CN112485777A

CN112485777A - Light-controlled microwave phased array radar system based on pluggable receiving and transmitting assembly and feedback control method

Info

Publication number: CN112485777A
Application number: CN202011305703.7A
Authority: CN
Inventors: 程齐曼; 张强; 余辉; 章献民
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2020-11-19
Filing date: 2020-11-19
Publication date: 2021-03-12
Anticipated expiration: 2040-11-19
Also published as: CN112485777B

Abstract

The invention discloses an optically controlled microwave phased array radar system and a feedback control method based on pluggable transceiver components. The technical solution adopted in the present invention is to use a variety of material platforms to realize photonic integrated chips with different functions, through the coupling technology between optical chips, interconnect multiple chips to realize all-optical integrated transceiver components, and use flip-chip or wire-bonding at the same time. The technology encapsulates the control electronic chip and the optical chip component in the same tube, and finally obtains the pluggable transceiver component and the optical control phased array radar system composed of it. The microwave phased array radar component of the present invention is constructed based on an optical chip, has strong anti-electromagnetic interference capability, and improves the signal transmission capacity at the same time; the delay device based on the optical chip delays microwave signals of different frequencies modulated on the optical carrier. It overcomes the problem of beam deflection; the gain of all components can be controlled independently, and the Gaussian distribution of the gain of the array element can be realized, so as to achieve beam scanning with high sidelobe suppression ratio.

Description

Light-controlled microwave phased array radar system based on pluggable receiving and transmitting assembly and feedback control method

Technical Field

The invention relates to a microwave phased array radar technology, in particular to a pluggable transceiver-based light-operated phased array radar system and a control method thereof.

Background

With the rapid development of information technology, the future war will develop towards large-depth and three-dimensional operation, and with the leap-type promotion of satellite communication technology and artificial intelligence technology, the whole operation will develop towards sea, land, air and space integration, intellectualization and multi-platform fusion. The system has the characteristics of ultra-long distance, all-weather, rapidness, flexibility and accuracy, and a highly developed information acquisition, control and use technology occupies an increasingly important position in future war. As a radar transmitting and receiving system plays a role in "fright" and "leeward" in war, it will play a crucial role in this process. Therefore, broadband receiving and processing of radar signals and ubiquitous sensing and access of information are hot and difficult problems in current radar research.

The fiber-optic communication technology as backbone and core in the communication field has proved its superior broadband data processing capability in decades of development. Meanwhile, the traditional microwave technology shows a certain capability in ubiquitous sensing and access. Compared with the traditional microwave technology, the optical communication has the capabilities of ultralow loss (<0.1dB/km) and electromagnetic interference resistance, and the two technologies are fused, so that the microwave photon technology is born. The American navy laboratory is subject to 'photonics illuminates the future of the radar', and the technology is promoted to a very important height in the engineering application of the radar. At present, the research results of the microwave photon radar technology at home and abroad show that compared with the traditional microwave signal processing technology, the microwave photon technology has ultra-large bandwidth and strong flexibility, and the performance of the whole radar system is improved. However, most microwave photonic radar systems are currently built on discrete optical devices or equipment. The development of the microelectronics industry is pointing towards the development of microwave photonics. Along with the rapid development of integrated optics, the integrated microwave photon technology developed based on a multi-material platform lays a solid foundation for the miniaturization and the generalization of the microwave photon radar.

However, most integrated microwave photonic chips are currently implemented on a single material platform, which can only implement some single functions, and the system size cannot be further reduced. Meanwhile, most radars use a single antenna structure, not an antenna structure based on a phased array. Compared with the traditional single antenna or circular antenna radar, the phased array radar has the advantages of high stability, strong flexibility, long detection distance and the like, and the principle is that the direction of a wave beam can be changed to scan by using the electromagnetic wave coherence principle and controlling the phase of current fed to each radiating element through a computer, as shown in figure 1. Conventional phased array radars based on electrical transposers produce beam-skewing phenomena that can be solved using photon-based true delay lines by merely changing the time difference between the antenna elements, as shown in fig. 1. The multi-material mixed heterogeneous integrated microwave photon technology assembles the advantages of multiple platforms, and provides important support for the fully integrated, multifunctional, miniaturized and practical development of the microwave photon phased array radar. At present, the scheme of using heterogeneous integration technology or multi-material platform fusion technology is rarely reported.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a light-operated phased array radar system and a control method based on a pluggable receiving and transmitting component. The technical scheme adopted by the invention is that photonic integrated chips with different functions are realized by using multiple material platforms, multiple chips are interconnected through an advanced coupling technology among optical chips to realize a receiving and transmitting assembly of all-optical integration, and meanwhile, a flip-chip or wire-bonding technology is used for encapsulating a control electric chip and the optical chip assembly in the same tube shell, so that the pluggable receiving and transmitting assembly and the light-controlled phased array radar system formed by the pluggable receiving and transmitting assembly are finally obtained.

