Monolithically Integrated Dual-Wavelength Distributed Bragg Reflector Laser Photonic Integrated Circuit Chip for Continuous-Wave Terahertz Generation

Qianwen Guo,Mengdie Sun,Ruoyun Yao,Wanshu Xiong,Chen Ji,Ronald Broeke,Dan Lu,Qiulu Yang

doi:10.1109/jphot.2021.3062835

Abstract

We report the design, fabrication and characterization of a 1.55-μm dual-wavelength Distributed Bragg Reflector (DBR) laser photonic integrated circuit (PIC) chip for continuous-waves (CW) terahertz generation. The PIC chip consists of a pair of parallel DBR lasers with integrated semiconductor optical amplifiers (SOA), and a multimode interference (MMI) coupler for combining the two wavelength channels into a single output waveguide. A room temperature continuous wave THz tuning range of 0.06 THz - 0.71 THz was obtained through optical heterodyne technique.

Highlights

Technologies for the generation of electromagnetic radiations operating in the Terahertz (THz) have been developing at a rapid pace over the past two decades, overcoming the traditional challenges of the “Terahertz Gap”, due to a broad range of emerging applications in THz sensing, THz spectroscopy, THz imaging, nondestructive material inspections, and THz wireless data communications [1]-[5]
Electronic approaches are typically limited by the requirement of bulky and expensive equipment, tend to operate at a fixed THz signal frequency with low efficiency, and lacking the ability for room temperature continuous frequency tuning that is a key requirement for many THz applications
We have demonstrated a monolithic 1.55-μm dual-wavelength optical heterodyne photonic integrated circuit (PIC) chip for THz generation, integrating two distributed Bragg reflector (DBR) lasers, semiconductor optical amplifiers (SOAs), and a multimode interference (MMI) coupler on the same InP-based substrate

Summary

Introduction

Technologies for the generation of electromagnetic radiations operating in the Terahertz (THz) have been developing at a rapid pace over the past two decades, overcoming the traditional challenges of the “Terahertz Gap”, due to a broad range of emerging applications in THz sensing, THz spectroscopy, THz imaging, nondestructive material inspections, and THz wireless data communications [1]-[5]. A photonic based process, provides a simple and efficient technique for generating broadly tunable THz wave radiation at room temperature. While optical heterodyne experiments traditionally use two separate external solid laser sources, in recent years, THz generation by the optical heterodyning method based on dual-mode semiconductor lasers [9]-[15] attracts researchers’ attention for its unique advantages such as low cost, wide continuous tuning range, room temperature operation, and the potentials for monolithic integration resulting in a very compact form factor chip solution that can be volume manufactured through standard semiconductor processing technologies. We report THz wave generation with a record room temperature continuous tuning range from 0.06 THz to 0.71 THz for a dual DBR monolithic PIC chip, demonstrating the potentials of our PIC chip for future high-volume and low-cost THz applications

Device design and fabrication

Results and Discussions

Conclusion