CN116054956A - Diversity receiving system suitable for coherent laser communication - Google Patents
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Abstract
The invention relates to the technical field of space laser communication, and discloses a diversity receiving system suitable for coherent laser communication, which comprises a main branch, N branch circuits and a coherent combining module, wherein the main branch circuits, the N branch circuits and the coherent combining module are arranged side by side, the N branch circuits are sequentially increased according to the serial numbers from the main branch circuit from the near to the far, and the serial numbers are respectively recorded as 1,2, i, N; the main branch comprises an optical amplifier, a 90-degree optical mixer and a homodyne coherent optical receiver which are sequentially connected, each branch comprises the optical amplifier and the 90-degree optical mixer which are sequentially connected, each 90-degree optical mixer is provided with one path of optical signal input, the output end of each branch and the output end of each phase noise compensation module are respectively connected with the input end of the coherent combining module, and the output end of the homodyne coherent optical receiver is also respectively connected with the input end of each 90-degree optical mixer. The invention solves the problems of higher implementation complexity and the like in the prior art.
Description
Technical Field
The invention relates to the technical field of space laser communication, in particular to a diversity receiving system suitable for coherent laser communication.
Background
The space laser communication has the advantages of high communication speed, large information capacity, strong anti-interference capability, high confidentiality and the like, and is gradually applied to the aspects of satellite communication, laser radio frequency integrated communication, emergency communication, tactical communication, 5G backhaul and the like. When the laser signal is transmitted in an atmosphere channel, the laser signal is influenced by the effects of atmosphere scattering, atmosphere absorption, atmosphere turbulence, cloud mist and the like, so that the received optical signal generates random fading and attenuation, and the link reliability of laser communication is reduced. Because of the uncorrelation of different paths of the atmosphere channel, diversity reception is performed by adopting a plurality of receiving antennas at the receiving end, so that the influence of the atmosphere channel can be effectively restrained, and the reliability of laser communication is improved. The diversity receiving structure based on single-shot multi-receiver has been widely studied in space laser communication because of its simple structure and the capability of referencing the signal combining algorithm of traditional wireless communication.
In practical laser communication system design, especially coherent laser communication, a receiver often faces technical challenges such as large frequency difference (in GHz order) between signal light and local oscillator light, difficulty in synchronizing multiple optical signals, and the like, so that the practical application of diversity reception on a laser communication system is limited. In the prior art [1] (Michael G.Taylor.Phase Estimation Methods for Optical Coherent Detection Using Digital Signal processing.journal of Lightwave Technology,2009,27 (7)) a digital signal processing algorithm is adopted to perform phase noise compensation, but for the problem of large frequency difference of GHz, the algorithm compensation has the difficulties of large power consumption, large resource consumption, large time delay and the like. The prior art [2] (Zhou Zunzhen, zhou Haijun, xie Weilin, qin Jie, dong Yi.10-Gb/shomodyne receiver based on Costas loop with enhanced dynamic performance.IEEE International Conference on Optical Communications and Networks (ICOCN), 2017.) proposes a homodyne coherent receiver based on an optical phase lock technique, which can compensate a larger frequency difference between signal light and local oscillation light in real time, but does not consider how to apply the receiver to a diversity receiving system. In the prior art [3] (analog belmonte. Digital equalization of time-delay array receivers on coherent laser communications. Optics Letters,2017,42 (2)), an optical fiber phase shifter and an optical fiber delay line are adopted to synchronously receive multiple optical signals, and although diversity reception of coherent laser communication is realized, complicated phase stabilization, vibration isolation and other controls need to be performed on the optical fiber phase shifter, the optical fiber delay line and the like due to random jitter and drift of the optical signals of each branch, so that the implementation complexity is higher.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a diversity receiving system suitable for coherent laser communication, which solves the problems of higher implementation complexity and the like in the prior art.
