Photonics-Based Single Sideband Mixer With Ultra-High Carrier and Sideband Suppression

Chongjia Huang,Erwin H W Chan

doi:10.1109/jphot.2021.3089575

Abstract

A photonics-based frequency mixer for up converting an IF signal into an RF signal with very large suppression in the carrier and the sideband is presented. The mixer is filter free and has a simple structure. It enables off-the-shelf bias controllers to be incorporated into the system. This solves the problem of the carrier and sideband suppression reduces with time that is present in all reported photonics-based single sideband mixers. Experiments are conducted to verify the proposed mixer structure. Results show the single sideband mixer generates an up converted RF signal with more than 40 dB suppression in the carrier and sideband over a wide frequency range. This is a 10-dB improvement compared to the reported structures. A conversion efficiency of around -6 dB is attained, which is over 10 dB higher than the reported structures. Frequency up conversion of an IF signal with a band of frequency and a long-term stable performance are also demonstrated.

Highlights

F REQUENCY mixer is a key component in radars, instruments and communication systems
We present a photonics-based single sideband (SSB) mixer that largely improves both the carrier and sideband suppression and the conversion efficiency of the reported structures
A new photonics-based frequency mixer has been presented which addresses the issue of limited carrier and sideband suppression in the reported SSB mixer structures

Summary

INTRODUCTION

F REQUENCY mixer is a key component in radars, instruments and communication systems. A SSB mixer is used for up converting an IF signal with a frequency of fIF into an RF signal at the frequency of either fLO+fIF or fLO-fIF where fLO is the frequency of the LO into the mixer It reduces the system cost and complexity by eliminating the need of using a filter to remove one sideband. We present a photonics-based SSB mixer that largely improves both the carrier and sideband suppression and the conversion efficiency of the reported structures. It is filter free and has a simple single-laser, single-integrated-modulator and single-photodetector structure. Experimental results are presented which demonstrate wideband SSB frequency mixing operation with around 10 dB improvement in both the carrier and sideband suppression and the conversion efficiency compared to the reported structures. SSB frequency up conversion of a 200 Mbps pseudo random binary sequence (PRBS) signal with around 40 dB carrier and sideband suppression and a long-term stable performance obtained using bias controllers in the setup are demonstrated

TOPOLOGY AND OPERATION PRINCIPLE

SIMULATION RESULTS AND DISCUSSION

EXPERIMENTAL RESULTS

CONCLUSION