can be seen that the quasi-continuum bound state resonance peak undergoes an obvious red shift. Figure 6 The linear fitting results in (b) show that the refractive index sensitivity of the device can reach about 1090nm / RI U; all these data points can be accurately fitted by a straight line, showing good refractive index sensing linear response characteristics. At the same time, the detection limit of the device can be defined as DL=3σ / S, where σ is the standard deviation of the detection signal baseline. For the on-chip optical sensor of this embodiment, σ is close to 0.1nm, and DL can reach about 0.0003RI U, which is the highest level among devices of the same type.

[0059] In summary, the optical sensor with integrated sense of the present invention realizes hybrid integration of metal plasma resonant cavity based on on-chip optical interconnection, utilizes strong coupling between resonant modes to excite quasi-continuous spectrum bound states, realizes high-sensitivity on-chip optical sensing, greatly improves the quality factor, and has low optical transmission loss. It has practical application effects for constructing a new on-chip optical sensing system.

[0060] Embodiment 2:

[0061] This embodiment provides a method for preparing a synaesthesia integrated optical sensor, which is used to prepare the above-mentioned synaesthesia integrated optical sensor, and specifically includes the following steps:

[0062] S1. First, a 400 nm thick electron beam photoresist layer is laid on the top silicon of the silicon substrate 1, and a second rectangular waveguide 5 is produced by electron beam lithography and plasma etching;

[0063] S2. Laying a 3μm thick layer of SU-8 photoresist on the silicon substrate 1, a first rectangular waveguide 3 is prepared by one-time dumping, photolithography, development, and curing;

[0064] S3. A 500nm thick electron beam photoresist layer is laid on the buried oxide layer 2 of the silicon substrate 1, and a pattern of the gold resonant ring 7 and the gold nanorods 9 is simultaneously produced by an electron beam lithography overlay process;

[0065] S4. A 220 nm thick gold layer is deposited on the chip with the electron beam photoresist pattern by a metal deposition process. After the metal deposition is completed, the chip is placed in an acetone solution and the electron beam photoresist on the chip is removed by ultrasonic cleaning. At this time, only the gold resonant ring 7 and the gold nanorods 9 directly deposited on the buried oxide layer 2 are retained, and the metal resonant cavity is prepared;

[0066] S5. The patterned chip is cleaned for a second time to remove all residual photoresist and complete the device preparation;

[0067] S6. Finally, for the completed integrated optical sensor, packaging based on the light array system is carried out, the single-mode optical fiber is end-face coupled and docked with the first rectangular waveguide 3, and UV-curing adhesive is used for bonding to complete the optical packaging of the device. The entire manufacturing process is compatible with the current CMOS processing technology.

[0068] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0069] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. When an element is referred to as being "assembled on", "installed on", "fixed on" or "set on" another element, it can be directly on the other element or there can also be a centered element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a centered element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and are not intended to be the only implementation method.

[0070] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0071] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

Claims

1. An optical sensor with integrated sense, comprising a silicon substrate (1), characterized in that: A buried oxide layer (2) is deposited on the top of the silicon substrate (1); a first rectangular waveguide (3) is installed above the buried oxide layer (2); one end of the first rectangular waveguide (3) is kept flush with the buried oxide layer (2); a second rectangular waveguide (5) is installed on the other end; a reverse tapered portion (4) is provided at one end of the first rectangular waveguide (3) facing the center of the buried oxide layer (2); a forward tapered portion (6) is provided at one end of the second rectangular waveguide (5) away from the center of the buried oxide layer (2); the forward tapered portion (6) is completely covered in the reverse tapered portion (4) to form a directional coupling structure; The first rectangular waveguide (3) and the second rectangular waveguide (5) integrally form a coupling unit, the number of the coupling units is at least two, and the two coupling units are symmetrically arranged along the length direction of the buried oxide layer (2) with the center line of the buried oxide layer (2) as the symmetry axis; A gold resonant ring (7) is installed at the center between the two coupling units, a plasma resonant cavity is formed inside the gold resonant ring (7), and two openings (8) are provided in the gold resonant ring (7) near the second rectangular waveguide (5) along the straight waveguide direction, for near-field coupling between the second rectangular waveguides (5) on both sides and the plasma resonant cavity; A gold nanorod (9) is arranged inside the gold resonance ring (7); the gold nanorod (9) is in the shape of a long strip, and the center point of the gold nanorod (9) coincides with the center of the circle of the gold resonance ring (7); the gold nanorod (9) is perpendicular to the connection direction of the two coupling units, so as to achieve indirect coupling between the gold nanorod (9) and the gold resonance ring (7).

