Cost-effective photonics-based THz wireless delivery system using a directly modulated DFB-LD

• Published in: Optics communications Vol. 492; p. 126969
• Main Authors: Kim, Eon-sang, Moon, Sang-rok, Sung, Minkyu, Lee, Han Hyub, Lee, Joon Ki, Cho, Seung-hyun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2021
• Subjects: Directly modulated laser (DML); Laser-to-filter detuning effect; Optical communication; Terahertz communication; Optical communication; Terahertz communication; Directly modulated laser (DML); Laser-to-filter detuning effect
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2021.126969

We present a cost-effective photonics-based THz wireless delivery system using a directly modulated distributed feedback laser diode (DFB-LD). A DFB-LD with non-return to zero (NRZ) modulation up to 25 Gbps and a uni-traveling-carrier photodiode (UTC-PD) with a horn antenna is employed to transmit a THz wave into free space in the photonics-based THz signal transmitter. A Schottky barrier diode (SBD) with a horn antenna is used to directly detect the THz wave from free space at the THz signal receiver. To achieve the best bit error rate performance, we varied the optimal THz carrier frequency in a photonics-based THz wireless delivery system. After THz carrier frequency optimization, bit error rates were measured by varying THz link operating conditions, such as the data rate, photocurrent of UTC-PD, and wireless transmission distance. We successfully transmitted a 25 Gb/s NRZ signal over 1.6 and 2.2 m wireless transmission distances before and after managing the adiabatic chirp characteristic of directly modulated DFB-LD using the laser-to-filter detuning effect, respectively, while satisfying the 7% hard decision-forward error correction (HD-FEC) threshold (3.4×10−3). •The adiabatic-chirp management is applied to improve the BER performance in DML based THz wireless delivery system.•We derive the optimum laser-to-filter detuned frequency in the DML based THz wireless link.•We experimentally analyze the transmission performance of the link before and after managing the adiabatic-chirp of directly modulated DFB-LD.