Photon wireless signal generation system for eliminating laser phase noise and preparation method of chip

Abstract

The invention discloses a photon wireless signal generation system capable of eliminating laser phase noise and a preparation method, and the technical key points are that the photon wireless signal generation system is integrated on an I nP-based photoelectric chip, the photon wireless signal generation system comprises a laser, the output end of the laser is connected with the input end of an RF modulation unit, the output end of the RF modulation unit is connected with the input end of a wavelength selection unit, and the wavelength selection unit is connected with the I nP-based photoelectric chip. The first output end of the wavelength selection unit is connected with the input end of the data modulation unit, the output end of the data modulation unit is connected with the first input end of the optical coupler, the second output end of the wavelength selection unit is connected with the second input end of the optical coupler, and the output end of the optical coupler is connected with the input end of the optical amplifier. The output end of the optical amplifier is in optical coupling connection with the photoelectric detector, and the output end of the photoelectric detector is connected with the input end of the antenna. The system is based on an I nP-based photoelectric platform, the system complexity is low, the integration level is high, preparation is easy, the performance and frequency stability of photon wireless signals are improved, and the error rate of a wireless communication system is reduced.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a photon wireless signal generation system for eliminating laser phase noise and a chip preparation method. Background Art

[0002] In the current Internet era, global data traffic is growing exponentially, and the demand for the development of ultra-high-speed communications is becoming increasingly urgent. Terahertz communication has become one of the key technologies for the next generation of ultra-high-speed wireless communications due to its huge available bandwidth resources. According to the generation method of terahertz signals, terahertz communication systems are divided into two categories: electronic systems and photon-assisted systems. The transmission power of electronic systems is high and can support long-distance wireless transmission, but their harmonic interference, phase noise, and frequency deviation are large. Affected by the working bandwidth and modulation efficiency of electronic devices, the capacity of pure electronic systems is limited. The typical system of photon-assisted terahertz wireless communication uses an electro-optical modulator to modulate the baseband signal onto an optical carrier, and then generates a terahertz signal through an optical heterodyne method, which can achieve ultra-high-speed wireless communication. In addition, the photon-assisted terahertz wireless communication system combines radio frequency over fiber (RoF) technology, which can be seamlessly integrated with the existing optical fiber network, share urban infrastructure, and greatly reduce the cost of network upgrades.

[0003] In the prior art, typical photon-assisted terahertz wireless communication systems use methods such as optical injection locking, optical phase-locked loop, and optical injection phase-locked loop to reduce the impact of random phase noise of the laser. Although these improvement schemes can suppress the impact of phase noise on system performance to a certain extent, they are difficult to implement on a large scale due to the complexity of the adopted system and high requirements on equipment performance. The optical heterodyne method, which is easier to implement, is seriously affected by the phase noise of the two lasers. The phase and amplitude between the two lasers are difficult to control, and the generated electromagnetic wave wireless signal contains phase noise, resulting in poor frequency stability and quality. Summary of the invention

[0004] In view of the problems existing in the prior art, the first object of the present invention is to provide a photon wireless signal generation system that eliminates laser phase noise, which is characterized by being based on an I nP-based optoelectronic platform, having low system complexity, high integration, and easy preparation, thereby improving the performance and frequency stability of the photon wireless signal and reducing the bit error rate of the wireless communication system.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a photon wireless signal generation system for eliminating laser phase noise, integrated on an I nP-based optoelectronic chip, the system comprising: a laser, an RF modulation unit, a wavelength selection unit, a data modulation unit, an optical coupler, an optical amplifier, a photodetector and an antenna, the output end of the laser is connected to the input end of the RF modulation unit, the output end of the RF modulation unit is connected to the input end of the wavelength selection unit, the first output end of the wavelength selection unit is connected to the input end of the data modulation unit, the output end of the data modulation unit is connected to the first input end of the optical coupler, the second output end of the wavelength selection unit is connected to the second input end of the optical coupler, the output end of the optical coupler is connected to the input end of the optical amplifier, the output end of the optical amplifier is optically coupled to the photodetector, and the output end of the photodetector is connected to the input end of the antenna; wherein,

[0006] The RF modulation unit is used to modulate the basic optical signal emitted by the laser to form a sideband signal;

[0007] The wavelength selection unit is used to select two optical signals with a frequency difference of terahertz frequency band from the sideband signal;

[0008] The data modulation unit is used to load the data baseband signal to be transmitted onto one of the optical signals output by the wavelength selection unit to form a data carrier optical signal;

[0009] The optical coupler is used to combine the data carrier optical signal and the local oscillator optical signal into a coupled optical signal;

[0010] The optical amplifier is used to amplify the coupled optical signal after beam combining;

[0011] The above-mentioned photodetector is used to convert the amplified coupled optical signal into an electrical signal in the terahertz frequency band;

[0012] The above antenna is used to convert electrical signals in the terahertz frequency band into terahertz radio electromagnetic wave signals and radiate them out.