The technical scheme of the invention is as follows:

the invention firstly provides a light-controlled phased array radar system based on a pluggable receiving and transmitting component, wherein each antenna array element of the light-controlled phased array radar system is provided with the pluggable receiving and transmitting component; each pluggable receiving and transmitting component can generate and receive electromagnetic waves, so that each antenna array element can be independently controlled, and beams with different directions and transmitting powers can be synthesized by controlling the optical delay and gain of the corresponding receiving and transmitting component of each antenna array element;

the pluggable receiving and dispatching assembly is based on the pluggable receiving and dispatching assembly of the all-optical integrated chip, and comprises: the system comprises a transmitting end, a receiving end, an MCU, an RF Driver, a band-pass filter and an FPGA or DSP; the transmitting end and the receiving end are both composed of a signal electrode and an optical chip, and the signal electrode and the optical chip are electrically interconnected;

the MCU comprises a signal generator, the MCU is used for controlling an RF Driver and an FPGA or a DSP and communicating with a master control module of the light-controlled phased array radar system, and the FPGA or the DSP is used for feedback control of light chips in a transmitting end and a receiving end; the RF driver is used for amplifying the electric signal, and the band-pass filter filters the electric signal amplified by the RF driver and transmits the electric signal to the optical chips in the transmitting end and the receiving end.

The master control module of the light-controlled phased array radar system is used for providing needed parameters such as radar transmitting gain, receiving sensitivity, beam pointing angle and the like for the MCU in the receiving and transmitting assembly, so that system indexes are decomposed into each receiving and transmitting assembly, and control over devices on an optical chip of the receiving and transmitting assembly corresponding to each antenna array element is achieved.

As a preferred scheme of the present invention, the transmitting end optical chip includes a laser, a retarder and a photodetector, the MCU generates an electrical signal corresponding to an index according to requirements of the photo-controlled phased array radar system, the electrical signal is amplified by the RF driver and filtered by the BPF, the laser or the modulator on the optical chip is modulated, the modulated optical signal is delayed by the retarder, the photodetector converts the delayed optical signal into an electrical signal, and the electrical signal is transmitted to a corresponding antenna element by the signal electrode and finally transmitted by the corresponding antenna element.

As a preferred scheme of the present invention, the receiving end optical chip includes a laser, a retarder and a photodetector; according to the requirements of the phased array radar reconnaissance angle and range, the MCU transmits an instruction to the FPGA or the DSP, and the PFGA or the DSP controls a delayer on the optical chip to obtain corresponding delay and gain; an electric signal received from an antenna is accessed into an RF driver through a signal electrode of a receiving end to be amplified, a laser or a modulator on an optical chip is modulated through BPF filtering, the modulated optical signal is delayed through a delayer, then the delayed optical signal is converted into the electric signal through a photoelectric detector, the electric signal is subjected to signal processing in an FPGA/DSP, and the obtained parameter performance is fed back to a master control module of the light-controlled phased array radar system through an MCU.

As a preferable scheme of the invention, if the frequency band of the phased array radar is lower than 10GHz and the requirement of the dynamic range of the system is lower than 100dB, an electric signal direct modulation laser scheme can be used. Thus, the complexity and the cost of the system can be reduced; if the working frequency band of the system is more than 10GHz, the linearity requirement of the link is more than 110dB Hz^2/3Then a highly linear external modulator is needed to achieve the photoelectric conversion. Such as a high linearity SOI-MZM or a SOI-LiNbO3 MZM, in which case the laser is used only as a light source and not as a photoelectric conversion device. In both schemes, the BPF is only used to filter out the out-of-band noise of the desired electrical signal, resulting in a desired electrical signal of high purity.

