On-chip integrated multifunctional photonic device and preparation method thereof

Abstract

The invention discloses an on-chip integrated multifunctional photonic device and a preparation method thereof, and relates to the field of multifunctional photonic devices and preparation thereof. The invention provides an on-chip integrated multifunctional photonic device. The on-chip integrated multifunctional photonic device is composed of a substrate with a rectangular etching groove array, and adjacent substrate materials and air grooves in the groove array are alternately arranged to form a periodic unit. When electromagnetic waves are emitted to the periodic structure of the etching groove array in different directions, due to the film interference effect, the photonic device has the functions of an antireflection film and a reflection increasing film in different incident directions, and the functions of high-transmission polarization conversion, total transmission and perfect reflection of waves can be achieved in different frequency bands. According to the photonic device, on-chip integration design is adopted, so that the device can be compatible with an existing photonic platform and can be embedded into an existing photonic chip, the integration degree, the micromation degree and the manufacturing efficiency of the device are improved, multiple functions can be integrated on the same platform, and the comprehensive performance of a system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of on-chip integrated photonic devices and preparation thereof, and in particular to an on-chip integrated multifunctional photonic device and a preparation method thereof. Background Art

[0002] With the rapid development of optical communication, optical computing and optical information processing technologies, on-chip photonic integration technology has gradually become an important way to meet the needs of high-efficiency optical information processing. At present, most on-chip integrated photonic devices are mainly single-function, such as frequency selection, phase control and polarization conversion. Although these single-function devices meet some application requirements, they are insufficient in high-integration and multifunctional systems. Even if some multifunctional devices try to integrate total transmission with total reflection, phase control and polarization conversion, their efficiency and performance are still greatly limited. For example, such devices often cannot make full use of on-chip space resources. At the same time, due to the complex optical structure, they are prone to large optical losses and poor performance consistency, which makes it difficult to meet the high integration, low complexity, multifunctionality and high performance required by current photonic integrated systems. In addition, most photonic devices have fixed optical characteristics in a single incident direction and frequency band, and cannot flexibly adapt to a variety of working scenarios, limiting the flexibility and efficiency of system design. At the same time, the design and preparation of multifunctional photonic devices still face challenges. The multifunctional characteristics require precise design of material microstructures, which usually requires multi-physical field collaborative optimization. At the same time, the preparation of micro-nano device structures puts forward high precision requirements for processing technology. In response to these challenges, the present invention proposes a multifunctional, highly integrated on-chip integrated multifunctional photonic device and its preparation method, which combines the theory of anti-reflection film and anti-reflection film in different incident directions of the same device, and can achieve multifunctional integration of full light transmission, perfect reflection and polarization conversion, and can achieve the coordinated work of the above multiple optical functions on the chip, and combines the optimized preparation process to ensure its processing accuracy and performance stability. The present invention can significantly improve the integration of photonic systems, effectively reduce the connection loss between devices and reduce overall energy consumption, laying the foundation for the development of next-generation photonic integrated circuits and optical information processing systems.

[0003] On-chip integration technology aims to integrate multiple optical functional modules on a substrate to form a compact, efficient, and low-power photonic system, which can significantly improve the system integration, reduce the volume and reduce the cost. The on-chip integrated structural design avoids the coupling loss caused by optical fiber connection, while enhancing the reliability and stability of the system. Compared with traditional electronic integration technology, on-chip photonic systems have lower power consumption and better performance in high-speed, large-capacity information transmission. However, most of the existing on-chip photonic devices realize specific functions (such as transmission or reflection) in a single band or a single direction, with single functions and obvious limitations. In response to these problems, the present invention introduces anti-reflection film and anti-reflection film technology into the structural design of on-chip photonic devices, innovatively realizes full transmission and perfect reflection of light in different incident directions, and combines micro-nano structure design to realize polarization conversion function. Although photonic technology is quite mature, the effective integration of high-performance multifunctional devices into existing photonic platforms still needs to overcome challenges such as material matching and structural design. The present invention proposes a multifunctional, highly integrated on-chip integrated multifunctional photonic device. By applying on-chip integration technology to integrated optical circuit boards, it can not only solve the high loss problem of traditional electronic integration in the infrared, near-infrared and terahertz bands, but also fine-tune the multifunctionality of the device by adjusting the multidimensional parameters of the device structure. Compared with the existing photonic devices that realize optical functions through a single dielectric film or metal film, the present invention can flexibly control the phase, amplitude and polarization of electromagnetic waves in a wider band range (such as infrared, near-infrared and terahertz bands), while reducing the complex coupling and optical losses in traditional multilayer structures. This highly integrated design not only significantly improves the utilization efficiency of on-chip space resources, but also ensures the stability and consistency of optical performance through optimized processing technology, providing a new solution for the multifunctionality and efficiency of modern photonic systems. At the same time, this integrated design can effectively reduce the volume, cost and complexity of traditional photonic systems, so that on-chip integrated multifunctional photonic devices can better adapt to the needs of modern information processing, sensing and communication systems. Summary of the invention