[0013] Furthermore, the RF modulation unit includes a first modulator and an RF signal generator, wherein the RF signal generator is used to generate an RF signal of a given frequency, and the signal output end of the RF generator is connected to the modulation end of the first modulator to load the RF signal of the given frequency to the first modulator; the basic optical signal passes through the first modulator and is modulated by the RF signal of the given frequency to form multiple sideband signals with a frequency difference of a given frequency.

[0014] Furthermore, the first modulator adopts an InP-based MZM modulator or a micro-ring resonator.

[0015] Furthermore, the wavelength selection unit is a filter or a wavelength selector.

[0016] Furthermore, the data modulation unit includes a second modulator, a modulation end of the second modulator receives a data baseband signal to be transmitted, and loads the data baseband signal to be transmitted onto a carrier optical signal to form a carrier optical signal.

[0017] Furthermore, the second modulator adopts an InP-based MZM modulator or a micro-ring resonator.

[0018] Furthermore, the optical coupler is a Y coupler or an MMI coupler.

[0019] Furthermore, the optical amplifier is a semiconductor optical amplifier.

[0020] Furthermore, the above-mentioned photodetector is a single-row carrier photodetector.

[0021] The second object of the present invention is to provide a method for preparing a photon wireless signal generating chip for eliminating laser phase noise, comprising the following steps:

[0022] Providing an I nP substrate;

[0023] Growing an epitaxial structure on the above-mentioned InP substrate to form a wafer epitaxial wafer;

[0024] A wafer with a waveguide structure is formed on the above-mentioned wafer epitaxial wafer by photolithography and etching; the wafer with a waveguide structure includes a waveguide structure of a laser, a waveguide structure of an RF modulation unit, a waveguide structure of a wavelength selection unit, a waveguide structure of a data modulation unit, a waveguide structure of an optical coupler, a waveguide structure of an optical amplifier, a waveguide structure of a photodetector and a waveguide structure of an antenna, and a plurality of optical transmission waveguides; wherein the output end of the laser is connected to the input end of the RF modulation unit through the optical transmission waveguide, the output end of the RF modulation unit is connected to the input end of the wavelength selection unit through the optical transmission waveguide, the first output end of the wavelength selection unit is connected to the input end of the data modulation unit through the optical transmission waveguide, the output end of the data modulation unit is connected to the first input end of the optical coupler through the optical transmission waveguide, the second output end of the wavelength selection unit is connected to the second input end of the optical coupler through the optical transmission waveguide, the output end of the optical coupler is connected to the input end of the optical amplifier through the optical transmission waveguide, and the output end of the optical amplifier is connected to the photodetector through the optical transmission waveguide;

[0025] Doping is performed on the wafer having the waveguide structure to form PN junctions of lasers, optical amplifiers and photodetectors;

[0026] Electrodes, metal interconnects and antennas are prepared, and the output electrode of the photodetector is connected to the input end of the antenna using the metal interconnects.

[0027] The invention has the beneficial effects of providing a terahertz wireless signal generation system based on optical heterodyne method and a preparation method thereof, which is based on an I nP-based optoelectronic platform, has low system complexity, high integration, and is easy to prepare. The system of the invention uses a single laser to generate two optical signals with a frequency difference of terahertz frequency band by a modulator or a microring resonator combined with a wavelength selection unit, and since the above two optical signals are both from the same laser, the phase correlation between the two optical signals is very strong, and the phases between the two optical signals can cancel each other after heterodyne mixing in a photodetector, avoiding the influence of phase noise between different lasers, thereby improving the performance and frequency stability of photon wireless signals, and reducing the bit error rate of the wireless communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural diagram of an existing photon terahertz wireless signal system realized by heterodyne method;