As a preferred scheme of the present invention, the retarder in the optical chip is a binary integrated optical delay line biudl, and the binary integrated optical delay line biudl includes 1 polarization rotator PR, an N-stage 2 × 2 port delay subunit TDSU, and a 1-stage 2 × 2 mach-zehnder interferometer structured optical switch MZI-OS, which are sequentially connected; an upper output path of the Mach 2 Mach-Zehnder interferometer structured optical switch MZI-OS is sequentially connected with a 1-level semiconductor optical amplifier SOA, a 1-level continuous adjustable delay unit and a GePD, and a lower output path of the Mach 2 Mach-Zehnder interferometer structured optical switch MZI-OS is connected with the GePD; the GePD is used to demodulate the optical signal to be output into an electrical signal.

As a preferable scheme of the invention, the MZI-OS is based on the carrier dispersion effect or the thermo-optic effect of a silicon material; and controlling the MZI-OS state through the output voltage of the FPGA or the DSP.

As a preferred scheme of the invention, the TDSU comprises 1 MZI-OS, and the upper and lower paths of the MZI-OS are respectively provided with 1 variable optical attenuator VOA and 1 direct coupler DC with 1 multiplied by 2 ports; two ports of the upper direct coupler DC are respectively connected with the SOI-GePD and the delay waveguide, and two ports of the lower direct coupler DC are respectively connected with the SOI-GePD and the reference waveguide; the direct coupler DC is used for monitoring the working state of the MZI-OS; the two-port splitting ratio of the direct coupler DC can be set to an arbitrary ratio.

The invention also provides a feedback control method of the light-operated phased array radar system, which comprises the following steps:

A. gain control

When the laser is directly modulated by using an electric signal, the VOA on the optical chip is controlled to adjust the link loss corresponding to each antenna array element, so that the gain control of the whole radar system is realized;

when an external modulator SOI-MZM/SOI-LiNbO is modulated by using an electric signal₃When in MZM, the control of the link gain of the corresponding antenna array element is realized by controlling the output power of the laser and/or the amplification factor of the InP-SOA, so that the gain control of the whole phased array radar system can be realized;

B. pointing angle control

The delay control of the corresponding single antenna array element is realized by controlling the delay state switching on the optical chip, and the pointing angle control of the synthesized beam is realized by controlling the delayers on the optical chip in the transceiving components corresponding to all the antenna array elements of the whole phased array radar system;

specifically, the discrete delay state realizes real-time feedback control by controlling the driving voltage of the MZI-OS and monitoring the magnitude of GePD output optical current on a corresponding path; the continuous delay is regulated and controlled by modulating two single-tone low-frequency small signals onto a laser or a modulator, monitoring the phase difference between the two single-tone signals, reflecting the continuous delay, feeding back to a DSP or an FPGA, adjusting the effective refractive index of a CTDU, and realizing the feedback control of the continuous delay.

For single array element delay feedback control, because the pointing angle of the phased array radar is determined by the delay on the corresponding transceiving component of each antenna array element, accurate feedback control delay is necessary. For the feedback control of the discrete delay, the switch switching of the corresponding path is mainly used, and the state monitoring of the switch mainly depends on the magnitude of the photocurrent of the GePD on the corresponding path, so that the GePD current is monitored while the drive voltage is applied to the switch until the photocurrent on the corresponding path reaches the maximum, namely the discrete delay state is subjected to real-time feedback control; the continuous delay regulation is mainly used for compensating delay errors caused by discrete delay, two low-frequency small signals are added to the transmitting signal and the receiving signal, the phase difference of the small signals is monitored, the change of the continuous delay can be observed, and the driving voltage on a continuous delay device is regulated until the discrete errors are completely compensated.

For single-element gain control, the beam sidelobe suppression ratio of the phased array radar mainly depends on the magnitude of the transmitted power on each antenna, so that the adjustment and control of the gain on each antenna element are very important. The magnitude of the gain in the transceiving component is observed by monitoring the magnitude of the photocurrent of the E1 terminal of the delayer on each transceiving component. And the gain of each antenna array element is controlled by adjusting and controlling the driving voltage of the VOA or the InP-SOA on the optical chip.

