Photon terahertz communication transmitting device and method for installing photoelectric detector

Abstract

The invention relates to a photon terahertz communication transmitting device and a method for installing a photoelectric detector. The photon terahertz communication transmitting device comprises a substrate, a dielectric layer located on the substrate, a device layer located on the dielectric layer and a photoelectric detector. The device layer comprises a first end face coupler used for coupling carrier light emitted by a first optical fiber; the second end face coupler is used for coupling local oscillation light emitted by the second optical fiber; the modulation unit is used for modulating the carrier light to obtain signal light; the multimode interferometer is used for carrying out coupling and frequency mixing on the local oscillation light and the signal light to obtain frequency mixing light; the photoelectric detector is arranged on the grating and is used for converting the frequency mixing light into a terahertz signal and transmitting the terahertz signal to the microstrip line. The terahertz communication transmitting device provided by the invention is simple in structure, reasonable in layout, high in integration level and capable of effectively reducing power consumption.

Description

Technical Field

[0001] The present application relates to the field of optical quantum communication technology, and in particular to a photon terahertz communication transmitting device and a method for installing a photoelectric detector. Background Art

[0002] Microwave photonic transceivers take advantage of the inherent advantages of photonic technology and have the advantages of wide operating bandwidth, low loss, flexibility and anti-electromagnetic interference. Although microwave photonic systems have made significant breakthroughs, most transceivers use separate components or low-integration chips, and still face the problems of complex structure, high power consumption, large size and high cost. Summary of the invention

[0003] Based on this, it is necessary to provide a photon terahertz communication transmitting device and a method for installing a photodetector to address the problems of complex structure and high cost of microwave photon transceiver chips in the prior art.

[0004] In a first aspect, the present application provides a photon terahertz communication transmitting device, the photon terahertz communication transmitting device comprising a substrate, a dielectric layer located on the substrate, a device layer located on the dielectric layer, and a photodetector; the device layer comprises:

[0005] A first end face coupler, used for coupling the carrier light emitted by the first optical fiber;

[0006] A second end face coupler, used for coupling the local oscillator light emitted by the second optical fiber;

[0007] A modulation unit, used for modulating the carrier light to obtain a signal light;

[0008] A multi-mode interferometer, used for coupling the local oscillator light and the signal light to obtain mixed frequency light;

[0009] The photodetector is configured on the device layer, and is used to convert the mixed frequency light into a terahertz signal, and transmit the terahertz signal to a microstrip line;

[0010] The carrier light, the local oscillator light, the signal light, and the mixed frequency light are respectively transmitted through transmission waveguides, the device layer is provided with a plurality of grooves, and each of the transmission waveguides is respectively arranged in each of the grooves.

[0011] In one embodiment, the modulation unit includes a modulator, which is a coherent modulator composed of an I-channel modulator and a Q-channel modulator, the I-channel modulator includes a first optical waveguide and a first RF electrode, the Q-channel modulator includes a second optical waveguide and a second RF electrode, the difference between a propagation refractive index of the first RF electrode and a propagation refractive index of the first optical waveguide is within a preset range, and / or the difference between a propagation refractive index of the second RF electrode and a propagation refractive index of the second optical waveguide is within a preset range.

[0012] In one embodiment, the modulation unit further includes:

[0013] A first beam splitter, used for splitting the carrier light into a first sub-carrier light and a second sub-carrier light;

[0014] A second beam splitter, used for splitting the first branched carrier light into two paths and inputting the two paths into the I-path modulator, and modulating the I-path modulator to obtain an I-path modulated signal;

[0015] A third beam splitter, used for splitting the second sub-carrier light into two paths and inputting the two paths into the Q-path modulator, and modulating the two paths by the Q-path modulator to obtain a Q-path modulated signal;

[0016] A beam combiner is used to combine the I-channel modulated signal with the Q-channel modulated signal to obtain the signal light.

[0017] In one embodiment, a thermal image shifter is provided at the signal input end of the optical waveguide in the I-channel modulator; and / or,

[0018] The signal input end and the signal output end of the optical waveguide in the Q-path modulator are both provided with thermal image shifters.

[0019] In one of the embodiments, in the I-channel modulator and / or the Q-channel modulator, the RF electrode is located on a side of the optical waveguide, and the RF electrode is a periodic T-shaped traveling wave electrode.