The invention solves the problems by adopting the following technical scheme:
a diversity receiving system suitable for coherent laser communication comprises a main branch, N branch circuits and a coherent combining module, wherein the main branch circuits, the N branch circuits and the coherent combining module are arranged side by side, the N branch circuits are sequentially increased according to the numbers of the directions from the near to the far of the main branch circuits, and the numbers are respectively recorded as 1,2, i, N; the main branch comprises an optical amplifier, a 90-degree optical mixer and a homodyne coherent optical receiver which are sequentially connected, each branch comprises the optical amplifier and the 90-degree optical mixer which are sequentially connected, each 90-degree optical mixer is provided with one path of optical signal input, the output end of each branch and the output end of each phase noise compensation module are respectively connected with the input end of the coherent combining module, and the output end of the homodyne coherent optical receiver is also respectively connected with the input end of each 90-degree optical mixer; wherein i represents the number of the branch, i is more than 1 and less than or equal to N, N is more than or equal to 2, and i and N are integers.
As a preferred technical scheme, each branch further comprises a balance detector, and in each branch, the optical amplifier, the 90-degree optical mixer and the balance detector are connected in sequence.
As a preferable technical scheme, each branch circuit further comprises a phase noise compensation module, and in each branch circuit, the optical amplifier, the 90-degree optical mixer, the balance detector and the phase noise compensation module are connected in sequence.
As a preferable technical scheme, the phase noise compensation module comprises a low-pass filtering module, an analog-to-digital conversion module, a phase recovery algorithm module and a signal judgment module which are sequentially connected, wherein the output end of the signal judgment module is connected with the input end of the coherent combining module.
As a preferable technical scheme, the coherent combining module comprises K coherent branches and an adder, each coherent branch comprises a channel estimation module and a matched filtering module which are connected with each other, and the output end of each matched filtering module is respectively connected with the input end of the adder; wherein K is more than or equal to 2 and K is an integer.
As a preferred technical scheme, the coherent combining module further comprises a phase synchronization module, wherein the input end of the phase synchronization module is respectively connected with the output end of each matched filtering module, and the output end of the phase synchronization module is connected with the input end of the adder.
As a preferred technical scheme, the coherent combining module further comprises a time delay synchronization module, wherein the input end of the time delay synchronization module is connected with the output end of the phase synchronization module, and the output end of the time delay synchronization module is connected with the input end of the adder.
As a preferred technical solution, the signal modulation format of the homodyne coherent optical receiver is BPSK, and the modulation format is transparent.
As a preferred embodiment, n=2.
As a preferable technical scheme, the center wavelength of the local oscillation laser output by the homodyne coherent optical receiver is 1550nm, and the tuning range reaches 40GHz.
Compared with the prior art, the invention has the following beneficial effects:
(1) The invention can be directly applied to spatial coherent laser communication, atmospheric laser communication and the like, and greatly reduces the system error rate of laser communication, thereby improving the link reliability of laser communication;
(2) In the invention, the homodyne coherent receiver of the main branch circuit uses an optical phase locking technology to compensate larger frequency difference between signal light and local oscillation light, and outputs the local oscillation light to be supplied to other branch circuits for coherent detection, thereby avoiding the repeated use of complex optical phase locking technology by other branch circuits;
(3) In the invention, the local oscillation light and the signal light of the branch have no frequency difference and only have residual phase deviation, thereby avoiding the troublesome problems of simultaneously compensating larger frequency difference, random phase deviation and the like in digital coherent reception, and demodulating the digital signal by a simple phase noise compensation algorithm, and having low design difficulty and low power consumption;
(4) In the invention, the coherent combining module adopts the technologies of channel estimation, phase synchronization, time delay synchronization and the like to realize the coherent combining of multiple paths of signals, and has strong environmental adaptability and low implementation complexity;
(5) The invention can realize diversity reception under different atmosphere channel conditions by flexibly adjusting the pilot frequency quantity of the data frame;
(6) The invention adopts transparent modulation format, compatible with homodyne coherent reception and diversity reception of high-order modulation formats such as on-off keying (OOK), binary phase keying modulation (BPSK), differential Phase Shift Keying (DPSK), quaternary Quadrature Phase Shift Keying (QPSK), quadrature Amplitude Modulation (QAM) and the like;
(7) The invention belongs to mixed homodyne (analog) coherent receiving and digital coherent receiving technology, uses mature commercial devices, has simple combination mode and is easy to popularize to diversity receiving of multiple paths (N > 3).