Compared with the prior art, the invention has the following beneficial effects:

(1) because the microwave phased array radar component is constructed based on the optical chip, compared with the traditional electric chip framework, the microwave phased array radar component has strong electromagnetic interference resistance; in the conventional electric phased array radar, because a high-frequency signal is transmitted on a metal transmission line, a skin effect exists, the transmission loss of the signal is increased, and the problems do not exist when an optical chip is adopted to transmit the signal. Meanwhile, the optical transmission bandwidth is hundreds of times of the electrical bandwidth, so that the signal transmission capacity is improved;

(2) compared with the traditional electric phase shifter, the optical chip-based delayer has the same delay for microwave signals with different frequencies modulated on optical carriers, so that the beam deflection problem is solved; moreover, the traditional electric positioner has large volume and large power consumption, and the optical chip can push the whole phased array radar to be miniaturized;

(3) compared with the existing microwave phased array radar system based on the optical chip architecture, a large part of the existing microwave phased array radar system is a single light source or a coherent mode, and the mode reduces the reliability of the system. The light-controlled microwave phased array radar is formed on the basis of light receiving and transmitting components, each component is provided with an independent light source, a delayer and the like, and the reliability and the stability of a system are greatly improved. And the gains of all the components can be controlled independently, and the Gaussian distribution of the array element gains can be realized, so that the beam scanning with high sidelobe suppression ratio is realized.

Drawings

Fig. 1 is a schematic diagram of the operation of a phased array radar.

Fig. 2 is a schematic structural diagram of a transceiver module according to the present invention.

Fig. 3 is a schematic diagram of the structure of the biedl.

FIG. 4 is a schematic diagram of MZI-OS.

Fig. 5 is a schematic diagram of phased array radar beam pointing versus operating frequency. Wherein, the left side is the electric phased array radar with beam deflection; the right side is the light-operated phased array radar of the invention without beam deflection.

Fig. 6 is a schematic diagram of a scheme 1 transceiver module.

Fig. 7 is a schematic diagram of a scheme 2 transceiver module.

Fig. 8 is a schematic diagram of an embodiment 3 transceiver module.

Fig. 9 is a schematic diagram of an overall phased array framework.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 9 is a schematic diagram of an optically controlled phased array radar system based on a pluggable transceiver module according to the present invention. Each antenna array element of the light-operated phased array radar system is provided with a pluggable receiving and transmitting component; each pluggable receiving and transmitting component can generate and receive electromagnetic waves, so that each antenna array element can be independently controlled, and beams with different directions and transmitting powers can be synthesized by controlling the optical delay and gain of the corresponding receiving and transmitting component of each antenna array element;

As shown in fig. 2, the pluggable transceiver module includes: the transceiver comprises a transceiver optical chip, an electric signal interface (signal electrode) with an antenna array, a Micro Control Unit (MCU), a programmable gate array (FPGA) or a Digital Signal Processor (DSP), a radio frequency signal driver (RF driver) and an electric Band Pass Filter (BPF). The signal electrodes are used to interconnect with corresponding electrical interfaces on the antenna, and the three electrodes are only used for illustration and do not represent that only three electrodes exist in the actual design. The micro control unit MCU is used for communicating with a peripheral control module (FPGA/DSP/RF driver) and a system master control module, and meanwhile, the MCU comprises a signal generator. The FPGA/DSP is used for performing feedback control on corresponding devices on the optical chip (such as bias on working points of the modulator, state control on the delay device and the like). The RF driver is used for amplifying the electric signal, then the electric signal is converted to an optical domain through a modulator on the optical chip after being filtered by the band-pass filter BPF, so that the time delay and gain weighting of the signal can be carried out on the optical chip, and the control of the transmitting and receiving wave beams of the phased array radar is realized.

The transmitting terminal comprises a signal electrode and an optical chip, wherein the optical chip comprises a laser, a delayer and a photoelectric detector. And according to the requirement of the phased array radar system, the MCU generates an electric signal corresponding to the index. The electric signal is amplified by an RF driver and filtered by a BPF to modulate a light source or a modulator on an optical chip, the modulated optical signal is delayed by a delayer, then the delayed optical signal is converted into the electric signal by a photoelectric detector, the electric signal is transmitted to a corresponding antenna array element by a signal electrode, and finally the electric signal is transmitted by the corresponding antenna array element.