[0029] Figure 2 A structural diagram of a photon wireless signal generating system according to an embodiment of the present invention;

[0030] FIG3( a ) is a spectrum diagram of an optical signal after RF modulation;

[0031] FIG3( b) is a spectrum diagram of an optical signal output by a wavelength selection unit;

[0032] FIG3( c ) is a spectrum diagram of another optical signal output by the wavelength selection unit;

[0033] FIG3( d ) is a spectrum diagram of the coupled optical signal output by the optical coupler;

[0034] Figure 4 It is the spectrum diagram of the electrical signal output by the photodetector;

[0035] Figure 5 This is a structural diagram of the photon wireless signal generation chip of the present invention;

[0036] Figure 6 This is a flow chart of the method for preparing the photon wireless signal generating chip of the present invention.

[0037] Figure numerals: 1. laser; 2. RF modulation unit; 21. RF signal generator; 22. first modulator; 3. wavelength selection unit; 4. data modulation unit; 5. optical coupler; 6. optical amplifier; 7. photodetector; 8. antenna; 9. optical transmission waveguide; 10. metal interconnection line; 11. photonic wireless transmission system chip. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the drawings, and the words "bottom" and "top", "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0041] Existing photonic terahertz wireless signal generation systems are mainly implemented using the heterodyne method. Figure 1 As shown, two lasers with output light frequencies of f1 and f2 are used. For the convenience of discussion, the laser with output light frequency of f1 is called laser No. 1, and the laser with output light frequency of f2 is called laser No. 2, where f1>f2. The baseband signal is loaded onto the output light wave of laser No. 1 through an external modulator, and the two light wave signals emitted by the two lasers are combined into one optical path by a coupler, and then amplified by an optical amplifier. After the photodetector converts the amplified light signal into an electrical signal, the electrical signal is converted into a radio electromagnetic wave signal and radiated out through a high-gain antenna interconnected with the photodetector.

[0042] Assume that the electric field distributions of the two light wave signals are:

[0043]

[0044]

[0045] E1 and E2 are the amplitudes of the two light wave signals, f1 and f2 are the frequencies of the two light wave signals, are the initial phases of the two light wave signals respectively. Then the photocurrent of the photoelectric detection is:

[0046]

[0047] From the above formula, it can be seen that the frequency of the electromagnetic wave wireless signal is the frequency difference of the two light wave signals, and the power is proportional to the light intensity of the two lasers. By adjusting the laser frequency, the wireless signal frequency can be continuously regulated, which is larger than the adjustment range of electronic devices. In addition, it can be found from the above formula that the electromagnetic wave wireless signal generated will have phase noise caused by and, which will have a great impact on the performance of the system. Phase noise refers to the random fluctuation of the phase of the laser output optical signal over time. This fluctuation is usually caused by various noise sources inside the laser (such as thermal noise, electronic noise, photon noise, etc.).

[0048] Since the ordinary optical heterodyne method is seriously affected by the phase noise of the two lasers, the phase and amplitude between the two lasers are difficult to control, and the generated electromagnetic wave wireless signal contains phase noise, resulting in poor frequency stability and quality. For this reason, people have proposed methods such as optical injection locking, optical phase-locked loop, and optical injection phase-locked loop to reduce the impact of random phase noise of the laser. Although these improvement schemes have suppressed the impact of phase noise on system performance to a certain extent, they are difficult to implement on a large scale due to the complexity of the system used and the high performance requirements of the equipment.

[0049] In view of the above problems, the present invention designs a photon wireless signal generation system for eliminating laser phase noise, such as Figure 2 As shown, the system includes a laser, an RF modulation unit, a wavelength selection unit, a data modulation unit, an optical coupler, an optical amplifier, a photodetector and an antenna, and the system is integrated on an I nP-based optoelectronic chip. The output end of the laser is connected to the input end of the RF modulation unit, the output end of the RF modulation unit is connected to the input end of the wavelength selection unit, the first output end of the wavelength selection unit is connected to the input end of the data modulation unit, the output end of the data modulation unit is connected to the first input end of the optical coupler, the second output end of the wavelength selection unit is connected to the second input end of the optical coupler, the output end of the optical coupler is connected to the input end of the optical amplifier, the output end of the optical amplifier is optically coupled to the photodetector, and the output end of the photodetector is connected to the input end of the antenna.

