UWB Fastly–Tunable 0.5–50 GHz RF Transmitter Based on Integrated Photonics

Claudio Porzi,Paolo Ghelfi,Fabio Falconi,Filippo Scotti,Antonio Malacarne,Antonella Bogoni

doi:10.1109/jlt.2021.3135861

Abstract

Currently, due to the 6G revolution, applications ranging from communication to sensing are experiencing an increasing and urgent need of software-defined ultra-wideband (UWB) and tunable radio frequency (RF) apparatuses with low size, weight, and power consumption (SWaP). Unfortunately, the coexistence of ultra-wideband and software-defined operation, tunability and low SWaP represents a big issue in the current RF technologies. Recently, photonic techniques have been demonstrated to support achieving the desired features when applied in RF UWB transmitters, introducing extremely wide operation and instantaneous bandwidth, tunable filtering, tunable photonics-based microwave mixing with very high port-to-port isolation, and intrinsic immunity to electromagnetic interferences. Moreover, the recent advances in photonics integration also allow to obtain very compact devices. In this article, to the best of our knowledge, the first example of a complete tunable software-defined RF transmitter with low footprint (i.e., on photonic chip) is presented exceeding the state-of-the-art for the extremely large tunability range of 0.5–50 GHz without any parallelization of narrower-band components and with fast tuning (<200 μs). This first implementation represents a breakthrough in microwave photonics.

Highlights

Due to the 6G revolution, applications ranging from communication to sensing are experiencing an increasing and urgent need of software-defined ultra-wideband (UWB) and tunable radio frequency (RF) apparatuses with low size, weight, and power consumption (SWaP)
RF equipment shall enable a large number of fundamental applications as UWB communications [2], robot localization mapping and control [3]‒[6] and high precision radars [7]‒[9], all of them contributing in revolutionizing our life style through breakthroughs in communications, in medicine, in security, in work processes (e.g., Industry 4.0), etc
A breakthrough implementation of a 0.5 ‒ 50 GHz tunable RF transmitter based on integrated photonics has been presented

Summary

RF TRANSMITTER ARCHITECTURE AND SINGLE COMPONENT

This modulation is obtained by means of a dual-parallel pn junctionbased Mach-Zehnder modulator (MZM) driven by the I and Q components of the waveform. The SSB-CS modulator and the tunable optical filter are the most critical components of the scheme which required a custom design The former one is responsible for providing a single sideband (the replica of the waveform in the optical domain) with excellent suppression of both the carrier and the second sideband, while the latter one shall select one line out of the full optical spectral comb with an excellent rejection. Details of the characterization of the two custom components (SSB-CS modulator and tunable optical filter) are reported

Single-Sideband Carrier-Suppression Modulator

Design specifications

SYSTEM-LEVEL EXPERIMENTAL RESULTS

SYSTEM PERFORMANCE AND DISCUSSION

CONCLUSION