[0004] In order to solve the problems existing in the above-mentioned prior art, the present invention provides an on-chip integrated multifunctional photonic device and a preparation method thereof. Through innovative precise structural design, geometric structure optimization and loose preparation technology, the photonic device can achieve high-efficiency, low-loss and multifunctional regulation of infrared, near-infrared and terahertz waves on the same platform, making the application more flexible and extensive, and also compatible with existing photonic technology, suitable for large-scale integration.

[0005] To achieve the above-mentioned purpose, the present invention provides an on-chip integrated multifunctional photonic device and a preparation method thereof, comprising: the on-chip integrated multifunctional photonic device is composed of a rectangular substrate with a rectangular etched groove array, adjacent substrate materials and air grooves in the groove array are alternately arranged to form a periodic unit, and its period width parallel to the extension direction of the array is P, and in the periodic unit structure, the widths of the air grooves and the substrate materials are w1 and w2 (w1+w2=P), respectively, wherein the widths of w1 and w2 are both less than one twelfth of the wavelength of the working electromagnetic wave.

[0006] When the photonic device is incident with an electromagnetic wave along a direction perpendicular to the extension direction of the array, it has the functions of an anti-reflection film and an anti-reflection film, and due to the periodicity of the groove array structure and the diffraction and interference effects of the grating, it can realize a total reflection function and a polarization conversion function with high transmittance and high polarization conversion rate in different frequency bands, and under the same polarization function, there are multiple combinations of w1 and w2 in the unit structure of a fixed period P; when the photonic device is incident with an electromagnetic wave along a direction parallel to the extension direction of the array, it also has the functions of an anti-reflection film and an anti-reflection film, and through the thin film interference effect, it can respectively realize a wide-bandwidth perfect reflection function and a full transmission function in a specific frequency band.

[0007] The polarization state of the electromagnetic wave is [E x ,E y ] T When the wave enters the photonic device perpendicular to the array extension direction, the transmission polarization state of the wave changes to [T x ,T y ] T , and the relationship between the incident polarization state and the transmitted polarization state of the wave is as follows:

[0008] Wherein, the subscripts i and j represent the polarization directions of the incident electromagnetic wave and the transmitted electromagnetic wave, respectively. ii and t ij Corresponding to the transmission coefficients of co-polarized waves and vertically polarized waves respectively.

[0009] When the electromagnetic wave is incident on the photonic device in a direction perpendicular to the extending direction of the array, the transmittance T corresponding to the transmission polarization converter function of the photonic device k and polarization conversion efficiency P k They are:

[0010] Here, the subscript k represents the incident direction of the input wave.

[0011] When the electromagnetic wave enters the on-chip integrated multifunctional photonic device in a direction parallel to the array extension direction, due to the interference effect of the thin film, the reflected light at multiple interfaces in a specific frequency band constructively interferes to enhance the reflection, and the accumulated reflection of the multi-layer periodic groove array structure achieves an extremely high reflectivity, which is described as follows:

[0012] Among them, n H and n L are the refractive indices of the high refractive index substrate material and air respectively, N is the number of periods of the unit in the rectangular etched groove array, and the same applies when the incident light is perpendicular to the extension direction of the array.

[0013] When the electromagnetic wave enters the on-chip integrated multifunctional photonic device in a direction parallel to the array extension direction, due to the interference effect of the thin film, a full transmission effect can also be achieved in a specific frequency band, as described below:

[0014] Among them, n f is the effective refractive index of the periodic unit, and the same applies when the incidence is perpendicular to the extension direction of the array.