[0050] Specifically, the output end of the above-mentioned laser is optically coupled to the input end of the RF modulation unit, the output end of the RF modulation unit is optically coupled to the input end of the wavelength selection unit, the first output end of the wavelength selection unit is optically coupled to the input end of the data modulation unit, the output end of the data modulation unit is optically coupled to the first input end of the optical coupler, the second output end of the wavelength selection unit is optically coupled to the second input end of the optical coupler, the output end of the optical coupler is optically coupled to the input end of the optical amplifier, the output end of the optical amplifier is optically coupled to the photodetector, and the output end of the photodetector is electrically connected to the input end of the antenna.

[0051] The above-mentioned laser is used to transmit a basic optical signal; in practice, the laser may be a DFB laser, a VCSEL laser, a DBR laser, etc.;

[0052] The RF modulation unit modulates the basic optical signal emitted by the laser based on an RF signal of a given frequency to form a sideband signal;

[0053] The wavelength selection unit is used to select two optical signals with a frequency difference of terahertz frequency band from the sideband signal. By controlling the frequencies of the two optical signals output by the wavelength selection unit, the frequency of the optically-carried terahertz wireless signal can be regulated. For the convenience of discussion, the two optical signals with a frequency difference of terahertz frequency band are respectively referred to as carrier optical signals and local oscillator optical signals;

[0054] The data modulation unit is used to load the data baseband signal to be transmitted onto the carrier optical signal to form a data carrier optical signal;

[0055] The optical coupler is used to combine the data carrier optical signal and the local oscillator optical signal into a coupled optical signal;

[0056] The optical amplifier is used to amplify the coupled optical signal after beam combining;

[0057] The above-mentioned photodetector is used to convert the amplified optical signal into an electrical signal in the terahertz frequency band;

[0058] The above antenna is used to convert electrical signals in the terahertz frequency band into terahertz radio electromagnetic wave signals and radiate them out.

[0059] In the embodiment of the present invention, firstly, a frequency of f is used THz / 2 local oscillator (f THz The laser with the center frequency f is modulated by the wavelength selection unit, and the center frequencies ff and THz / 2 and f+f THz / 2 two sideband signals. Among them, the data to be sent is modulated on one of the sideband signals, and then combined with the other sideband signal into one signal through an optical coupler. The combined optical signal is amplified by an optical amplifier, and then transmitted to a photodetector through an optical waveguide or fiber. Finally, the heterodyne mixing of the photodetector generates a frequency of f THz The electrical signal is then transmitted to f through a high-gain antenna THz The electrical signal is converted into a carrier frequency of f THz The radio electromagnetic wave signal is radiated into free space.

[0060] Since the present invention uses a single laser combined with a wavelength selection unit to generate a carrier optical signal and a local oscillator optical signal, the initial phases of the two or more optical signals are the same (φ1=φ2), which is equivalent to Figure 1 The initial phases of the two different lasers in the system are the same, and then after heterodyne mixing occurs at the photodetector, the phases of the two optical signals cancel each other out, so the noise of the photon wireless signal system generated by a single laser is much smaller than that of the two laser systems. In addition, since the two optical signals generated by a single laser are heterodyne mixed, there is no problem of frequency drift caused by the frequency disturbance generated by two different lasers, so the quality of the photon wireless signal after heterodyne mixing will be better, thereby improving the transmission performance of the photon terahertz wireless communication system.

