Coherent receiving device and anemometry lidar system

Patent metadata

Field	Value
Publication number	US-12567909-B2
Application number	US-202018252355-A
Country	US
Kind code	B2
Filing date	Dec 10, 2020
Priority date	Nov 11, 2020
Publication date	Mar 3, 2026
Grant date	Mar 3, 2026

Abstract

A coherent receiving device and anemometry lidar system. The device includes: a polarization maintaining optical fiber pin for receiving local oscillation light and outputting it to frequency mixer; a polarization beam splitting prism for receiving signal light, splitting it into first and second signal light, and outputting them to the frequency mixer; the frequency mixer for mixing the first and second signal light with the local oscillation light and outputting the mixed light to PD array; the PD array for converting the mixed light to differential current signal; and a signal processing circuit for converting the differential current signal to differential voltage signal whose derivation formula includes part of frequency difference between the signal light and local oscillation light, detecting a frequency of the differential voltage signal to obtain a value of the frequency difference, and obtaining Doppler frequency shift amount of the signal light according to the value.

First claim

What is claimed is:

1 . A coherent receiving device, comprising a polarization maintaining optical fiber pin, a polarization beam splitting prism, a frequency mixer, a photodiode (PD) array and a signal processing circuit,
wherein the polarization maintaining optical fiber pin is configured to receive local oscillation light and output the local oscillation light to the frequency mixer, a polarization state of the local oscillation light being kept unchanged when the local oscillation light is transmitted in the polarization maintaining optical fiber pin; the polarization beam splitting prism is configured to receive signal light, splitting the signal light into a first signal light with a p polarization state and a second signal light with an s polarization state, and outputting the first signal light and the second signal light to the frequency mixer; the frequency mixer is configured to mix the first signal light and the second signal light with the local oscillation light, respectively, and output mixed light to the PD array; the PD array is configured to perform photoelectric conversion on the mixed light to obtain a differential current signal; and the signal processing circuit is configured to convert the differential current signal so as to obtain a differential voltage signal, wherein a derivation formula of the differential voltage signal comprises a part of a frequency difference between the signal light and the local oscillation light; detect a frequency of the differential voltage signal so as to obtain a value of the frequency difference between the signal light and the local oscillation light; and obtain a Doppler frequency shift amount of the signal light according to the value of the frequency difference between the signal light and the local oscillation light, wherein the coherent receiving device further comprises two C lenses provided between the polarization beam splitting prism and the frequency mixer, wherein the first signal light and the second signal light output by the polarization beam splitting prism are respectively converged into the frequency mixer through the two C lenses.

2 . The coherent receiving device of claim 1 , wherein the signal processing circuit comprises an amplifier module, an analog-to-digital converter, and a processor;
wherein the amplifier module is configured to amplify the differential current signal and convert the differential current signal into the differential voltage signal; the analog-to-digital converter is configured to perform analog-to-digital converter ADC sampling on the differential voltage signal to obtain an ADC sampling signal; and the processor is configured to process the ADC sampling signal to obtain a frequency of the ADC sampling signal which is the Doppler frequency shift amount of the signal light.

3 . The coherent receiving device of claim 2 , wherein the derivation formula of the differential voltage signal is

X
I

=

R
×
G
×

P
in

×

(

cos
⁢
δ

)

2

×

P
lo

2

⁢

cos
⁡
(

(

ω
in

-

ω
lo

)

×
t

+

θ
in

-

θ
lo

)

⁢

and

X
Q

=

R
×
G
×

P
in

×

(

cos
⁢
δ

)

2

×

P
lo

2

⁢

sin
⁡
(

(

ω
in

-

ω
lo

)

×
t

+

θ
in

-

θ
lo

)

;

where R is responsivity of photodiode in the PD array; G is a trans-impedance gain of the amplifier module; P in is an optical intensity of the signal light; P lo is an optical intensity of the local oscillation light; ω in is an angle frequency of the signal light; ω lo is an angle frequency of the local oscillation light; θ in is an initial phase of the signal light; θ lo is an initial phase of the local oscillation light; δ is an intersection angle between the first s

Assignees

• Accelink Tech Co Ltd

Inventors

• Shi Chuan
• Zhang Bo
• Chen Honggang
• Liang Xuerui
• Cheng Xuanxuan

Classifications

• G01S17/58

  Velocity or trajectory determination systems; Sense-of-movement determination systems · CPC title

• G01S7/499

  using polarisation effects · CPC title

• G01S7/4917

  superposing optical signals in a photodetector, e.g. optical heterodyne detection · CPC title

• G01P5/26

  by measuring the direct influence of the streaming fluid on the properties of a detecting optical wave · CPC title

• H04B10/616

  Details of the electronic signal processing in coherent optical receivers · CPC title