Drawings
Fig. 1 is a schematic diagram of a diversity receiving system suitable for coherent laser communication according to the present invention;
FIG. 2 is a schematic diagram of a phase noise compensation module;
fig. 3 is a schematic structural diagram of a coherent combining module.
The reference numerals and corresponding part names in the drawings: 1. the device comprises an optical amplifier, 2, 90-degree optical mixers, 3, a homodyne coherent receiver, 4, a balance detector, 5, a phase noise compensation module, 6, a coherent combination module, 51, a low-pass filtering module, 52, an analog-to-digital conversion module, 53, a phase recovery algorithm module, 54, a signal judgment module, 61, a channel estimation module, 62, a matched filtering module, 63, a phase synchronization module, 64, a time delay synchronization module, 65 and an adder.
Detailed Description
The present invention will be described in further detail with reference to examples and drawings, but embodiments of the present invention are not limited thereto.
Example 1
As shown in fig. 1 to 3, the present invention aims to reduce the implementation complexity of a diversity receiving system, and proposes a diversity receiving system suitable for coherent laser communication. The system is characterized in that a homodyne coherent optical receiver of a main branch is used for compensating the problem of larger frequency difference faced by coherent laser communication, local oscillation light is output for coherent detection of each branch, and then a phase compensation technology and a coherent combination technology are utilized for realizing diversity reception of multipath signals, so that the influence of channel effects such as atmospheric turbulence and the like is inhibited. Because only a single-branch homodyne coherent receiver, low-complexity phase compensation and a multipath signal synchronization and combination algorithm are needed, the implementation cost and the technical complexity of diversity reception on a coherent laser communication system are reduced.
A diversity receiving system suitable for coherent laser communication comprises a main branch, a branch and a coherent combining module.
Further, the main branch is constituted by an optical amplifier 1, a 90 ° optical mixer 2, and a homodyne coherent optical receiver 3. The output port of the optical amplifier 1 is connected with the local oscillation optical input port of the 90-degree optical mixer 2, the output port of the 90-degree optical mixer 2 is connected with the input port of the homodyne coherent optical receiver 3, the local oscillation light output by the homodyne coherent optical receiver 3 is connected with the input port of the optical amplifier 1, and the output digital signal is connected with the coherent combining module 6.
Further, the branching circuit (for simplifying the analysis, the present invention is illustrated by 2 branching circuits, and more branching circuits can be generalized) is composed of the 90 ° optical mixer 2, the balance detector 4, and the phase noise compensation module 5. The output port of the optical amplifier 1 of each branch circuit is connected with the local oscillation optical input port of the 90-degree optical mixer 2, the output port of the 90-degree optical mixer 2 is connected with the input port of the balance detector 4, the output port of the balance detector 4 is connected with the input port of the phase noise compensation module 5, and the output signal of the output of the phase noise compensation module 5 is connected with the input port of the coherent combining module 6;
further, after the digital signals of the main branch and the digital signals of the branch are processed in the coherent combining module 6, the digital signals received by diversity are output, so that the diversity reception of coherent laser communication is realized.
The light field scalar of the first signal light, the second signal light and the third signal light are respectively:
wherein the frequencies of the signal lights are omega s The method comprises the steps of carrying out a first treatment on the surface of the The optical powers are respectively
The optical phases are phi respectively s1 (t)、φ s2 (t)、φ s3 (t). Due to the influence of the atmospheric channel, the optical power of each optical signal undergoes time-invariant, mutually independent slow fading, attenuation and the like, while the optical phase undergoes mutually independent phase distortion, random phase fluctuation and the like.