[0015] Optionally, the optical performance target can be fine-tuned by changing w1 and w2 and adjusting the shape and size parameters of the rectangular etched groove array, such as length l, width w and thickness h.

[0016] Optionally, the air slot width w1 and the substrate material width w2 in the periodic metamaterial unit structure satisfy:

[0017] Where c is the speed of light in vacuum, ω is the angular frequency of the incident light, f is the frequency of the incident light, and n is the refractive index of the semiconductor material. The polarization phase is tuned to the target, and

[0018] Optionally, the thickness d and the unit effective refractive index n of the layered array film structure formed by the alternating stacking of substrate materials and air slots can be precisely designed. f , can achieve the best interference enhancement to achieve a near-perfect high reflectivity. The unit period thickness d = λ / (4n f ), λ is the wavelength of the incident light.

[0019] Optionally, by increasing the number of periodic arrangement layers of the unit cells in the rectangular etched groove array or the thickness thereof in a direction parallel to the array extension direction, the reflection bandwidth of the multifunctional photonic device can be further improved.

[0020] Optionally, the periodically arranged array of etched grooves is preferably regular rectangular etched grooves, the purpose of which is to accurately control the wave propagation path in the grooves, reduce the diffraction loss caused by non-ideal geometry (such as elliptical or conical structures), and maximize the use of the waveguide effect in the grooves and the resonance characteristics of the surface plasma waves to improve the performance of the multifunctional photonic device.

[0021] Optionally, the rectangular groove array is formed by etching on the substrate material.

[0022] Furthermore, the substrate material is preferably an intrinsic semiconductor, such as gallium arsenide, silicon, germanium, indium phosphide, zinc oxide, etc.

[0023] The method for preparing the on-chip integrated multifunctional photonic device of the present invention takes intrinsic silicon as an example, and the specific steps are as follows:

[0024] Step 1: Apply a photoresist mask to define the etching pattern on a rectangular silicon wafer, and use ultraviolet (UV) exposure equipment to expose the photoresist according to the mask pattern (rectangular etching groove array). After exposure, immerse the silicon wafer in a developer to remove the unexposed part of the photoresist and leave the pattern of the exposed part.

[0025] Step 2, use reactive ion etching (RIE) technology to perform dry etching, and etch the silicon wafer by using a plasma of SF6 (sulfur hexafluoride) and O2 (oxygen) mixed gas, where SF6 is used to etch silicon, and O2 helps to remove organic matter and photoresist. The etching process only removes the silicon surface exposed by the photoresist pattern to form the required groove array.

[0026] Step 3: After etching is completed, the silicon wafer is rinsed with deionized water to remove any residual etching products or photoresist, thereby finally completing the preparation of an on-chip integrated multifunctional photonic device based on intrinsic silicon.

[0027] The innovative features of the on-chip integrated multifunctional photonic device of the present invention are mainly reflected in the following three points: (1) a rectangular groove array is formed on the substrate material by etching, which effectively reduces the connection loss of the device and reduces the overall energy consumption, thereby improving the efficiency and stability of the device. At the same time, the rectangular etched groove array enhances the electromagnetic response of the device in a wider band (such as infrared, near-infrared and terahertz bands); (2) combined with micro-nano structure design, the size and arrangement of the etched grooves in the unit are precisely adjusted, and the phase and polarization of the wave are regulated by using the grating diffraction and interference effects and the thin film interference effect generated periodically by the groove array structure, achieving the effects of anti-reflection film and anti-reflection film in different directions, and realizing perfect wave reflection, ultra-high transmission, phase regulation and polarization conversion functions in different frequency bands. High integration; (3) compatible with modern photonic technology, realizing on-chip integration of photonic devices, reducing size and cost, and improving device compatibility, promoting the integration and miniaturization of multifunctional photonic devices, and forming a compact, efficient and low-power photonic system.