[0020] In one embodiment, the dielectric layer has a first receiving waveguide at the first end face coupler, the first receiving waveguide matches the first optical fiber mode field, and the first end face coupler includes a first tapered fully etched waveguide and a first tapered half-etched waveguide, so that the light emitted by the first optical fiber is coupled by the first receiving waveguide, the first tapered fully etched waveguide, and the first tapered half-etched waveguide in sequence;

[0021] and / or,

[0022] The dielectric layer has a second receiving waveguide at the second end face coupler, and the second receiving waveguide matches the second optical fiber mode field. The second end face coupler includes a second tapered fully etched waveguide and a second tapered half-etched waveguide, so that the light emitted by the second optical fiber is coupled in sequence by the second receiving waveguide, the second tapered fully etched waveguide and the second tapered half-etched waveguide.

[0023] In one embodiment, the substrate is made of silicon, the dielectric layer is made of silicon oxide, the device layer is a lithium niobate film, and the transmission waveguide is made of lithium niobate.

[0024] In one embodiment, the photodetector is connected to the microstrip line via an air bridge, so as to transmit the terahertz signal to the microstrip line via the air bridge.

[0025] Second invention, the present application provides a method for installing a photoelectric detector, comprising the following steps:

[0026] A photodetector is provided; a target mounting structure is provided, the target mounting structure comprises a substrate, a dielectric layer located on the substrate, and a device layer located on the dielectric layer, the device layer having a target mounting position and a microstrip line of the photodetector; the device layer comprises: a first end face coupler for coupling a carrier light emitted by a first optical fiber; a second end face coupler for coupling a local oscillator light emitted by a second optical fiber; a modulation unit for modulating the carrier light to obtain a signal light; a multimode interferometer for coupling the local oscillator light and the signal light to obtain a mixed-frequency light; the photodetector is arranged on the device layer, and is used to convert the mixed-frequency light into a terahertz signal, and transmit the terahertz signal to the microstrip line; the carrier light, the signal light, and the mixed-frequency light are respectively transmitted through a transmission waveguide, the device layer is provided with a plurality of grooves, and each of the transmission waveguides is respectively arranged in each of the grooves;

[0027] forming a plurality of first positioning marks around the target installation position;

[0028] picking up the photodetector by a transfer stamp having a plurality of second positioning marks thereon;

[0029] Aligning each of the first positioning marks with each of the second positioning marks so that the transfer stamp is located at the target installation position;

[0030] The transfer stamp is removed to form an air bridge, and the photodetector and the microstrip line are connected via the air bridge.

[0031] In one embodiment, aligning each of the first positioning marks and each of the second positioning marks comprises:

[0032] Acquire a first image of the photon terahertz communication transmitting device and a second image of the transfer stamp, wherein the first image includes at least the plurality of first positioning marks, and the second image includes at least the plurality of second positioning marks, and acquire spatial position information of the first positioning marks and the second positioning marks based on an image recognition algorithm;

[0033] Based on a projection transformation algorithm, determining a projection position of the second positioning mark on the device layer, and determining a relative positional relationship between the projection position and the first positioning mark;

[0034] The position of the transfer stamp is adjusted based on the relative position relationship so that the projection position coincides with the first positioning mark, so as to achieve alignment of the first positioning mark and the second positioning mark.

[0035] In the above-mentioned photon terahertz communication transmitting device, there is a dielectric layer on the substrate, and there is a device layer on the dielectric layer. The device layer includes a first end face coupler, a second end face coupler, a modulation unit and a multimode interferometer, and the photodetector is located on the device layer. The first end face coupler is used to couple the carrier light, and the second end face coupler is used to couple the local oscillator light; after the carrier light enters the modulation unit for modulation, it carries a signal to obtain the signal light, and the signal light and the local oscillator light enter the multimode interferometer together for coupling and mixing, and the mixed light is output, and then the photodetector converts the mixed light into a terahertz signal and transmits it to the microstrip line, which is emitted by the microstrip line. The terahertz communication transmitting device provided by the present application has a simple structure, a reasonable layout, a high degree of integration, and effectively reduces power consumption.

[0036] In the above-mentioned method for installing a photodetector, the photodetector is installed at a target installation position on a target installation structure, and the target installation structure includes a substrate, a dielectric layer located on the substrate, and a device layer located on the dielectric layer; the device layer includes a target installation position and a microstrip line. First, a plurality of first positioning marks are formed around the target installation position, and then the photodetector is picked up by a transfer stamp with a second positioning mark. After aligning the first positioning mark and the second positioning mark, it indicates that the photodetector is transferred to the target installation position, and the transfer stamp can be removed. The method for installing a photodetector provided in the present application provides a heterogeneous integration solution. In the case where the materials of the photodetector and the device layer are different, heterogeneous integration can be achieved by using the installation method provided in the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 It is a schematic diagram of the structure of a photon terahertz communication transmitting device provided in one embodiment;

[0039] Figure 2 is a structural block diagram of a photon terahertz communication transmitting device provided in an embodiment;

