Open AccessSOA‐Integrated Dual‐Mode Laser and PIN‐Photodiode for Compact CW Terahertz System
Author(s) -
Lee Eui Su,
Kim Namje,
Han SangPil,
Lee Donghun,
Lee WonHui,
Moon Kiwon,
Lee IlMin,
Shin JunHwan,
Park Kyung Hyun
Publication year - 2016
Publication title -
etri journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 46
eISSN - 2233-7326
pISSN - 1225-6463
DOI - 10.4218/etrij.16.0115.0882
Subject(s) - photodiode , materials science , optoelectronics , terahertz radiation , laser , optics , common emitter , amplifier , physics , cmos
We designed and fabricated a semiconductor optical amplifier‐integrated dual‐mode laser (SOA‐DML) as a compact and widely tunable continuous‐wave terahertz (CW THz) beat source, and a pin‐photodiode (pin‐PD) integrated with a log‐periodic planar antenna as a CW THz emitter. The SOA‐DML chip consists of two distributed feedback lasers, a phase section for a tunable beat source, an amplifier, and a tapered spot‐size converter for high output power and fiber‐coupling efficiency. The SOA‐DML module exhibits an output power of more than 15 dBm and clear four‐wave mixing throughout the entire tuning range. Using integrated micro‐heaters, we were able to tune the optical beat frequency from 380 GHz to 1,120 GHz. In addition, the effect of benzocyclobutene polymer in the antenna design of a pin‐PD was considered. Furthermore, a dual active photodiode (PD) for high output power was designed, resulting in a 1.7‐fold increase in efficiency compared with a single active PD at 220 GHz. Finally, herein we successfully show the feasibility of the CW THz system by demonstrating THz frequency‐domain spectroscopy of an α‐lactose pellet using the modularized SOA‐DML and a PD emitter.