[0028] Compared with the prior art, the present invention has achieved the following technical effects:

[0029] The present invention proposes an on-chip integrated multifunctional photonic device and its preparation method through the innovative rectangular etched groove structure design and the introduction of anti-reflection film and anti-reflection film technology. The device integrates multiple optical function modules on a substrate to form a compact, efficient, and low-power photonic system. Compared with traditional devices, the present invention combines anti-reflection film and anti-reflection film technology in the on-chip structure, innovatively realizes the full transmission, perfect reflection and polarization conversion functions of light, and realizes the coordinated operation of multiple optical functions on the chip. For example, in different terahertz bands, the transmittance of the present invention can reach more than 0.85, the reflectivity can reach more than 0.98, and the polarization conversion efficiency exceeds 90%. Compared with the prior art, the present invention has significantly improved the band width, transmission efficiency and functional integration. This multifunctional and highly integrated design reduces the device volume and connection loss, reduces the overall energy consumption, and lays a technical foundation for the development of the next generation of photonic integrated circuits and optical information processing systems.

[0030] The core advantage of the present invention lies in the innovative application of on-chip integrated technology. By accurately designing the parameters such as the groove width, groove period and groove depth of the micro-nano etched grooves in the on-chip structure, combined with the synergistic effect of the anti-reflection film and the anti-reflection film, the device can efficiently achieve full transmission, perfect reflection and polarization conversion functions in different incident directions. The existing single dielectric film technology is usually only effective within a specific wavelength range (such as ±10nm), and although the metal film can achieve enhanced reflection, the absorption loss can be as high as 20%-30%, which is difficult to meet the high efficiency requirements. At the same time, most of these technologies are limited to fixed functions of a single band or a single incident angle. The present invention combines the effects of the anti-reflection film and the anti-reflection film, and expands the functional band range through microstructure design. It is particularly suitable for wide-band applications in the infrared, near-infrared and terahertz bands. In the wide band range of terahertz, it achieves high-efficiency functions with a transmittance greater than 0.85 and a reflectivity greater than 0.98, while significantly reducing the loss of traditional metal films to less than 5%. At the same time, it takes into account the functional adaptability of multi-directional incidence, meeting the current needs of on-chip integrated multifunctional photonic devices.

[0031] In terms of preparation process, the present invention makes full use of mature photolithography and etching technology to achieve high-precision processing of complex micro-nano structures. Compared with the existing multilayer film design, the processing flow of the present invention is more simplified, avoiding the coupling loss caused by optical fiber connection in traditional photonic devices, and significantly enhancing the stability and reliability of the system. In addition, no special materials or equipment are required in the preparation process, which is compatible with existing semiconductor photonic manufacturing processes, greatly reducing production costs and complexity, and laying a solid foundation for large-scale industrial applications.

[0032] The highly integrated design of the present invention effectively reduces the volume and complexity of traditional photonic systems and improves the consistency and stability of optical performance. This highly integrated design significantly improves the utilization efficiency of on-chip space resources, provides a new solution for the multifunctionality and efficiency of modern photonic systems, and can better meet the needs of modern information processing, sensing and communication systems, especially in the next generation of photonic computing and high-speed communication fields. It has broad application prospects. DETAILED DESCRIPTION

[0033] In order to make the purpose, features, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail in the following examples. It should be understood that the specific implementation cases described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] The on-chip integrated multifunctional photonic device is composed of a rectangular substrate with a rectangular etched groove array. Adjacent substrate materials and air grooves in the groove array are alternately arranged to form a periodic unit, and the period width parallel to the extension direction of the array is P. In the periodic unit structure, the widths of the air grooves and the substrate material are w1 and w2 (w1+w2=P), respectively; the widths of w1 and w2 in the periodic unit structure are both less than one twelfth of the wavelength of the working electromagnetic wave.

[0035] When the photonic device is incident with an electromagnetic wave along a direction perpendicular to the extension direction of the array, it has the functions of an anti-reflection film and an anti-transmission film, and due to the periodicity of the slot array structure and the diffraction and interference effects of the grating, the propagation directions and phases of waves of different diffraction orders change, and when the diffracted waves propagate in multiple slots, the waves on different paths are superimposed on each other to form a phase difference, which causes the waves to interfere with each other, forming differentiated intensity distributions and phase distributions, thereby being able to achieve linear polarization to circular polarization, linear polarization to linear polarization, circular polarization to linear polarization, and circular polarization to circular polarization conversion functions with high transmittance and high polarization conversion rate in a specific frequency band; when the unit period P is fixed, the same polarization function is achieved, and there are multiple combinations of w1 and w2 in the structure; at the same time, total reflection function can be achieved based on the anti-reflection film theory in different frequency bands.

