Title :
Photonic Generation of Tunable Continuous-Wave Microwave Signals Using a Temporally-Stretched and Chirped Pulse-Train
Author :
Wong, Jia Haur ; Lam, Huy Quoc ; Aditya, Sheel ; Lee, Kenneth Eng Kian ; Wong, Vincent ; Lim, Peng Huei ; Wu, Kan ; Ouyang, Chunmei ; Shum, Perry Ping
Author_Institution :
Electr. & Electron. Eng. Dept., Nanyang Technol. Univ., Singapore, Singapore
fDate :
5/1/2012 12:00:00 AM
Abstract :
We show analytically and experimentally that direct photodetection of a temporally-stretched and chirped optical pulse-train together with its time-delayed replica can be exploited to realize the generation of tunable continuous-wave microwave signals. The proposed scheme utilizes the chromatic dispersion of the standard single-mode-fiber (SMF) to temporally-stretch and chirp an optical pulse-train in such a way that the pulses overlap with each other. The temporally-stretched pulse-train is then sent to a Mach-Zehnder Interferometer (MZI) where it first splits and then recombines with a time-delayed replica of itself at the output. Proper management of both the dispersion in the system as well as the relative time-delay of the two arms of the MZI enables one to tune the frequency of the generated microwave signal to any integer multiple of the pulse source´s repetition frequency which is within the bandwidth of the photodetector. Based on the proposed scheme, using an initial 2 GHz pulse-train, we demonstrate generation of tunable continuous-wave microwave signals from 4 GHz to 14 GHz.
Keywords :
Mach-Zehnder interferometers; microwave photonics; optical pulse generation; photodetectors; Mach-Zehnder Interferometer; chirped optical pulse-train; chromatic dispersion; frequency 2 GHz; frequency 4 GHz to 14 GHz; photodetection; photodetector; photonic generation; standard single-mode-fiber; temporally-stretched pulse-train; tunable continuous-wave microwave signals generation; Chirp; Masers; Microwave circuits; Microwave communication; Microwave filters; Microwave photonics; Microwave photonics; fiber optics; microwave signal generation; mode-locked fiber laser;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2012.2184263