US 12,411,208 B2
Coherent microwave photonics radar detection method and system based on injection locking frequency multiplication
Qingshui Guo, Hangzhou (CN); Kun Yin, Hangzhou (CN); Chen Ji, Hangzhou (CN); Jihou Wang, Hangzhou (CN); and Xiaojun Ying, Hangzhou (CN)
Assigned to ZHEJIANG LAB, Hangzhou (CN)
Filed by ZHEJIANG LAB, Zhejiang (CN)
Filed on Dec. 26, 2022, as Appl. No. 18/088,743.
Application 18/088,743 is a continuation of application No. PCT/CN2021/126522, filed on Oct. 26, 2021.
Claims priority of application No. 202110765357.9 (CN), filed on Jul. 7, 2021.
Prior Publication US 2023/0136882 A1, May 4, 2023
Int. Cl. G01S 13/34 (2006.01); G01S 7/35 (2006.01); G01S 13/02 (2006.01)
CPC G01S 7/354 (2013.01) [G01S 13/0209 (2013.01); G01S 13/34 (2013.01)] 7 Claims
OG exemplary drawing
 
4. A coherent microwave photonics radar detection system based on injection locking frequency multiplication, comprising:
a master laser configured to generate an optical carrier signal fc;
a signal source configured to generate a baseband linear frequency modulation (LFM) signal with a frequency of fLFM,
a first electro-optic modulator configured to modulate a baseband LFM signal to the optical carrier signal to obtain a modulated optical signal containing a high-order modulation sideband fC±nfLFM, where n is a positive integer;
a first optical coupler configured to divide the modulated optical signal into two paths;
two slave lasers configured to respectively receive the two paths of the modulated optical signal output by the first optical coupler, and filter, lock and amplify a specific sideband of the modulated optical signal to obtain a first amplified locked sideband signal fC−MfLFM and a second amplified locked sideband signal fC+NfLFM, where M and N are positive integers;
a second optical coupler configured to combine the first amplified locked sideband signal fC−MfLFM and the second amplified locked sideband signal fC+NfLFM output by a third optical coupler into a radar detection optical signal, which is then divided into two paths to be sent to a 90-degree optical coupler and a photoelectric detector, respectively;
the third optical coupler configured to divide the second amplified locked sideband signal fC+NfLFM into two paths and send the two paths to a second electro-optic modulator and the second optical coupler, respectively;
a photodetector configured to carry out photoelectric conversion on the radar detection optical signal to obtain a frequency multiplication radar transmitting signal;
a power amplifier and a transmitting antenna configured to perform power amplification and signal transmission for the frequency multiplication radar transmitting signal;
a receiving antenna and a low noise amplifier configured to receive a radar echo signal and perform low noise amplification;
the second electro-optic modulator configured to modulate one path of an amplified locked sideband signal output by the third optical coupler using the radar echo signal to obtain a radar receiving optical signal and send the radar receiving optical signal to the 90-degree optical coupler;
the 90-degree optical coupler configured to introduce a 90-degree phase difference between an input radar detection optical signal and the radar receiving optical signal in an optical domain, and output four paths of composite optical signals;
two balanced photodetectors configured to respectively carry out photoelectric detection on the four paths of optical signals output by the 90-degree optical coupler to obtain two paths of orthogonal intermediate frequency signals carrying target information; and
a signal acquisition and processing module configured to perform analog-to-digital conversion for the two paths of orthogonal intermediate frequency signals, and perform radar digital signal processing to extract the target information.