[0036] When the photonic device is incident with an electromagnetic wave parallel to the extension direction of the array, it also has the functions of an anti-reflection film and an anti-reflection film. Since the high-refractive index substrate material and air are alternately stacked to form a periodically arranged rectangular etched groove array, and through the thin film interference effect, the reflected light at multiple interfaces in a specific frequency band constructively interferes to enhance the reflection, and through the cumulative reflection of the multi-layer periodic groove array structure, an extremely high reflectivity is achieved, and finally the perfect reflector function is realized. At the same time, according to the anti-reflection film theory, a full transmission function can also be achieved in a specific frequency band.

[0037] The substrate material of the present invention is preferably an intrinsic semiconductor, such as gallium arsenide, silicon, germanium, indium phosphide, zinc oxide, etc.

[0038] The preparation method of the on-chip integrated multifunctional photonic device of the present invention is as follows: taking intrinsic silicon as an example, a mask with a photoresist defining an etching pattern is coated on a rectangular substrate material, and an ultraviolet (UV) exposure device is used to expose the photoresist according to the mask pattern (rectangular etching groove array). After exposure, the silicon wafer is immersed in a developer to remove the unexposed part of the photoresist and leave the pattern of the exposed part; reactive ion etching (RIE) technology is used to perform dry etching, and the silicon wafer is etched by using a plasma of a mixed gas of SF6 (sulfur hexafluoride) and O2 (oxygen), wherein SF6 is used to etch silicon, and O2 is helpful to remove organic matter and photoresist, and the etching process only removes the silicon surface exposed by the photoresist pattern to form the required groove array; after etching is completed, the silicon wafer is rinsed with deionized water to remove any residual etching products or photoresist, and finally the preparation of the on-chip integrated multifunctional photonic device based on intrinsic silicon is completed.

[0039] When the working electromagnetic wave is incident along a direction perpendicular to the extension direction of the array, the photonic device has the functions of an anti-reflection film and an anti-reflection film, and due to the periodicity of the slot array structure and the diffraction and interference effects of the grating, the propagation direction and phase of waves of different diffraction orders change, and when the diffracted waves propagate in multiple slots, the waves on different paths overlap to form a phase difference, causing the waves to interfere with each other, forming differentiated intensity distributions and phase distributions, thereby being able to achieve linear polarization to circular polarization, linear polarization to linear polarization, circular polarization to linear polarization, and circular polarization to circular polarization conversion functions under high transmittance and high polarization conversion rate in a specific frequency band, and under the same polarization function, when the unit period P is fixed Under the same polarization function, there are multiple combinations of w1 and w2 in the structure. At the same time, the total reflection function can be realized based on the anti-reflection film theory in different frequency bands; when the working electromagnetic wave is incident along the direction parallel to the extension of the array, it also has the function of anti-reflection film and anti-reflection film. Due to the alternating stacking of high-refractive index substrate materials and air to form a periodically arranged rectangular etched groove array, and through the thin film interference effect, the reflective light at multiple interfaces in a specific frequency band is constructively interfered to enhance the reflection, and through the cumulative reflection of the multi-layer periodic groove array structure, an extremely high reflectivity is achieved, and finally the perfect reflector function is realized. At the same time, according to the anti-reflection film theory, the full transmission function can also be realized in a specific frequency band. At the same time, due to the rectangular shape of the etched groove, it can accurately control the propagation path of the wave in the groove, reduce the diffraction loss caused by non-ideal geometry (such as elliptical or conical structures), and can maximize the use of the waveguide effect in the groove and the resonance characteristics of the surface plasma wave, so as to improve the performance of the multifunctional photonic device.