[0040] Figure 3 It is a schematic diagram of the structure of the radio frequency electrode of the modulator in one embodiment;

[0041] Figure 4 is a schematic diagram of the structure at the position of the first end face coupler in one embodiment;

[0042] Figure 5 FIG. 4 is a flow chart of a method for installing a photodetector in one embodiment. DETAILED DESCRIPTION

[0043] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0045] See also Figure 1 and Figure 2 , Figure 1 A schematic structural diagram of a photonic terahertz communication transmitting device is shown. Figure 2 The structural block diagram of a photon terahertz communication transmitting device is shown. The present invention provides a photon terahertz communication transmitting device, which includes a substrate, a dielectric layer located on the substrate, a device layer located on the dielectric layer, and a photodetector. The device layer includes a first end face coupler, a second end face coupler, a modulation unit, and a multimode interferometer. The first end face coupler is used to couple carrier light, and the second end face coupler is used to couple local oscillator light. After the carrier light enters the modulation unit for modulation, it carries a signal to obtain signal light. The signal light and the local oscillator light enter the multimode interferometer together for coupling and mixing, and output mixed light. The mixed light is converted into a terahertz signal by the photodetector and transmitted to the microstrip line, and then emitted by the microstrip line.

[0046] Exemplarily, a grating may be provided on the device layer, and the grating is used to receive the mixed-frequency light emitted by the multi-mode interferometer. The photodetector may be configured on the grating to detect the mixed-frequency light transmitted on the grating.

[0047] Among them, transmission waveguides are formed between the first end face coupler and the modulation unit, between the modulation unit and the multimode interferometer, between the second end face coupler and the multimode interferometer, and between the multimode interferometer and the grating, so that the carrier light, the local oscillator light, the signal light, and the mixed light are transmitted through the transmission waveguides respectively. The device layer is provided with a plurality of grooves, and each transmission waveguide is respectively configured in each groove.

[0048] Specifically, the first end face coupler is used to couple the carrier light emitted by the first optical fiber; the second end face coupler is used to couple the local oscillator light emitted by the second optical fiber. The first end face coupler can couple the carrier light emitted by the first optical fiber, and couple the carrier light into the photon terahertz communication transmitting device, and the second end face coupler can couple the local oscillator light emitted by the second optical fiber, and couple the local oscillator light into the photon terahertz communication transmitting device. In this way, the end face coupler plays the role of coupling the light in the optical fiber to the photon terahertz communication transmitting device, and the optical fiber end face and the coupler are effectively docked, such as the first end face coupler and the first optical fiber end face are docked, the carrier light output by the first optical fiber is emitted into the first end face coupler, and the second end face coupler and the second optical fiber end face are docked, and the local oscillator light emitted by the second optical fiber is emitted into the second end face coupler.

[0049] Exemplarily, the carrier light is a light wave used to carry information, and the local oscillator light is a light wave with a fixed frequency. By mixing the carrier light and the local oscillator light, a new frequency can be output based on the mixing effect to reach the terahertz frequency band.

[0050] After the first end face coupler couples the carrier light, it is transmitted to the modulation unit through the transmission waveguide. The modulation unit is used to modulate the carrier light to obtain the signal light. Exemplarily, the modulation unit embeds information (such as audio, video or data) into the carrier light by changing the amplitude, frequency, phase and other characteristics of the carrier light, so that the information can be transmitted through the optical signal.

[0051] The modulation unit modulates the carrier light to obtain signal light with information. The signal light is transmitted to the multimode interferometer through a transmission waveguide, and the local oscillator light is directly transmitted to the multimode interferometer through another transmission waveguide. The multimode interferometer (MMI) is used to couple and mix the local oscillator light and the signal light to obtain mixed light. The signal light with data information and the local oscillator light are combined through a multimode interferometer to obtain mixed light. The photodetector can detect the mixed light and output a terahertz signal.

[0052] When a grating is provided, the mixed light output by the multimode interferometer can be transmitted to the grating through a transmission waveguide. Through the periodic structure of the grating, light waves of specific frequencies are selectively generated.

[0053] The photodetector can detect the mixed light in the grating, and is used to convert the mixed light into a terahertz signal, and is also used to transmit the terahertz signal to the microstrip line. The photodetector can realize photoelectric conversion and convert the optical signal into an electrical signal.

[0054] When there is a grating, a photodetector can be arranged on the grating. When there is a light signal on the grating, the photodetector can pick up the light signal in the grating and convert it into an electrical signal for output.