[0061] The carrier frequency f of terahertz is THz =200GHz, that is, the RF signal loaded on the first modulator is f THz / 2=100GHz, the center frequency of the laser f=193.1THz and the initial power 10dBm, and the transmission rate of the data baseband signal loaded on the second modulator is 25Gbit / s as an example for detailed description. Figure 4 for Figure 2 Spectrum diagram of the photon wireless signal generating system in the actual application process of this embodiment, wherein FIG3(a) corresponds to Figure 2 The spectrum of the optical signal at A in FIG3(b) corresponds to Figure 2 The spectrum of the optical signal at C in Figure 3(c) corresponds to Figure 2 The spectrum of the optical signal at B in FIG3( d ) corresponds to Figure 2 The spectrum of the optical signal at D in the figure, Figure 4 Corresponds to Figure 1The electrical signal spectrum diagram of the optical signal at E in the figure. Specifically, the spectrum diagram of the laser with a center frequency of 193.1THz after passing through the first modulator and being modulated by the 100GHz RF signal is shown in Figure 3(a). After the 100GHz RF signal passes through the first modulator, the optical signal is modulated into multiple sideband signals with a frequency difference interval of 100GHz with a center frequency of 193.1THz. After being processed by the corresponding wavelength selection unit, two optical signals with center frequencies of 193.2THz and 193THz can be obtained, as shown in Figure 3(b) and Figure 3(c). The 25Gb it / s data baseband signal to be transmitted is loaded onto the optical signal of the optical path with a center frequency of 193THz through modulator 2. As can be seen from Figure 3(c), this optical signal already carries 25Gb it / s data information. As shown in FIG3( d ), the two optical signals are combined into one optical signal after optical coupling, one of which carries the data baseband signal to be transmitted, and the frequency difference between the two optical signals is 200 GHz. Figure 4 The figure shows the spectrum of the electrical signal obtained by combining the two optical signals and converting the combined coupled optical signals through the optical amplifier and the photodetector. As can be seen from the figure, after the two optical signals are frequency-differencing through the photodetector, the carrier frequency is down-converted from the 193THz of the optical signal to the 200GHz of the electrical signal. After the electrical signal passes through the high-gain antenna, the 200GHz electrical signal carrying data information can be converted into a radio electromagnetic wave signal for wireless transmission in space.

[0062] In a specific embodiment, the RF modulation unit includes a first modulator and an RF signal generator, wherein the RF signal generator is used to generate an RF signal of a given frequency, and the signal output end of the RF generator is connected to the modulation end of the first modulator, and the RF signal of the given frequency is loaded to the first modulator. After the basic optical signal passes through the first modulator and is modulated by the RF signal of the given frequency, a plurality of sideband signals with a frequency difference of the given frequency are formed.

[0063] In some specific embodiments, the wavelength selection unit is a filter or a wavelength selector. The function of the filter or the wavelength selector is to select two optical signals with a frequency difference in the terahertz frequency band from multiple sideband signals, namely, the carrier optical signal and the local oscillator optical signal. In practice, the wavelength selection unit can be implemented by using an optical waveguide filter, an optical waveguide array filter, etc. known in the art. For example, the wavelength selection unit is a microring resonator structure. By adjusting parameters such as the radius of the microring resonator or the width of the waveguide, the frequency selection of the optical signal can be achieved.

[0064] In a specific embodiment, the data modulation unit includes a second modulator, the modulation end of the second modulator receives the data baseband signal to be transmitted, and loads the data baseband signal to be transmitted onto the carrier optical signal to form the carrier optical signal. In practice, the data modulation unit can be implemented by an on-chip modulator, an on-chip modulator array, etc. known in the art. For example, the first modulator and the second modulator can be implemented by a microring resonator modulator or an MZM modulator.

[0065] In a specific embodiment, the optical coupler is a Y coupler or an MMI coupler.

[0066] In a specific embodiment, the optical amplifier is a semiconductor optical amplifier (SOA).

[0067] In a specific embodiment, the photodetector is a single-track carrier photodetector (UTC-PD).

[0068] In a specific embodiment, the antenna is a planar antenna. Specifically, the antenna has a high gain property.

[0069] like Figure 5 As shown, when the laser adopts a DFB laser, the first modulator of the RF modulation unit adopts an I nP-based MZM modulator or a microring resonant modulator / the RF modulation unit is a microring resonator, the data selection unit adopts an I nP-based MZM modulator or a microring resonant modulator, the wavelength selector adopts a waveguide microring structure, the optical coupler adopts a Y branch or an MMI coupler structure, the optical amplifier adopts a semiconductor optical amplifier structure, the photodetector adopts a single-row carrier photodetector, and the antenna adopts a planar antenna structure, the system of the present invention can be prepared on an I nP base. Since these devices can be integrated together through I nP-based epitaxy or chip flip-chip bonding, the above scheme can realize the integration and preparation of the photon wireless transmission system chip 11 with the help of an I nP optoelectronic platform.

[0070] Compared with the traditional photonic terahertz wireless communication system based on discrete devices, the on-chip photonic terahertz chip implemented by the above-mentioned InP-based integration scheme has the advantages of small size, low power consumption and high integration. Compared with the traditional optical frequency comb system, it uses fewer components, has a simpler system structure and less additional noise.