The light field scalar of the local oscillator light is:
wherein the optical power is
Optical phase is phi LO (t)。
After the homodyne coherent receiver of the main branch and the first signal light are subjected to coherent mixing, the frequency and the phase of the local oscillator light are kept consistent with those of the first signal light through optical phase locking, namely:
the homodyne coherent receiver demodulates the digital baseband signal and distributes the local oscillation light for coherent detection of the second signal light and the third signal light. Therefore, the photocurrent signal output by the balanced detector (taking in-phase I-path as an example) of the branch is:
wherein R is the responsivity of the balanced detector, phi 20 (t)、φ 30 (t) local oscillation light passing through the separation fiber, the optical amplifier and 90 respectively 0 The optical mixer is then shifted from the additional phase generated by the second signal light and the third signal light.
The invention relates to a diversity receiving system suitable for coherent laser communication, which comprises the following steps:
step one: and framing the transmitted data and pilot frequency according to the characteristics of the atmospheric channel.
Step two: on the main branch, the first signal light and the local oscillation light (amplified by an optical amplifier) are subjected to coherent mixing on a 90-degree optical mixer, and then are connected to homodyne coherent light reception for optical phase locking. The main branch compensates the frequency difference (compensation magnitude is GHz) between the local oscillation light and the signal light, the output local oscillation light is distributed to the coherent detection for each branch, and the digital signal is demodulated and output.
Step three: on the branch circuit, the second signal light, the third signal light and the local oscillation light are subjected to coherent mixing on a 90-degree optical mixer, are converted into an optical voltage signal with phase deviation through balanced detection, and then are connected into a phase noise recovery module to carry out low-pass filtering, analog-to-digital conversion, phase noise compensation, signal judgment and other processes, and stable digital signals are generated.
Step four: the digital signals generated by the main branch and each branch are respectively connected to a coherent combining module, channel estimation, matched filtering and phase-delay compensation of each signal are carried out according to pilot frequency of each frame of data, and finally the combined digital signals are output through an adder, so that diversity reception of coherent laser communication is realized.
Compared with the prior art, the invention has the advantages that:
(1) The invention can be directly applied to spatial coherent laser communication, atmospheric laser communication and the like, and greatly reduces the system error rate of laser communication, thereby improving the link reliability of laser communication;
(2) In the invention, the homodyne coherent receiver of the main branch circuit uses an optical phase locking technology to compensate larger frequency difference between signal light and local oscillation light, and outputs the local oscillation light to be supplied to other branch circuits for coherent detection, thereby avoiding the repeated use of complex optical phase locking technology by other branch circuits;
(3) In the invention, the local oscillation light and the signal light of the branch have no frequency difference and only have residual phase deviation, thereby avoiding the troublesome problems of simultaneously compensating larger frequency difference, random phase deviation and the like in digital coherent reception, and demodulating the digital signal by a simple phase noise compensation algorithm, and having low design difficulty and low power consumption;
(4) In the invention, the coherent combining module adopts the technologies of channel estimation, phase synchronization, time delay synchronization and the like to realize the coherent combining of multiple paths of signals, and has strong environmental adaptability and low implementation complexity;
(5) The invention can realize diversity reception under different atmosphere channel conditions by flexibly adjusting the pilot frequency quantity of the data frame;
(6) The invention adopts transparent modulation format, compatible with homodyne coherent reception and diversity reception of high-order modulation formats such as on-off keying (OOK), binary phase keying modulation (BPSK), differential Phase Shift Keying (DPSK), quaternary Quadrature Phase Shift Keying (QPSK), quadrature Amplitude Modulation (QAM) and the like;
(7) The invention belongs to mixed homodyne (analog) coherent receiving and digital coherent receiving technology, uses mature commercial devices, has simple combination mode and is easy to popularize to diversity receiving of multiple paths (N > 3).