The receiving end comprises a signal electrode and an optical chip, wherein the optical chip comprises a laser, a delayer and a photoelectric detector. According to the requirements of the phased array radar reconnaissance angle and range, the MCU transmits a corresponding instruction to the FPGA/DSP, and the PFGA/DSP controls a delayer on the optical chip to obtain corresponding delay and gain. The electric signal received from the antenna is accessed to the RF driver through a signal electrode of a receiving end for amplification, a light source or a modulator on the optical chip is modulated through BPF filtering, the modulated optical signal is delayed through a delayer, then the delayed optical signal is converted into the electric signal through a photoelectric detector, the electric signal is subjected to signal processing in the DSP, and the obtained parameter performance is fed back to the peripheral main control board through the MCU.

In an embodiment of the present invention, the optical chip includes a distributed Feedback laser dfbl (distributed Feedback laser) or a Mach-Zehnder modulator MZM (Mach-Zehnder modulator), a retarder, and a photodetector. The DFBL is designed and manufactured based on indium phosphide (InP) material platform. The MZM is a silicon-on-insulator (SOI-MZM) or a silicon-based lithium niobate thin film MZM (SOI-LiNbO) based on silicon-on-insulator (SIO-on-insulator) carrier dispersion effect₃MZM). The photoelectric detector is a silicon-based germanium photoelectric detector SOI-GePD (Ge photodiode). In addition to InP-DFBL, SOI-MZM/SOI-LiNbO₃The MZM, the delay, and the SOI-GePD may be fabricated on the same chip using an SOI processing platform.

The InP-DFBL couples the optical signal generated by the laser into the SOI optical chip by flip chip bonding or multi-stage micro-lens, and the optical chip comprises a modulator, a delayer and a photoelectric detector.

In an embodiment of the present invention, the retarder is a binary integrated optical delay line (binary integrated optical Time delay line), and as shown in fig. 3, the retarder includes 1 polarization rotator pr (polarization rotator), a N-stage 2 × 2 port delay subunit TDSU (Time delay sub-unit), a 1-stage 2 × 2 Mach 2 interferometer structured light switch MZI-OS (Mach-Zehnder optical switch), a 1-stage semiconductor optical amplifier (soa semiconductor optical amplifier), a 1-stage continuously adjustable delay unit (Continuous delay unit), and two last ports each having an SOI-GePD. The connection of the devices is shown in fig. 3.

The MZI-OS is based on the carrier dispersion effect or the thermo-optic effect of silicon material. As shown in FIG. 4, the 2X 2MZI-OS has 4 optical ports, with O1 and O2 as input ports and O3 and O4 as output ports. Assuming that the input port is O1, the phase shift arm is voltage-controlled to change the phase difference of the upper and lower arms, so that an optical signal can be output from O3 or O4. If the optical signal is output from only O3, it is in the bar state, if the optical signal is output from only O4, it is in the cross state, and if there are outputs from both ports, it is in the intermediate state. Therefore, the control of the MZI-OS state can be realized through the FPGA/DSP output voltage.

The SOA is an InP-based material platform and is bonded at the corresponding position of the SOI optical chip in a flip chip bonding mode. The PR converts optical signals with different polarization states into the same polarization state.

In an embodiment of the present invention, the TDSU is shown in fig. 3, and includes 1 MZI-OS, 1 variable optical attenuator voa (variable optical attenuator) in the upstream and downstream, and 1 direct coupler dc (direct coupler) with 1 × 2 ports. Two ports of the DC are respectively connected with the SOI-GePD and the delay (delay)/reference (ref) waveguide. The DC is used to monitor the operating state of the MZI-OS. The two-port splitting ratio of the DC can be set to any ratio, typically 5% to 95%, i.e., 5% of the optical power is input to the SOI-GePD and 95% of the optical power is input to the delay (delay)/reference (ref) waveguide.

Suppose that the 1 st order TDSU delay waveguide length is L_D1Reference waveguide length L_R1The group refractive index of the waveguide is n_gAnd c is the speed of light, the delay time of the N-th stage TDSU is delta tau_N＝n_g2^N-1(L_D1-L_R1) And c, the ratio of the total weight to the total weight of the product. The number of discrete delay states of the entire BIOTDL is then 2^N-1。

The VOA is a carrier injection type PIN junction optical waveguide or MZI structure interferometer and is used for improving the extinction ratio of the MZI-OS and regulating and controlling the link gain.