[0040] The present invention is further described in detail below in conjunction with a number of specific implementation cases, and the specific parameters of each embodiment are as follows:

[0041] Example 1

[0042] The anti-reflection and anti-reflection functions of the etched groove array based on the intrinsic gallium arsenide (GaAs) substrate in the terahertz band and the polarization conversion function under high polarization conversion efficiency were verified. Periodic rectangular etching was performed on the rectangular substrate (intrinsic GaAs) to obtain an etched groove array unit with a length l of 28μm, a width w1 of 2.4μm, and a thickness h of 14μm, wherein the width w2 of the substrate material adjacent to the air groove is 1.6μm, the total width of the etched groove array is 72μm, and the unit period width P is 4μm, that is, the number of layered unit periods in the groove array is 18 layers, and the widths of w1 and w2 are both less than one twelfth of the wavelength of the working electromagnetic wave.

[0043] A linearly polarized electromagnetic wave is incident on the multifunctional photonic device along a direction perpendicular to the extension direction of the array. The photonic device has polarization conversion functions from linear polarization to left-handed circular polarization, linear polarization to linear polarization, and linear polarization to right-handed circular polarization at 2.8THz, 5.6THz, and 7.5THz with a high transmittance of 0.96 and a high polarization conversion rate of 90%. At the same time, the transmission coefficients of the co-polarized wave and the vertically polarized wave at 5.6THz are 0 and 1 respectively, and the ellipticity is 1. At the frequency points of 2.8THz and 7.5THz, the transmission coefficients of the co-polarized wave and the vertically polarized wave are equal, but their ellipticities are 1 and -1 respectively. Except for the specific frequency points, the transmittance of the photonic device in the frequency band of 2-8THz is above 0.85, which highlights the anti-reflection function of the high transmittance and the polarization conversion function of the high polarization conversion rate of the photonic device. At the same time, in the frequency bands of 1.6THz~2.2THz and 8.4THz~9.1THz, the reflectivity of the photonic device is 0.82 or above, highlighting the reflection enhancement function of the photonic device.

[0044] Example 2

[0045] The anti-reflection function and perfect reflection function of the rectangular etched groove array based on the intrinsic silicon (Si) substrate in the terahertz band were verified. Periodic rectangular etching was performed on the rectangular substrate (intrinsic Si) to obtain an etched groove array unit with a length l of 14μm, a width w1 of 0.83μm, and a thickness h of 6μm, wherein the width w2 of the substrate material adjacent to the etched air groove is 0.57μm, the total width of the etched groove array is 36.4μm, and the unit period width P is 1.4μm, that is, the number of layered unit periods in the groove array is 26 layers, and the widths of w1 and w2 are both less than one twelfth of the wavelength of the working electromagnetic wave.

[0046] When a linearly polarized electromagnetic wave is incident on the multifunctional photonic device in a direction parallel to the extension direction of the array, the photonic device forms a perfect reflector function with a bandwidth of 12 THz in the 9-21 THz band, with a reflectivity of 0.98 or above, and forms a full transmission function with a bandwidth of 8 THz in the 22-28 THz band, with a transmittance of 0.92 or above. At the same time, the more periodic units in the rectangular etched groove array or the wider the width of the rectangular etched groove in the direction parallel to the extension direction of the array, the wider the working bandwidth of the perfect reflection function of the on-chip integrated multifunctional photonic device.

[0047] Example 3

[0048] The anti-reflection and anti-reflection functions of the etched groove array based on the intrinsic zinc oxide (ZnO) substrate in the terahertz band and the polarization conversion function under high polarization conversion efficiency were verified. Periodic rectangular etching was performed on the rectangular substrate (intrinsic ZnO) to obtain an etched groove array unit with a length l of 23μm, a width w1 of 1.86μm, and a thickness h of 16μm, wherein the width w2 of the substrate material adjacent to the air groove is 1.24μm, the total width of the etched groove array is 46.5μm, and the unit period width P is 3.1μm, that is, the number of layered unit periods in the groove array is 15 layers, and the widths of w1 and w2 are both less than one twelfth of the working wavelength.

[0049] When a linearly polarized electromagnetic wave is incident on the multifunctional photonic device in a direction perpendicular to the extension direction of the array, the photonic device realizes a linear polarization to circular polarization with a high transmittance of 0.98 and a high polarization conversion rate of 96% at a frequency of 5.2THz. The transmission coefficients of the co-polarized wave and the vertically polarized wave are equal and the ellipticity is 1. At the same time, when the incident polarization angle is in the range of 30° to 55° and the wave frequency is in the range of 3.4THz to 6.2THz, the color transmittance of the photonic device is 0.89 or above, which highlights its anti-reflection function and polarization conversion function. At the same time, in the frequency bands of 1.7THz to 2.3THz and 7.5THz-7.9THz, the reflectivity of the photonic device is 0.84 or above, which highlights the anti-reflection function of the photonic device.

