Open AccessPhotonic Armstrong method enabled by direct detection for wideband electrical PM generation
Author(s) -
Shota Ishimura,
Hsuan-Yun Kao,
Kazuki Tanaka,
Kosuke Nishimura,
Ryo Inohara,
Takehiro Tsuritani,
Masatoshi Suzuki
Publication year - 2021
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.417640
Subject(s) - photonics , bandwidth (computing) , narrowband , wideband , broadband , frequency multiplier , computer science , electronic engineering , optics , signal processing , signal (programming language) , physics , radar , telecommunications , engineering , programming language
Wideband signal generation using frequency/phase modulation (FM/PM) is the key fundamental function for various applications such as radar and analog communication systems. It is well known that analog FM/PM communication systems can dramatically improve signal quality by spectral expansion. In classical communication theories, the Armstrong indirect method is one of the most popular methods for bandwidth expansion of FM signals. In the Armstrong method, a narrowband signal is converted to a broadband signal with the help of a nonlinear frequency multiplier. In this paper, we propose a photonic Armstrong method enabled by direct detection. By utilizing the nonlinearity caused by direct detection, we can increase bandwidth so that it is double that of the original signal in the photonic Armstrong method. Also, it completely eliminates signal-to-signal beat interference (SSBI) at the same time. We conducted an experiment to verify the concept and confirmed these advantages experimentally.