Example 2
As further optimization of embodiment 1, as shown in fig. 1 to 3, this embodiment further includes the following technical features on the basis of embodiment 1:
referring to FIG. 1, the present invention provides a diversity receiving system suitable for coherent laser communication, which comprises optical amplifiers 1, 90 0 An optical mixer 2, a homodyne coherent optical receiver, a balance detector 4, a phase noise compensation module 5 and a coherent combining module 6. In this example, the working center wavelength is 1550nm, the output saturated optical power of the optical amplifier 1 is 40mw, the 900 optical mixer 2 outputs I, Q two paths of mixed optical signals, and the balance detector 4 (with the bandwidth of 10 GHz) is respectively used on two paths of I, Q, and the phase noise compensation module 5 and the coherent combining module 6 both support high-speed signals of DC-10 Gbps.
The homodyne coherent optical receiver is positioned in the main branch. For the main branch, the first signal light and the local oscillation light amplified by the optical amplifier 1 are coherently mixed on the 900 optical mixer 2, homodyne coherent demodulation is carried out by the homodyne coherent optical receiver, and not only digital signals are demodulated, but also local oscillation light is output and supplied to other branches for coherent reception. The homodyne coherent receiver adopts an optical phase locking technology, and can ensure that the frequency and the phase of local oscillation light are the same as those of signal light, thereby solving the problem of larger frequency difference in coherent optical communication. In the example, the homodyne coherent receiver supports coherent demodulation of DC-10GHz BPSK signals, the central wavelength of the output local oscillation laser is 1550nm, the tuning range is up to 40GHz, and the frequency difference range of space laser communication is covered. The modulation format of the signal is BPSK, the total length of each frame of data is 2048 bits, and the communication rate is 10Gbps
The phase noise compensation module 5 is positioned in the branch circuit. For the branch circuits, the second signal light, the third signal light and the like are respectively 90 times with the local oscillation light after passing through the optical amplifier 1 0 Coherent mixing is carried out on the optical mixer 2, and after the coherent mixing is converted into an optical voltage signal by a balance detector, a digital signal is recovered by adopting a phase noise compensation module 5. Although the frequency of the local oscillation light generated by the main branch is the same as that of the signal light, the random phase deviation is introduced by the optical amplifier, the 900 optical mixer, the separated optical fiber device and the like, and the phase deviation can be corrected by adopting a traditional phase noise recovery algorithm, and stable digital signals are demodulated.
The digital signals of the main branch and each branch are processed by a coherent combining module 6 such as channel estimation, matched filtering, phase synchronization, time delay synchronization and the like and then are connected to an adder, so that combined output can be realized, and multi-channel signal synchronization and diversity reception of coherent laser communication can be realized.
As described above, the diversity receiving system realizes coherent reception and coherent combining output of multipath optical signals, and can further improve diversity gain by increasing the number of branches (N > 3).
Referring to fig. 2, a schematic diagram of a phase noise compensation module of each branch is shown, which implements functions of a low-pass filtering module 51, an analog-to-digital conversion module 52, a phase recovery algorithm module 53, a signal decision module 54, and the like. Although the frequency of the local oscillation light generated by the homodyne coherent receiver of the main branch is the same as that of the signal light, the local oscillation light introduces random phase deviation after passing through an optical amplifier, a 900 optical mixer, a separation optical fiber and the like, so that the mixed optical voltage signal generates random fluctuation, and the correction can be carried out by adopting a phase shifter, an optical phase locking algorithm, a phase recovery algorithm and the like. In order to reduce the implementation complexity, the invention adopts a phase recovery algorithm, firstly carries out low-pass filtering processing on the photovoltage signals output by the balance detector, then adopts a classical phase noise compensation algorithm (comprising maximum likelihood phase estimation, M times of multiplication and the like) to correct the phase deviation, and outputs stable digital signals after signal judgment. Wherein, since the rate of change of the optical phase (ms level) can be considered as a slow-change process with respect to a high-speed modulation signal (ns level), the phases of the plurality of symbols before and after can be averaged to obtain a phase estimate. In this example, the bandwidth of the low-pass filter is 10GHz, the phase noise compensation algorithm adopts a mode of combining 2 times of multiplication with a digital phase-locked loop, and the signal judgment adopts a soft judgment mode.