[0071] Of course, the embodiments of the present invention are not limited to the above embodiments, and can also be appropriately adjusted and changed according to actual needs. For example, the number of devices in the system can be increased or decreased, or the type of devices can be changed, etc., to adapt to different application scenarios.

[0072] The present invention also designs a method for preparing a photon wireless signal generation chip for eliminating laser phase noise, such as Figure 6As shown, the specific steps are as follows:

[0073] S1: Provide an I nP substrate;

[0074] S2: growing an epitaxial structure on the I nP substrate to form a wafer epitaxial wafer;

[0075] S3: Forming a wafer with a waveguide structure on the wafer epitaxial wafer by photolithography and etching. Figure 5 As shown, the wafer with a waveguide structure includes a waveguide structure of a laser, a waveguide structure of an RF modulation unit, a waveguide structure of a wavelength selection unit, a waveguide structure of a data modulation unit, a waveguide structure of an optical coupler, a waveguide structure of an optical amplifier, a waveguide structure of a photodetector and an antenna structure, and a plurality of optical transmission waveguides; wherein the output end of the laser is connected to the input end of the RF modulation unit through the optical transmission waveguide, the output end of the RF modulation unit is connected to the input end of the wavelength selection unit through the optical transmission waveguide, the first output end of the wavelength selection unit is connected to the input end of the data modulation unit through the optical transmission waveguide, the output end of the data modulation unit is connected to the first input end of the optical coupler through the optical transmission waveguide, the second output end of the wavelength selection unit is connected to the second input end of the optical coupler through the optical transmission waveguide, the output end of the optical coupler is connected to the input end of the optical amplifier through the optical transmission waveguide, and the output end of the optical amplifier is optically coupled to the photodetector through the optical transmission waveguide;

[0076] S4: doping is performed on the wafer with the waveguide structure to form PN junctions of lasers, optical amplifiers and photodetectors;

[0077] S5: Prepare electrodes, metal interconnects and antennas. Figure 5 As shown, the electrode includes an output electrode of a photodetector, and a metal interconnection line is used to connect the output electrode of the photodetector to the input end of the antenna.

[0078] Specifically, InP The substrate includes an InP layer, an insulating layer and an InP base layer.

[0079] Specifically, the InP-based epitaxial structure includes at least an epitaxial buffer layer, an epitaxial multi-quantum well layer and an epitaxial doping layer. In practice, the epitaxial structure can be grown on the InP substrate using methods such as chemical vapor deposition (CVD) or molecular beam epitaxy (MBE).

[0080] Specifically, a wafer with a waveguide structure is formed by photolithography and etching, including the following steps: coating a photoresist on the wafer, then forming a photoresist pattern with a waveguide structure by photolithography technology, and then transferring the photoresist pattern to the wafer by etching technology to form a wafer with a waveguide structure.

[0081] Specifically, the doping method includes ion implantation, diffusion, and the like.

[0082] Specifically, the method for preparing electrodes, metal interconnects and antennas includes: coating photoresist on a wafer, then forming photoresist patterns of electrodes, metal interconnects and antennas through photolithography and etching techniques, and then transferring the metal patterns to the wafer through evaporation, stripping and ion stripping techniques to form electrodes, metal interconnects and antennas.

[0083] In summary, the present invention provides a terahertz wireless signal generation system based on optical heterodyne method, which is based on InP-based optoelectronic platform, has low system complexity, high integration, and is easy to prepare. The system of the present invention uses a single laser to generate a carrier optical signal and a local oscillator optical signal through a modulator or a microring resonator combined with a wavelength selection unit. Since the carrier optical signal and the local oscillator optical signal are both from the same laser, the phase correlation between the two optical signals is very strong. After heterodyne mixing in the photodetector, the phases between the two optical signals can cancel each other, avoiding the influence of phase noise between different lasers, thereby improving the performance and frequency stability of the photon wireless signal and reducing the bit error rate of the wireless communication system.

[0084] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the invention may be modified or replaced by equivalents without departing from the scope of the technical solutions of the present invention, which should all be covered by the scope of the claims of the present invention.