[0055] In the above-mentioned photon terahertz communication transmitting device, a dielectric layer is provided on the substrate, a device layer is provided on the dielectric layer, the device layer includes a first end face coupler, a second end face coupler, a modulation unit and a multimode interferometer, and a photodetector is located on the device layer. The first end face coupler is used to couple the carrier light, and the second end face coupler is used to couple the local oscillator light. After the carrier light enters the modulation unit for modulation, it carries a signal to obtain the signal light. The signal light and the local oscillator light enter the multimode interferometer together for coupling and mixing, and the mixed light is output. After that, the photodetector converts the mixed light into a terahertz signal and transmits it to the microstrip line, which is emitted by the microstrip line. The terahertz communication transmitting device provided in the present application has a simple structure, a reasonable layout, a high degree of integration, and effectively reduces power consumption.

[0056] In some embodiments, the substrate is made of silicon, the dielectric layer is made of silicon oxide, the device layer is made of lithium niobate film, and the transmission waveguide is made of lithium niobate. In traditional technology, photonic terahertz communication front-end chips are mainly concentrated in silicon photonic systems. Due to the limitations of the properties of the material itself, its application in high-frequency terahertz communication has been significantly restricted. Specifically, the electro-optical effect of silicon material is weak, which causes its transceiver performance to be affected in high-frequency applications, which is manifested as a lower carrier frequency and a smaller signal bandwidth. In addition, the silicon photonic system also has certain limitations in terms of modulation efficiency, transmission loss, etc.

[0057] The solution proposed in this embodiment is to provide a silicon oxide dielectric layer on the silicon substrate, and to provide lithium niobate (LiNbO 3 ) thin film as the device layer, and the modulation unit is prepared on the thin film lithium niobate material, which can effectively overcome the shortcomings of the traditional silicon photonic system. As a material with excellent electro-optical effect, lithium niobate material has far superior performance in electro-optical modulation, optical waveguide and nonlinear optics than silicon material. Especially in the terahertz frequency band, the electro-optical effect of lithium niobate can provide stronger modulation depth and higher frequency response, thereby significantly improving the bandwidth and transmission rate of the communication system.

[0058] In this way, this embodiment simultaneously utilizes the integration advantages and cost advantages of silicon materials and the high electro-optical effect advantages of lithium niobate materials, and sets the lithium niobate material on the silicon substrate through a silicon oxide dielectric layer, thereby reducing the loss caused by material mismatch and greatly improving the bandwidth and performance of the photonic terahertz communication system.

[0059] like Figure 1 As shown, in some embodiments, the modulation unit includes a modulator, and the modulator is a coherent modulator composed of an I-channel modulator and a Q-channel modulator. The I-channel modulator and the Q-channel modulator both include an optical waveguide and a radio frequency electrode, and the difference between the propagation refractive index of the radio frequency electrode and the propagation refractive index of the optical waveguide is within a preset range. The optical waveguide is a section of the transmission waveguide. For the convenience of description, the transmission waveguide at the position of the modulator is defined as the optical waveguide. It can be understood that the optical waveguide is a section of the transmission waveguide in the modulator, and the carrier light can be transmitted on the transmission waveguide, which is also included in the transmission in the modulator.

[0060] The I-path modulator includes a first optical waveguide and a first radio frequency electrode, the Q-path modulator includes a second optical waveguide and a second radio frequency electrode, the difference between the propagation refractive index of the first radio frequency electrode and the propagation refractive index of the first optical waveguide is within a preset range, and / or the difference between the propagation refractive index of the second radio frequency electrode and the propagation refractive index of the second optical waveguide is within a preset range. Figure 3 As shown, Figure 3 Schematic diagrams of modulator radio frequency electrodes in some embodiments are shown. Specifically, the first optical waveguide and the second optical waveguide are both transmission waveguides.

[0061] The first end face coupler couples to obtain carrier light, and the carrier light enters the optical waveguide of the I-channel modulator and the Q-channel modulator through the transmission waveguide. During the transmission of the optical waveguide, the carrier light applies an electric field through the RF electrode located on the side of the optical waveguide to modulate the light. The electric field applied by the RF electrode causes a change in the refractive index in the optical waveguide, changes the phase, amplitude and other parameters of the carrier light, and obtains a signal light carrying a signal after modulation. Exemplarily, the I-channel modulator controls the in-phase part of the signal, which is used to represent the amplitude part of the signal. The Q-channel modulator controls the orthogonal part of the signal, which is used to represent the phase information of the signal.

[0062] Wherein, the difference between the propagation refractive index of the RF electrode and the propagation refractive index of the optical waveguide is within a preset range, the RF propagation loss is small, and the electro-optical modulation efficiency is large. For example, the mode refractive index of the optical waveguide can be obtained by simulation using FDTD (Finite-Difference Time-Domain) software, and the mode refractive index of the RF electrode can be obtained by simulation using Comsol software.