Referring to fig. 3, a schematic diagram of a coherent combining module is shown, which implements functions such as a channel estimation module 61, a matched filtering module 62, a phase synchronization module 63, a delay synchronization module 64, and an adder 65. Each path of digital signal carries out channel estimation according to pilot frequency, carries out matched filtering, then carries out phase synchronization and time delay synchronization processing by taking a main branch as a reference, and finally inputs the signals to an adder to realize coherent combination. The length of the pilot sequence used for channel estimation is approximately 1/10 to 1/5 of the data length, depending on the channel characteristics of the atmosphere and the requirements of high-speed laser communication. Because the coherence time of the atmospheric channel is 1-10ms and the communication rate is as high as 1-10Gbps, the atmospheric channel can be considered to belong to a slow-change channel, and the atmospheric channel estimation can be completed according to 5ms intervals. After matched filtering processing, the signal to noise ratio of each path of signal reaches the maximization. In phase synchronization and time delay synchronization, a main branch is taken as a reference, phase offset correction and timing synchronization are carried out by combining a pilot sequence, and the phase offset correction and timing synchronization are output to a digital adder to carry out coherent superposition of baseband digital signals. In the example, the processing of the multipath digital signals adopts a pipeline mode of an FPGA to realize high-speed parallelism, the phase offset correction adopts an IP core of Xilinx, and the timing synchronization adopts a sliding related thought. The coherent combining module estimates the amplitude and phase information of each branch based on pilot frequency, and outputs a digital baseband channel by adopting digital coherent combination, thereby realizing the optimal diversity receiving gain.
Thus far, the present specification completes a detailed description of a diversity reception system suitable for coherent laser communication. What is not described in detail in the present specification belongs to the known technology of those skilled in the art.
As described above, the present invention can be preferably implemented.
All of the features disclosed in all of the embodiments of this specification, or all of the steps in any method or process disclosed implicitly, except for the mutually exclusive features and/or steps, may be combined and/or expanded and substituted in any way.
The foregoing description of the preferred embodiment of the invention is not intended to limit the invention in any way, but rather to cover all modifications, equivalents, improvements and alternatives falling within the spirit and principles of the invention.
Claims (10)
1. The diversity receiving system suitable for coherent laser communication is characterized by comprising a main branch, N branch circuits and a coherent combining module (6), wherein the main branch circuits, the N branch circuits and the coherent combining module are arranged side by side, the N branch circuits are sequentially increased according to the numbers of the directions from the near to the far of the main branch circuits, and are respectively recorded as 1,2, i, N; the main branch comprises an optical amplifier (1), a 90-degree optical mixer (2) and a homodyne coherent optical receiver (3) which are sequentially connected, each branch comprises the optical amplifier (1) and the 90-degree optical mixer (2) which are sequentially connected, each 90-degree optical mixer (2) is provided with one path of optical signal input, the output end of each branch and the output end of each phase noise compensation module (5) are respectively connected with the input end of the coherent combining module (6), and the output end of the homodyne coherent optical receiver (3) is also respectively connected with the input end of each 90-degree optical mixer (2); wherein i represents the number of the branch, i is more than 1 and less than or equal to N, N is more than or equal to 2, and i and N are integers.
2. A diversity receiving system adapted for coherent laser communication according to claim 1, characterized in that each branch further comprises a balanced detector (4), in each branch the optical amplifier (1), the 90 ° optical mixer (2), the balanced detector (4) being connected in sequence.
3. A diversity receiving system adapted for coherent laser communication according to claim 2, characterized in that each branch further comprises a phase noise compensation module (5), in each branch the optical amplifier (1), the 90 ° optical mixer (2), the balanced detector (4) and the phase noise compensation module (5) are connected in sequence.
4. A diversity receiving system adapted for coherent laser communication according to claim 3, characterized in that the phase noise compensation module (5) comprises a low-pass filtering module (51), an analog-to-digital conversion module (52), a phase recovery algorithm module (53) and a signal decision module (54) which are connected in sequence, the output end of the signal decision module (54) being connected with the input end of the coherent combining module (6).