Because the TDSU is discrete delay, which causes discontinuity of the final radar scan angle, CTDU needs to be added. In the present invention, CTDUs are realized by heating or otherwise changing the effective refractive index of a long length of waveguide (typically 5 cm).

The mentioned biedl add path is an output path, so that a GePD is connected to the last add path to demodulate the optical signal to be output into an electrical signal, and output from the electrical output port E1. Since the terminals E1 and E2 are complementary outputs, E2 is set as the state monitor terminal of the last stage MZI-OS.

As shown in fig. 6-8, schematic diagrams of three specific designs of optical chips in pluggable transceiver module based on all-optical integrated chip are shown for the embodiments. Since the control and driving circuit parts are the same, and the optical chips at the transmitting and receiving ends have the same structure, the difference is the structure of the optical chip, and here we only discuss the structural design of the optical chip.

Fig. 6 is a schematic structural diagram (which can be regarded as a top view) of an optical chip in scheme 1, where the optical chip mainly includes an InP-DFB laser chip and an SOI-biadl chip, and the optical chips of these two materials are coupled together by a multi-stage lens, a flip-chip bonding structure, and the like. The main role of the InP-DFB chip is to modulate the electrical signals that need to be transmitted or received by the antenna into the optical domain. The SOI-BIOTDL has the functions of delaying the electric signal in the optical domain and demodulating the optical signal into the electric signal;

specifically, at the transmitting end, the MCU generates a required electrical signal to drive the RF driver so that the electrical signal is amplified, BPF filters the electrical signal and modulates the InP-DFB, and the modulated optical signal is coupled into the optical input port of the SOI-biadl via a multi-stage lens or a flip chip bonding structure. The optical signal passes through a time delay in the BIOTDL, is finally demodulated into an electric signal by GePD and is transmitted through a connected antenna. The delay state (namely delay amount) of the BIOTDL is controlled by a switch on an FPGA/DSP driving optical chip, and the delay size is determined by the beam pointing angle required by the phased array radar system. The angle information is sent by the system master control board and transmitted to the MCU, the MCU converts the angle information into switch state information and driving voltage information of the CTDU, the FPGA/DSP generates different driving voltage signals according to the information and applies the driving voltage signals to corresponding electrodes, and therefore time delay control of the BIOTDL is achieved. The gain of the electric signal of the transmitting end is controlled by the VOA on the FPGA/DSP driving optical chip, the gain is determined by the transmitting power of the phased array radar, and the specific control mode is similar to the delay control.

Specifically, at the receiving end, unlike the transmitting end, the electrical signal is received by the antenna, rather than being generated by the MCU. And the electric signal after GePD demodulation is sampled by FPGA/DSP and processed to obtain information such as frequency power of the signal.

Fig. 7 is a schematic diagram of a photonic chip structure in scheme 2, comparing with scheme 1, a silicon-based MZM carrier depletion modulator is used. The optical signal generated by the InP-DFB laser is modulated to the optical domain via the SOI-MZM, with other steps as above, having higher linearity or dynamic range compared to the DFB direct modulation laser scheme.

Fig. 8 is a schematic diagram of an optical chip structure in scheme 3, which uses carrier dispersion effect compared to the SOI-MZM in scheme 2, and although high linearity can be achieved by changing reverse bias voltage, the complexity is high. The lithium niobate crystal has a first-order electro-optic effect, and the linearity of the whole link can be greatly improved by heterointegration of the LiNbO3 thin film MZM. The other steps are the same as above.

In one embodiment of the present invention, a phased array with an array size of 18 × 18 is taken as an example, as shown in fig. 9, where d is the antenna array element spacing (assuming that the center frequency is f, the light speed is c, and d ≦ c/2f according to the half-wavelength limitation), so that the cross-sectional area of the whole size of the packaged transceiving module is ≦ d × d.

The feedback control method of the light-operated phased array radar system comprises gain control and pointing angle control, the pointing angle of the phased array radar is determined by the time delay on the transceiving component corresponding to each antenna array element, and the beam sidelobe suppression ratio of the phased array radar is mainly determined by the size of the transmitting power on each antenna.