[0063] Specifically, the modulator optical waveguide is simulated by FDTD software, the optical waveguide is designed to support only TE (Transverse Electric) mode transmission, and the mode refractive index of the optical waveguide is simulated. In some embodiments, in the I-channel modulator and / or the Q-channel modulator, the RF electrode is located on the side of the optical waveguide, and the RF electrode is a periodic T-shaped track wave electrode.

[0064] When simulating the RF electrode using Comsol software, by changing the RF electrode parameters d, W T , H T , W L and H L The parameters are such that the RF propagation refractive index is equal to the refractive index of the optical waveguide. Where d is the farthest distance between the RF electrodes on both sides, W T H is the width of the T-rail longitudinal rail in the first direction. T is the length of the T-rail longitudinal rail in the second direction, W L H is the width of the T-rail cross rail in the first direction. L It is the length of the T-rail cross rail in the second direction.

[0065] Continue to see Figure 1 In some embodiments, the modulation unit further includes a first beam splitter, a second beam splitter, a third beam splitter and a beam combiner. The first beam splitter is used to split the carrier light into a first sub-carrier light and a second sub-carrier light; the first sub-carrier light and the second sub-carrier light are respectively transmitted to an I-channel modulator and a Q-channel modulator for modulation. The second beam splitter is used to split the first sub-carrier light into two channels and then input the channels into the I-channel modulator, and obtain an I-channel modulated signal after being modulated by the I-channel modulator; the third beam splitter is used to split the second sub-carrier light into two channels and then input the channels into the Q-channel modulator, and obtain a Q-channel modulated signal after being modulated by the Q-channel modulator; the beam combiner is used to combine the I-channel modulated signal with the Q-channel modulated signal to obtain a signal light.

[0066] In simple terms, the carrier light is divided into two parts by the first beam splitter: the first branch carrier light and the second branch carrier light. The first branch carrier light passes through the second beam splitter and is divided into two paths and input to the I-path modulator. After modulation, an I-path modulated signal is obtained. The second branch carrier light passes through the third beam splitter and is divided into two paths and input to the Q-path modulator. After modulation, a Q-path modulated signal is obtained. The combiner combines the modulated signals of the I-path and Q-path to obtain the final signal light carrying the signal, which contains the information of IQ modulation.

[0067] In this embodiment, an IQ modulator is used to simultaneously transmit two different information streams, namely, an I-channel (in-phase) and a Q-channel (orthogonal) on the same carrier frequency, so that more data information can be transmitted within the same bandwidth, thereby greatly improving bandwidth utilization. Figure 1As shown, the IQ modulator in this embodiment is formed on the lithium niobate device layer, and can utilize the excellent electro-optical effect of lithium niobate. This is because the electro-optical coefficient of lithium niobate is very high, so that the lithium niobate modulator can support very high modulation frequency, so that it can work in an extremely high frequency range.

[0068] In some embodiments, a thermal image shifter is provided at the signal input end of the optical waveguide in the I-channel modulator. In some embodiments, a thermal image shifter is provided at both the signal input end and the signal output end of the optical waveguide in the Q-channel modulator. Thermal image shifter in the I-channel modulator: The thermal image shifter is located at the signal input end and is used to accurately adjust the phase or amplitude of the input optical signal. In the Q-channel modulator, the thermal image shifter is provided at the signal input end and the output end, which not only adjusts the transmission characteristics of the input signal, but also adjusts the output characteristics of the modulated optical signal. By controlling the thermal image shifter at the output end, the phase and amplitude of the signal can be fine-tuned, thereby optimizing the quality of the modulated signal.

[0069] Specifically, since temperature changes in the IQ modulator will affect the refractive index and electro-optical effect of the optical waveguide, a thermal imaging instrument is set at the signal input end of the I-channel modulator and the Q-channel modulator. The temperature of the optical waveguide is controlled within a preset temperature range through the thermal imaging instrument to reduce temperature drift and optimize the modulation performance.

[0070] The Q-channel modulator is used to modulate the phase of the carrier light, which is more sensitive to temperature changes. Temperature changes can cause changes in the refractive index of the optical waveguide. By setting a thermal imaging instrument at the signal output end of the Q-channel modulator and adjusting the temperature so that the optical waveguide is within the preset temperature range, the signal output by the I-channel modulator and the signal output by the Q-channel modulator are more stable when combined. Figure 4 , Figure 4 FIG. 1 shows a schematic diagram of the structure of the first end face coupler at the position of some embodiments. In some embodiments, the first end face coupler couples the light in the first optical fiber in three sections. The first section is in the dielectric layer SiO 2 Design waveguide on SiO 2 The waveguide and optical fiber are matched to the mode field to reduce optical loss. The second section is a fully etched tapered thin film lithium niobate waveguide to achieve SiO 2 The third section is a shallowly etched tapered thin-film lithium niobate waveguide, which realizes efficient optical coupling from the fully etched thin-film lithium niobate waveguide to the shallowly etched thin-film lithium niobate waveguide.

