Broadband Laser Doppler Frequency Shift Emulator for Satellite Laser Communication

Jinye Li,Jianguo Liu,Jiaqing Hou,Guozhang Wu,Bo Liu,Yuan Yao,Wenqi Yu

doi:10.1109/jphot.2019.2956075

Abstract

A novel emulator of laser Doppler frequency shift (DFS) for satellite laser communication based on microwave photonics technology is proposed and experimentally demonstrated. In order to overcome the bottleneck that the optical frequency shift signal with a wide frequency offset from near zero can hardly be obtained using traditional electro-optic or acousto-optic frequency shifting, the frequency of laser signal is first moved to a lower/higher fixed frequency and then shifted back to a higher/lower tunable frequency. The signal after cascaded frequency shifting in the opposite direction is equivalent to the original laser signal with DFS. In the experiment, the value and direction of DFS correspond to the magnitude and sign of the difference between the two frequency shifts. The DFS from −14 GHz to +14 GHz with a varying rate of 323 MHz/s is accurately implemented. In addition, the side mode suppression ratio (SMSR) of laser signals with DFS are all over 52.3 dB. The proposed scheme is significant to evaluate and test the DFS compensation capability of the satellite laser communication terminal.

Highlights

Satellite laser communication has become one hot topic in recent years due to its intrinsic merits of high data rate, strong immunity to electromagnetic interference, small antenna size and low power consumption [1]–[3]
In this paper we propose an emulator to form high spectral quality, broadband and fast laser Doppler frequency shift (DFS) for any satellite orbit based on electro-optic cascaded frequency shifting in the opposite direction
A continuous light wave with a power of 13 dBm and wavelength around 1550.52 nm is generated from a laser diode (LD) and injected into the Mach-Zehnder modulator (MZM) (Photline, MXAN-20) via a polarization controller (PC)

Summary

Introduction

Satellite laser communication has become one hot topic in recent years due to its intrinsic merits of high data rate, strong immunity to electromagnetic interference, small antenna size and low power consumption [1]–[3]. Carrier suppressed single sideband modulation (CS-SSB) is implemented to tune multiwavelength fiber laser precisely by using a dual-parallel Mach-Zehnder modulator (DPMZM), and the maximum side mode suppression ratio (SMSR) between the ±1st order components is 20.59 dB [9]. In [10], the frequency shift based on CS-SSB modulation is achieved by combining carrier suppression double sideband modulation (CS-DSB) of DPMZM with an optical band-pass filter (OBPF), and the power ratio of the +1st order optical signal to optical carrier is 23 dB. In this paper we propose an emulator to form high spectral quality, broadband and fast laser DFS for any satellite orbit based on electro-optic cascaded frequency shifting in the opposite direction. The side mode suppression ratios (SMSR) of laser signals with DFS are all over 52.3 dB

Principle

Experiments and Results

Conclusion