5. A diversity receiving system adapted for coherent laser communication according to claim 4, characterized in that the coherent combining module (6) comprises K coherent branches, an adder (65), each coherent branch comprising a channel estimation module (61), a matched filtering module (62) connected to each other, the output of each matched filtering module (62) being connected to the input of the adder (65), respectively; wherein K is more than or equal to 2 and K is an integer.
6. A diversity receiving system adapted for coherent laser communication according to claim 5, characterized in that the coherent combining module (6) further comprises a phase synchronizing module (63), the input of the phase synchronizing module (63) being connected to the output of each matched filter module (62) respectively, the output of the phase synchronizing module (63) being connected to the input of the adder (65).
7. A diversity receiving system adapted for coherent laser communication according to claim 6, characterized in that the coherent combining module (6) further comprises a delay synchronization module (64), the input of the delay synchronization module (64) being connected to the output of the phase synchronization module (63), the output of the delay synchronization module (64) being connected to the input of the adder (65).
8. A diversity receiving system adapted for coherent laser communication according to any of claims 1 to 7, characterized in that the signal modulation format of the homodyne coherent optical receiver (3) is BPSK and transparent to the modulation format.
9. A diversity receiving system adapted for coherent laser communication according to claim 8, wherein N = 2.
10. The diversity receiving system for coherent laser communication according to claim 9, wherein the center wavelength of the local oscillation laser outputted from the homodyne coherent optical receiver (3) is 1550nm, and the tuning range is up to 40GHz.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116856920A (en) * | 2023-07-06 | 2023-10-10 | 中国科学院地质与地球物理研究所 | Application method and instrument of azimuth electromagnetic wave resistivity while drilling instrument |
| CN117420770A (en) * | 2023-12-01 | 2024-01-19 | 上海频准激光科技有限公司 | Data simulation system for multipath laser control |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102318306A (en) * | 2009-03-02 | 2012-01-11 | 株式会社日立制作所 | Optical multi-level transmission system |
| CN105610565A (en) * | 2015-12-21 | 2016-05-25 | 武汉邮电科学研究院 | Self-correlation zero-difference detection apparatus and method based on mode multiplexing optical communication system |
| US20200382217A1 (en) * | 2019-05-29 | 2020-12-03 | Elenion Technologies, Llc | Coherent optical receiver |
-
2022
- 2022-12-27 CN CN202211683760.8A patent/CN116054956B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102318306A (en) * | 2009-03-02 | 2012-01-11 | 株式会社日立制作所 | Optical multi-level transmission system |
| CN105610565A (en) * | 2015-12-21 | 2016-05-25 | 武汉邮电科学研究院 | Self-correlation zero-difference detection apparatus and method based on mode multiplexing optical communication system |
| US20200382217A1 (en) * | 2019-05-29 | 2020-12-03 | Elenion Technologies, Llc | Coherent optical receiver |
Non-Patent Citations (2)
| Title |
|---|
| J. VENTURA-TRAVESET: "Impact of diversity reception on fading channels with coded modulation. I. Coherent detection", 《 IEEE TRANSACTIONS ON COMMUNICATIONS 》, 31 May 1997 (1997-05-31) * |
| 林贻翔;: "液晶多波束光学相控阵技术", 光通信技术, no. 09, 15 September 2018 (2018-09-15) * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116856920A (en) * | 2023-07-06 | 2023-10-10 | 中国科学院地质与地球物理研究所 | Application method and instrument of azimuth electromagnetic wave resistivity while drilling instrument |
| CN116856920B (en) * | 2023-07-06 | 2024-04-02 | 中国科学院地质与地球物理研究所 | Application method and instrument of azimuth electromagnetic wave resistivity while drilling instrument |
| CN117420770A (en) * | 2023-12-01 | 2024-01-19 | 上海频准激光科技有限公司 | Data simulation system for multipath laser control |
| CN117420770B (en) * | 2023-12-01 | 2024-04-26 | 上海频准激光科技有限公司 | Data simulation system for multipath laser control |
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