[0071] Specifically, the dielectric layer has a first receiving waveguide at the first end face coupler, the first receiving waveguide matches the first optical fiber mode field, and the first end face coupler includes a first tapered fully etched waveguide and a first tapered half-etched waveguide, so that the light emitted by the first optical fiber is coupled in sequence by the first receiving waveguide, the first tapered fully etched waveguide and the first tapered half-etched waveguide.

[0072] Exemplarily, the first receiving waveguide is matched with the first optical fiber mode field, which means that the light mode distribution transmitted in the first optical fiber matches the size and shape of the first receiving waveguide, that is, the mode field of the first optical fiber matches the geometric shape, mode size, light propagation characteristics, etc. of the first receiving waveguide. In this way, the light in the first optical fiber can be losslessly and effectively coupled to the first receiving waveguide, reducing the loss and reflection during signal transmission.

[0073] Exemplarily, the first tapered fully etched waveguide is a tapered structure with its tip facing the first optical fiber, its width shortens in a direction close to the first optical fiber, and the device layer around the first tapered fully etched waveguide is completely etched away to directly expose the dielectric layer. In other words, the first tapered fully etched waveguide is a tapered waveguide with its tip facing the first optical fiber that is retained after the device layer is partially etched.

[0074] Exemplarily, the first tapered half-etched waveguide is a tapered structure with its tip facing the first optical fiber, its width shortens in a direction close to the first optical fiber, and the device layer around the first tapered half-etched waveguide is partially etched away, and a portion of the device layer is retained, and the dielectric layer is not exposed. The first tapered half-etched waveguide is located on the first tapered fully-etched waveguide, and the tip of the first tapered half-etched waveguide contacts the first tapered fully-etched waveguide, so that the light path can be transmitted from the first tapered fully-etched waveguide to the first tapered half-etched waveguide.

[0075] In other embodiments, the substrate has a second receiving waveguide at the second end face coupler, the second receiving waveguide matches the second optical fiber mode field, and the second end face coupler includes a second tapered fully etched waveguide and a second tapered half-etched waveguide, so that the light emitted by the second optical fiber is coupled by the second receiving waveguide, the second tapered fully etched waveguide, and the second tapered half-etched waveguide in sequence. It can be understood that the positions and corresponding relationships of the second receiving waveguide, the second tapered fully etched waveguide, and the second tapered half-etched waveguide are consistent with the positions and corresponding relationships of the first receiving waveguide, the first tapered fully etched waveguide, and the first tapered half-etched waveguide, and the present application will not repeat them.

[0076] In some embodiments, the photodetector is connected to the microstrip line through an air bridge to transmit the terahertz signal to the microstrip line through the air bridge. An air bridge refers to a conductive structure suspended in the air, which can be used to achieve electrical connection between different electronic components without direct physical contact. Exemplarily, the air bridge can be a thin layer made of a metal material (such as aluminum or copper), suspended in the air, connecting two circuit parts. In this embodiment, one end of the air bridge is connected to the photodetector and the other end is connected to the microstrip line, so that the terahertz signal can be transmitted to the microstrip line through the air bridge.

[0077] See also Figure 5The present application also provides a method for installing a photoelectric detector, comprising the following steps:

[0078] S51, provide a photodetector; provide a target installation structure, the target installation structure includes a substrate, a dielectric layer located on the substrate and a device layer located on the dielectric layer, the device layer has a target installation position and a microstrip line of the photodetector; the device layer includes: a first end face coupler, used to couple the carrier light emitted by the first optical fiber; a second end face coupler, used to couple the local oscillator light emitted by the second optical fiber; a modulation unit, used to modulate the carrier light to obtain signal light; a multi-mode interferometer, used to couple the local oscillator light and the signal light to obtain mixed light; the photodetector is configured on the device layer, used to convert the mixed light into a terahertz signal, and transmit the terahertz signal to the microstrip line; the carrier light, the signal light and the mixed light are respectively transmitted through a transmission waveguide, the device layer is provided with a plurality of grooves, and each transmission waveguide is respectively configured in each groove.

[0079] Exemplarily, the method of mounting a photodetector refers to a method of transferring the photodetector to a target mounting structure.

[0080] Exemplarily, the photodetector may be an InP-based photodetector. Group III-V materials have excellent photoelectric properties, which enable the photodetector to have a large bandwidth and high saturation output power, thereby increasing the signal carrier frequency and signal power.