Claims

1. A photon wireless signal generation system for eliminating laser phase noise, characterized in that: Integrated on an InP-based optoelectronic chip, the system includes: a laser, an RF modulation unit, a wavelength selection unit, a data modulation unit, an optical coupler, an optical amplifier, a photodetector and an antenna, the output end of the laser is connected to the input end of the RF modulation unit, the output end of the RF modulation unit is connected to the input end of the wavelength selection unit, the first output end of the wavelength selection unit is connected to the input end of the data modulation unit, the output end of the data modulation unit is connected to the first input end of the optical coupler, the second output end of the wavelength selection unit is connected to the second input end of the optical coupler, the output end of the optical coupler is connected to the input end of the optical amplifier, the output end of the optical amplifier is optically coupled to the photodetector, and the output end of the photodetector is connected to the input end of the antenna; wherein, The RF modulation unit is used to modulate the basic optical signal emitted by the laser to form a sideband signal; The wavelength selection unit is used to select two optical signals with a frequency difference of terahertz frequency band from the sideband signal; The data modulation unit is used to load the data baseband signal to be transmitted onto one of the optical signals output by the wavelength selection unit to form a data carrier optical signal; The optical coupler is used to combine the data carrier optical signal and the local oscillator optical signal into a coupled optical signal; The optical amplifier is used to amplify the combined optical signal; The photodetector is used to convert the amplified coupled optical signal into an electrical signal in the terahertz frequency band; The antenna is used to convert the electrical signal in the terahertz frequency band into a terahertz radio electromagnetic wave signal and radiate it out.

2. The photon wireless signal generating system according to claim 1, characterized in that: The RF modulation unit includes a first modulator and an RF signal generator, wherein the RF signal generator is used to generate an RF signal of a given frequency, and the signal output end of the RF generator is connected to the modulation end of the first modulator to load the RF signal of the given frequency to the first modulator; the basic optical signal passes through the first modulator and is modulated by the RF signal of the given frequency to form multiple sideband signals with a frequency difference of the given frequency.

3. The photon wireless signal generating system according to claim 2, characterized in that: The first modulator adopts an InP-based MZM modulator or a micro-ring resonator.

4. The method according to claim 1, characterized in that: The wavelength selection unit is a filter or a wavelength selector.

5. According to any one of claims 1 to 4, it is characterized in that: The data modulation unit includes a second modulator, a modulation end of the second modulator receives a data baseband signal to be transmitted, and loads the data baseband signal to be transmitted onto a carrier optical signal to form a carrier optical signal.

6. The photon wireless signal generating system according to claim 5, characterized in that: The second modulator adopts an InP-based MZM modulator or a micro-ring resonator.

7. The photon wireless signal generating system according to claim 1, characterized in that: The optical coupler is a Y coupler or an MMI coupler.

8. The photon wireless signal generating system according to claim 1, characterized in that: The optical amplifier is a semiconductor optical amplifier.

9. The photon wireless signal generating system according to claim 1, characterized in that: The photoelectric detector is a single-row carrier photoelectric detector.

10. A method for preparing a photon wireless signal generation chip for eliminating laser phase noise, used for preparing a photon wireless signal generation system as claimed in claims 1 to 9, characterized in that: The steps include: Providing an InP substrate; Growing an epitaxial structure on the InP substrate to form a wafer epitaxial wafer; A wafer with a waveguide structure is formed on the wafer epitaxial wafer by photolithography and etching; the wafer with a waveguide structure includes a waveguide structure of a laser, a waveguide structure of an RF modulation unit, a waveguide structure of a wavelength selection unit, a waveguide structure of a data modulation unit, a waveguide structure of an optical coupler, a waveguide structure of an optical amplifier, a waveguide structure of a photodetector and a waveguide structure of an antenna, and a plurality of optical transmission waveguides; wherein the output end of the laser is connected to the input end of the RF modulation unit through the optical transmission waveguide, the output end of the RF modulation unit is connected to the input end of the wavelength selection unit through the optical transmission waveguide, the first output end of the wavelength selection unit is connected to the input end of the data modulation unit through the optical transmission waveguide, the output end of the data modulation unit is connected to the first input end of the optical coupler through the optical transmission waveguide, the second output end of the wavelength selection unit is connected to the second input end of the optical coupler through the optical transmission waveguide, the output end of the optical coupler is connected to the input end of the optical amplifier through the optical transmission waveguide, and the output end of the optical amplifier is connected to the photodetector through the optical transmission waveguide; Doping is performed on the wafer having the waveguide structure to form PN junctions of a laser, an optical amplifier and a photodetector; Fabrication of electrodes, metal interconnects and antennas.

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