A. Gain control

in particular, the method comprises the following steps of,

when the laser is directly modulated by using an electric signal, the gain of the electric signal is regulated and controlled by regulating the VOA driving voltage, the magnitude of the gain is fed back to the MCU through the output light current of the upper output path E1 port, the MCU is communicated with the radar master control board to obtain the electric signal gain required to be set by the pluggable receiving and transmitting component, and the MCU regulates and controls the corresponding pluggable receiving and transmitting component after obtaining an instruction until the electric signal gain reaches a set value;

when using electric signal to modulate SOI-MZM/SOI-LiNbO₃During MZM, the gain of an electric signal is regulated and controlled by regulating the optical power output by a laser, the driving voltage of VOA and the driving voltage of InP-SOA, the magnitude of the gain is fed back to an MCU in the pluggable receiving and transmitting assembly through an upper output path E1 port, the MCU is communicated with a radar master control board to obtain the electric signal gain required to be set by the pluggable receiving and transmitting assembly, and the MCU regulates and controls the corresponding pluggable receiving and transmitting assembly after obtaining an instruction until the electric signal gain reaches a set value.

B. Pointing angle control

The phase of the traditional electric phase shifter is a constant in a frequency band, so that the delay of different signals in the frequency band is different, thereby causing beam deflection, namely, the spatial orientation of electric signals with different frequencies (here, we exemplify frequencies of 7GHz, 8GHz and 9GHz) is different after passing through a beam forming network formed by the electric phase shifter. For the time shifter based on the optical chip, the time delay of all frequency signals of the frequency band is the same, so that the beam deflection problem does not occur. Meanwhile, the spatial direction of the wave beam is realized by controlling the relative delay of the delayers in the adjacent components. As shown in fig. 5.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. an optically controlled phased array radar system based on a pluggable transceiver assembly, wherein each antenna array element of the optically controlled phased array radar system has a pluggable transceiver assembly; Each pluggable transceiver component can generate and receive electromagnetic waves, so that each antenna element can be independently controlled. By controlling the optical delay and gain of each antenna element corresponding to the transceiver component, beams with different directions and transmit power can be synthesized;

The pluggable transceiver component is a pluggable transceiver component based on an all-optical integrated chip. The pluggable transceiver component includes: a transmitter, a receiver, an MCU, an RF Driver, a band-pass filter, and an FPGA or DSP ; The transmitting end and the receiving end are composed of signal electrodes and optical chips, and the signal electrodes and the optical chips are electrically interconnected;

The MCU includes a signal generator, the MCU is used to control the RF Driver and the FPGA or DSP, and communicates with the general control module of the optically controlled phased array radar system, and the FPGA or DSP is used to feedback control the optical chip inside the transmitter and the receiver; The RF driver is used to amplify the electrical signal, and the band-pass filter filters the electrical signal amplified by the RF driver and transmits it to the optical chip in the transmitter and receiver.

2. The optically controlled phased array radar system based on a pluggable transceiver assembly according to claim 1, wherein the transmitting end optical chip comprises a laser, a delay device and a photodetector, according to the optical control According to the requirements of the phased array radar system, the MCU generates an electrical signal corresponding to the index. After the electrical signal is amplified by the RF driver and filtered by the BPF, the laser or modulator on the optical chip is modulated, and the modulated optical signal passes through the delay device. Delay, then the photodetector converts the delayed optical signal into an electrical signal, the electrical signal is conducted by the signal electrode to the corresponding antenna element, and finally emitted by the corresponding antenna element.

3. The optically controlled phased array radar system based on a pluggable transceiver assembly according to claim 1, wherein the receiving end optical chip comprises a laser, a delay device and a photodetector; According to the requirements of the reconnaissance angle and range of the radar array, the MCU transmits instructions to the FPGA or DSP, and the FPGA or DSP controls the delay device on the optical chip to obtain the corresponding delay and gain; the electrical signal received from the antenna is connected through the signal electrode at the receiving end After being amplified by the RF driver, the laser or modulator on the optical chip is modulated by BPF filtering, the modulated optical signal is delayed by the delay device, and then the delayed optical signal is converted into an electrical signal by the photodetector. The electrical signal is processed in FPGA/DSP, and the obtained parameter performance is fed back to the general control module of the optical phased array radar system by the MCU.

