Open AccessMethod for converting high-speed and spectrally efficient terahertz-wave signal into optical signal
Author(s) -
Koichi Takiguchi
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.006598
Subject(s) - optics , signal (programming language) , sideband , signal transfer function , optical filter , physics , radio frequency , analog signal , computer science , transmission (telecommunications) , telecommunications , programming language
A simple method, which converts a high-speed and spectrally efficient on-off keying (OOK) signal in the terahertz (THz)-band into an optical signal, is reported. In the proposed method, the THz-wave signal is down-converted into a radio-frequency (RF) signal, which is transferred to an optical signal through an optical intensity modulator. This modulator's bias is set to a null point. An extracted optical sideband from the modulator output corresponds to the converted optical signal. When the intermediate frequency (IF) of the RF signal is set to more than or equal to half of the signal bandwidth, the method enables us to carry out proper conversion. The method is adequate for a spectrally efficient signal because the IF can be set to a low value. To show the method's validity, calculation, and some experiments using a signal shaped with a root Nyquist optical filter were carried out.