[0050] Compared with existing individual photonic devices, the on-chip integrated multifunctional photonic device of the present invention has smaller thickness, smaller volume, and significantly enhanced integrability; it has the advantages of high optical property control efficiency and wide control range.

[0051] Finally, it should be noted that the above implementation is only used to illustrate the technical solution of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An on-chip integrated multifunctional photonic device and a method for preparing the same, relating to the field of multifunctional photonic devices and their preparation, characterized in that: The on-chip integrated multifunctional photonic device is composed of a rectangular substrate with a rectangular etched groove array, in which adjacent substrate materials and air grooves are alternately arranged to form a periodic unit, and the periodic width parallel to the array extension direction is P. In the periodic unit structure, the widths of the air grooves and the substrate material are w1 and w2 (w1+w2=P), respectively; the widths of w1 and w2 in the periodic unit structure are both less than one twelfth of the wavelength of the working electromagnetic wave; when the photonic device is incident with an electromagnetic wave perpendicular to the array extension direction, it has The functions of the anti-reflection film and the anti-reflection film, and due to the periodicity of the groove array structure and the diffraction and interference effects of the grating, the total reflection function and the polarization conversion function with high transmittance and high polarization conversion rate can be realized in different frequency bands. At the same time, when the unit period P is fixed, the same polarization function is realized, and there are multiple combinations of w1 and w2 in the structure; when the photonic device is incident with an electromagnetic wave parallel to the extension direction of the array, it also has the functions of the anti-reflection film and the anti-reflection film, and through the thin film interference effect, a wide-bandwidth perfect reflection function and a full transmission function can be realized in a specific frequency band.

2. The on-chip integrated multifunctional photonic device according to claim 1, characterized in that: The substrate material includes but is not limited to N-type doped semiconductors, P-type doped semiconductors and intrinsic semiconductors, preferably intrinsic semiconductors.

3. The intrinsic semiconductor according to claim 2, characterized in that: The selected intrinsic semiconductor needs to have stable, low-loss optical properties and be easy to integrate with the photonic platform. Preferred intrinsic semiconductors are silicon, germanium, gallium arsenide, indium phosphide and zinc oxide.

4. The on-chip integrated multifunctional photonic device according to claim 1, characterized in that: The number of units in the periodically arranged rectangular etching groove array is 6 or more.

5. The on-chip integrated multifunctional photonic device according to claim 1, characterized in that: The polarization state of the working electromagnetic wave is linear polarization, circular polarization or elliptical polarization, and its waveband covers near infrared, infrared light and terahertz waves, and preferably the waveband is terahertz electromagnetic waves.

6. The intrinsic semiconductor according to claim 3, taking intrinsic semiconductor silicon as substrate material as an example, is characterized in that: A mask with a photoresist defining an etching pattern is applied on a rectangular substrate material (intrinsic silicon wafer), and the photoresist is exposed through the mask pattern (rectangular etching groove array) using an ultraviolet (UV) exposure device. The exposure time is controlled at 10-20 seconds. After exposure, the silicon wafer is immersed in a special developer (e.g., 0.26N TMAH solution) and developed for 2 minutes to remove the unexposed portion of the photoresist, leaving the pattern of the exposed portion, and finally forming an initial pattern of rectangular etching grooves.

7. The intrinsic semiconductor silicon substrate according to claim 6, characterized in that: Reactive ion etching (RIE) technology is used for dry etching. The silicon substrate is etched by using a plasma of a mixed gas of SF6 (sulfur hexafluoride) and O2 (oxygen). SF6 is used to etch silicon, while O2 helps to remove organic matter and photoresist. The etching process only removes the silicon surface exposed by the photoresist pattern to form the required rectangular groove array.

8. The dry etching according to claim 7, characterized in that: After etching is completed, the silicon wafer is rinsed with deionized water to remove any residual etching products or photoresist, and finally the preparation of an on-chip integrated multifunctional photonic device using intrinsic silicon as the substrate material is completed.

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