[0081] S52, forming a plurality of first positioning marks around the target installation position.

[0082] For example, the photodetector needs to be transferred to a target mounting position on the device layer.

[0083] Exemplarily, the first positioning mark may be a metal conductive mark. Further, the metal conductive mark may be gold.

[0084] S53, picking up the photoelectric detector through a transfer stamp, the transfer stamp having a plurality of second positioning marks.

[0085] For example, the transfer stamp may be polydimethylsiloxane (PDMS). Based on the micro-transfer technology, the photodetector is picked up using the transfer stamp with the second positioning mark, so that the photodetector is located at a preset position of the transfer stamp.

[0086] S54, aligning each first positioning mark and each second positioning mark so that the transfer stamp is located at the target installation position.

[0087] Exemplarily, the transfer stamp carries a photodetector, and by moving the position of the transfer stamp, each second positioning mark on the transfer stamp corresponds to each first positioning mark, which indicates that the photodetector is relative to the grating.

[0088] Accurate alignment of the photodetector and the grating can ensure that the photodetector can receive the light signal from the grating, thereby effectively performing optical detection and signal conversion.

[0089] S55, removing the transfer stamp, forming an air bridge, and connecting the photodetector and the microstrip line through the air bridge.

[0090] In the above-mentioned method for installing a photodetector, the photodetector is installed at a target installation position on a target installation structure, and the target installation structure includes a substrate, a dielectric layer located on the substrate, and a device layer located on the dielectric layer; the device layer includes a target installation position and a microstrip line. First, a plurality of first positioning marks are formed around the target installation position, and then the photodetector is picked up by a transfer stamp with a second positioning mark. After aligning the first positioning mark and the second positioning mark, it indicates that the photodetector is transferred to the target installation position, and the transfer stamp can be removed. The method for installing a photodetector provided in the present application provides a heterogeneous integration solution. In the case where the materials of the photodetector and the device layer are different, heterogeneous integration can be achieved by using the installation method provided in the present application.

[0091] In some embodiments, aligning each first positioning mark with each second positioning mark in step S54 includes:

[0092] S541, simultaneously acquiring a first image of the photonic terahertz communication transmitting device and a second image of the transfer stamp, wherein the first image includes at least a first positioning mark, and the second image includes at least a second positioning mark, and based on an image recognition algorithm, acquiring spatial position information of the first positioning mark and the second positioning mark.

[0093] Exemplarily, the image recognition algorithm identifies the positions of the first positioning mark and the second positioning mark through an edge detection model.

[0094] S542, based on the projection transformation algorithm, determine the projection position of the second positioning mark on the device layer, and determine the relative position relationship between the projection position and the first positioning mark.

[0095] Exemplarily, through the projection transformation algorithm, the second positioning mark in the three-dimensional space can be projected onto the image plane and compared with the projection position of the first positioning mark to calculate the relative position relationship such as translation, rotation or scale transformation between them.

[0096] S543, adjusting the position of the transfer stamp based on the relative position relationship so that the projection position coincides with the first positioning mark, thereby achieving alignment of the first positioning mark and the second positioning mark.

[0097] In this embodiment, an image recognition algorithm and a projection transformation algorithm are used to determine the positions of the first positioning mark and the second positioning mark, so as to achieve precise alignment of the photoelectric detector and the photonic terahertz communication transmitting device.

[0098] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features of the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0099] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A photon terahertz communication transmitting device, characterized in that: The photon terahertz communication transmitting device comprises a substrate, a dielectric layer located on the substrate, a device layer located on the dielectric layer, and a photodetector; the device layer comprises: A first end face coupler, used for coupling the carrier light emitted by the first optical fiber; A second end face coupler, used for coupling the local oscillator light emitted by the second optical fiber; A modulation unit, used for modulating the carrier light to obtain a signal light; A multi-mode interferometer, used for coupling the local oscillator light and the signal light to obtain mixed frequency light; The photodetector is configured on the device layer, and is used to convert the mixed frequency light into a terahertz signal, and transmit the terahertz signal to a microstrip line; The carrier light, the local oscillator light, the signal light, and the mixed frequency light are respectively transmitted through transmission waveguides, the device layer is provided with a plurality of grooves, and each of the transmission waveguides is respectively arranged in each of the grooves.

2. The photon terahertz communication transmitting device according to claim 1, characterized in that: The modulation unit includes a modulator, which is a coherent modulator composed of an I-channel modulator and a Q-channel modulator, the I-channel modulator includes a first optical waveguide and a first radio frequency electrode, the Q-channel modulator includes a second optical waveguide and a second radio frequency electrode, the difference between a propagation refractive index of the first radio frequency electrode and a propagation refractive index of the first optical waveguide is within a preset range, and / or the difference between a propagation refractive index of the second radio frequency electrode and a propagation refractive index of the second optical waveguide is within a preset range.

