Frequency Division Technology Based On An Optoelectronic Oscillator

Frequency division of microwave is the key technology to realize digital clock control and microwave frequency synthesis.It has been widely used in wireless communication,optical communication,satellite navigation,microwave imaging and radar detection.At present,with the rapid development of 5G / 6G communication technology,millimeter wave imaging technology,and terahertz technology,frequency division technologies such as analog and digital have been greatly challenged in terms of operating frequency and bandwidth.Compared with traditional microwave technology,photonics technology has the great advantages of large operating bandwidth,small transmission loss,and low noise.Aiming at the electronic bottleneck encountered by the traditional frequency division technology,this paper proposes and implements a microwave photonics frequency division system based on the optical carrier suppression technology based on the research on an optoelectronic oscillation loop,which achieves tens of GHz two and three frequency division signal generation,providing a new solution for high frequency,broadband and high-performance microwave frequency division.The main innovative work of this article is as follows:1.Propose a 1/2 frequency division scheme based on an optoelectronic oscillator(OEO).The Mach-Zehnder modulator(MZM)in the OEO is biased at the minimum transmission bias point(MITP)to achieve carrier-suppressed optical double sideband(CS-ODSB)modulation.This solution divides the frequency and avoids free oscillation of the optoelectronic loop.Under steady-state conditions,the microwave signal to be divided and the oscillating signal are respectively modulated by CS-ODSB to generate respective ±1st-order sidebands,and the difference frequency component thereof must be equal to the frequency of the oscillating signal,so as to achieve two frequency division of the microwave signal.The experimental results show that the scheme successfully divides the 12 GHz microwave signal into 6 GHz,and its phase noise is improved by 5.71 d B,which is in line with theoretical expectations.In addition,the broadband tunable performance of this scheme is also studied,and the working bandwidth can reach 6-10 GHz.2.Propose a 2/3 frequency division scheme based on an OEO.This solution is based on a cascaded MZM structure,and each MZM works at the MITP.The role of the first stage MZM is to generate a two-wavelength signal with a frequency interval of 2 times the input frequency.The second stage MZM is through the optoelectronic oscillation loop to make the system output frequency is converted to twothirds of the input frequency.The experimental results show that this scheme successfully divides the14.7 GHz microwave signal by 2/3 to 9.8 GHz,and its phase noise is improved by 3.27 d B,which is in line with the theoretical value.In addition,broadband tunability of 8.2-11.8 GHz is also achieved.3.Based on the above-mentioned frequency division technology,a 1/2,2/3 frequency division switchable scheme based on an OEO is also proposed.This solution adopts dual-parallel Mach-Zehnder modulator(DPMZM)to make DPMZM work at the MITP to achieve CS-ODSB modulation,and by adjusting the loop phase,switching between 1/2 and 2/3 frequency division signals is achieved.The experimental results show that the scheme successfully divides the 12.2 GHz microwave signal by 1/2and 2/3 respectively into 6.1 GHz and 8.13 GHz.In addition,its phase noise and broadband tunability performance are analyzed,and it is verified that the switching time is 3.5 ms.