4. the optically controlled phased array radar system based on the pluggable transceiver assembly according to claim 2 or 3, is characterized in that, the delay device in the described optical chip is a binary integrated optical delay line BIOTDL, The binary integrated optical delay line BIOTDL includes a polarization rotator PR, an N-stage 2×2 port delay subunit TDSU, and a 1-stage 2×2 Mach-Zehnder interferometer structured optical switch MZI-OS connected in sequence; The upper output path E1 of the 2×2 Mach-Zehnder interferometer structured optical switch MZI-OS is sequentially connected to a 1-stage semiconductor optical amplifier SOA, a 1-stage continuously adjustable delay unit and a GePD, and the 2×2 Mach-Zehnder interferometer structure The lower output path E2 of the optical switch MZI-OS is connected to a GePD; the GePD is used to demodulate the optical signal to be output into an electrical signal.

5. The optically controlled phased array radar system based on pluggable transceiver components according to claim 4, wherein the MZI-OS is based on the carrier dispersion effect or the thermo-optic effect of silicon materials; The FPGA or DSP output voltage controls the MZI-OS state.

6. The optically controlled phased array radar system based on a pluggable transceiver assembly according to claim 4, wherein the TDSU comprises 1 MZI-OS, and the upper and lower paths of the MZI-OS have 1 MZI-OS respectively. A variable optical attenuator VOA and a 1×2-port direct coupler DC; the two ports of the upper direct coupler DC are respectively connected to SOI-GePD and the delay waveguide, and the two ports of the lower direct coupler DC are respectively connected to SOI -GePD and reference waveguide; the direct coupler DC is used to monitor the working state of the MZI-OS; the splitting ratio of the two ports of the direct coupler DC can be set to any ratio.

7. a feedback control method of the described optical control phased array radar system of claim 4, is characterized in that:

A. Gain control

When using an electrical signal to directly modulate the laser, the link loss corresponding to each antenna element is adjusted by controlling the VOA on the optical chip, thereby realizing the gain control of the entire radar system;

When using the electrical signal to modulate the external modulator SOI-MZM/SOI-LiNbO ₃ MZM, the link gain of the corresponding antenna element can be adjusted by adjusting the output power of the laser and/or the InP-SOA amplification factor, so that the entire phase can be adjusted. Gain control of array radar system;

B, pointing angle control

By controlling the delay state switching on the optical chip, the delay control of the corresponding single antenna array element is realized, and the delay device on the optical chip in the transceiver components corresponding to all the antenna array elements of the entire phased array radar system is controlled at the same time. , to realize the pointing angle control of the synthetic beam;

Specifically, the discrete delay state realizes real-time feedback control by controlling the driving voltage of the MZI-OS and monitoring the size of the GePD output photocurrent on the corresponding path; the continuous delay control uses two single-tone low-frequency small signals to be modulated to the laser or On the modulator, monitoring the phase difference between the two single-tone signals can reflect the size of the continuous delay, and then feed it back to the DSP or FPGA to adjust the effective refractive index of the CTDU to realize the feedback control of the continuous delay.

8. The feedback control method of optical control phased array radar system according to claim 7, is characterized in that, it is characterized in that described gain control is specifically:

When using the electrical signal to directly modulate the laser, the gain of the electrical signal is regulated by adjusting the VOA driving voltage. The gain is fed back to the MCU through the output photocurrent of the E1 port of the upper output path. For the electrical signal gain that needs to be set for the pluggable transceiver component, the MCU controls the corresponding pluggable transceiver component after getting the command until it reaches the set value;

When using electrical signals to modulate SOI-MZM/SOI-LiNbO ₃ MZM, the gain of the electrical signal is regulated by adjusting the optical power output by the laser, the driving voltage of VOA and the driving voltage of InP-SOA, and the gain is determined by the upper output path E1 The output photocurrent size of the port is fed back to the MCU in the pluggable transceiver component. The MCU communicates with the radar main control board to obtain the electrical signal gain that the pluggable transceiver component needs to set. After the MCU gets the command, it regulates the corresponding pluggable and pluggable components. type transceiver components until the set value is reached.