2. The optical sensor with integrated synaesthesia according to claim 1, characterized in that: The first rectangular waveguide (3) is made of SU-8 photoresist, and the refractive index of SU-8 photoresist in the near-infrared band is 1.

53.

3. The optical sensor with integrated synaesthesia according to claim 2, characterized in that: The second rectangular waveguide (5) is made of silicon material, and the thickness of the second rectangular waveguide (5) is set to 220 nm.

4. The optical sensor with integrated synaesthesia according to claim 3, characterized in that: The reverse tapered portion (4) is integrally formed with the first rectangular waveguide (3), and the width of the reverse tapered portion (4) gradually decreases along one side of the oxide buried layer (2) toward the center; The forward tapered portion (6) is integrally formed with the second rectangular waveguide (5), and the forward tapered portion (6) gradually decreases along the center of the oxide buried layer (2) toward one side.

5. The optical sensor with integrated synaesthesia according to claim 3, characterized in that: The thickness of the buried oxide layer (2) is set to 2 μm.

6. The optical sensor with integrated synaesthesia according to claim 5, characterized in that: The gold nanorod (9) has a width of 100 to 150 nm and a length of 0.8 to 1 μm, and there is a certain distance between the two ends of the gold nanorod (9) and the gold resonant ring (7).

7. The optical sensor with integrated synaesthesia according to claim 6, characterized in that: The inner radius of the gold resonance ring (7) is 1.3 to 1.5 μm, the outer radius is 1.6 to 1.8 μm, and the width of the opening (8) is set to 100 to 150 nm.

8. The optical sensor with integrated synaesthesia according to claim 7, characterized in that: The center of the gold resonant ring (7) coincides with the center point of the center line of the second rectangular waveguides (5) arranged on both sides, and there is a certain distance between the second rectangular waveguides (5) on both sides and the upper openings (8) of the gold resonant ring (7).

9. The optical sensor with integrated synaesthesia according to claim 8, characterized in that: The second rectangular waveguide (5) and the plasma resonant cavity form an on-chip optical interconnection by means of near-field coupling, and the light field input into the second rectangular waveguide (5) contacts and couples with the metal resonant cavity, thereby exciting a plasma mode, wherein the plasma mode includes a "bright" mode and a "dark" mode.

10. A method for preparing an optical sensor with integrated synaesthesia, used for preparing an optical sensor with integrated synaesthesia according to any one of claims 1 to 9, characterized in that: The details include: S1. First, a 400 nm thick electron beam photoresist layer is laid on the top silicon of the silicon substrate (1), and a second rectangular waveguide (5) is produced by electron beam lithography and plasma etching; S2. Laying a 3 μm thick layer of SU-8 photoresist on the silicon substrate (1), a first rectangular waveguide (3) is prepared by one-time casting, photolithography, development and curing; S3. Laying a 500 nm thick electron beam photoresist layer on the buried oxide layer (2) of the silicon substrate (1), and simultaneously producing the pattern of the gold resonant ring (7) and the gold nanorods (9) by electron beam lithography overlay process; S4. A 220 nm thick gold layer is deposited on the chip with the electron beam photoresist pattern by a metal deposition process. After the metal deposition is completed, the chip is placed in an acetone solution and the electron beam photoresist on the chip is removed by ultrasonic cleaning. At this time, only the gold resonant ring (7) and the gold nanorods (9) directly deposited on the oxide buried layer (2) are retained, and the metal resonant cavity is prepared; S5. The patterned chip is cleaned for a second time to remove all residual photoresist and complete the device preparation; S6. Finally, for the optical sensor with integrated senses that has been prepared, packaging based on the light array system is performed, the single-mode optical fiber and the first rectangular waveguide (3) are end-face coupled and connected, and then bonded with ultraviolet curing glue to complete the optical packaging of the device.

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