3. The photon terahertz communication transmitting device according to claim 2, characterized in that: The modulation unit also includes: A first beam splitter, used for splitting the carrier light into a first sub-carrier light and a second sub-carrier light; A second beam splitter, used for splitting the first branched carrier light into two paths and inputting the two paths into the I-path modulator, and modulating the I-path modulator to obtain an I-path modulated signal; A third beam splitter, used for splitting the second sub-carrier light into two paths and inputting the two paths into the Q-path modulator, and modulating the two paths by the Q-path modulator to obtain a Q-path modulated signal; A beam combiner is used to combine the I-channel modulated signal with the Q-channel modulated signal to obtain the signal light.

4. The photon terahertz communication transmitting device according to claim 2, characterized in that: A thermal image shifter is provided at the signal input end of the optical waveguide in the I-channel modulator; and / or, The signal input end and the signal output end of the optical waveguide in the Q-path modulator are both provided with thermal image shifters.

5. The photon terahertz communication transmitting device according to claim 2, characterized in that: In the I-channel modulator and / or the Q-channel modulator, the radio frequency electrode is located on the side of the optical waveguide, and the radio frequency electrode is a periodic T-shaped track traveling wave electrode.

6. The photon terahertz communication transmitting device according to claim 1, characterized in that: The dielectric layer has a first receiving waveguide at the first end face coupler, the first receiving waveguide matches the first optical fiber mode field, the first end face coupler includes a first tapered fully etched waveguide and a first tapered half-etched waveguide, so that the light emitted by the first optical fiber is coupled by the first receiving waveguide, the first tapered fully etched waveguide and the first tapered half-etched waveguide in sequence; and / or, The dielectric layer has a second receiving waveguide at the second end face coupler, and the second receiving waveguide matches the second optical fiber mode field. The second end face coupler includes a second tapered fully etched waveguide and a second tapered half-etched waveguide, so that the light emitted by the second optical fiber is coupled in sequence by the second receiving waveguide, the second tapered fully etched waveguide and the second tapered half-etched waveguide.

7. The photon terahertz communication transmitting device according to claim 1, characterized in that: The substrate is made of silicon, the dielectric layer is made of silicon oxide, the device layer is a lithium niobate film, and the transmission waveguide is made of lithium niobate.

8. The photon terahertz communication transmitting device according to claim 1, characterized in that: The photodetector is connected to the microstrip line via an air bridge, so as to transmit the terahertz signal to the microstrip line via the air bridge.

9. A method for installing a photoelectric detector, characterized in that: The following steps are involved: Providing a photodetector; A target mounting structure is provided, the target mounting structure comprising a substrate, a dielectric layer located on the substrate, and a device layer located on the dielectric layer, the device layer having a target mounting position of the photodetector and a microstrip line; the device layer comprising: a first end face coupler for coupling a carrier light emitted by a first optical fiber; a second end face coupler for coupling a local oscillator light emitted by a second optical fiber; a modulation unit for modulating the carrier light to obtain a signal light; a multimode interferometer for coupling the local oscillator light and the signal light to obtain a mixed-frequency light; the photodetector is arranged on the device layer, and is used to convert the mixed-frequency light into a terahertz signal, and transmit the terahertz signal to the microstrip line; the carrier light, the signal light, and the mixed-frequency light are respectively transmitted through a transmission waveguide, the device layer is provided with a plurality of grooves, and each of the transmission waveguides is respectively arranged in each of the grooves; forming a plurality of first positioning marks around the target installation position; picking up the photodetector by a transfer stamp having a plurality of second positioning marks thereon; Aligning each of the first positioning marks with each of the second positioning marks so that the transfer stamp is located at the target installation position; The transfer stamp is removed to form an air bridge, and the photodetector and the microstrip line are connected via the air bridge.

10. The method for installing a photoelectric detector according to claim 9, characterized in that: The aligning each of the first positioning marks and each of the second positioning marks comprises: Acquire a first image of the photon terahertz communication transmitting device and a second image of the transfer stamp, wherein the first image includes at least the plurality of first positioning marks, and the second image includes at least the plurality of second positioning marks, and acquire spatial position information of the first positioning marks and the second positioning marks based on an image recognition algorithm; Based on a projection transformation algorithm, determining a projection position of the second positioning mark on the device layer, and determining a relative positional relationship between the projection position and the first positioning mark; The position of the transfer stamp is adjusted based on the relative position relationship so that the projection position coincides with the first positioning mark, so as to achieve alignment of the first positioning mark and the second positioning mark.

Images