In a microwave fiber wireless communication system, reducing optical carrier-to-sideband ratio can improve the receiving sensitivity and dynamic range of the system. However, at lower modulation frequencies corresponding to cellular radio (900 MHz), personal communication system (1.8 GHz) and IEEE 802.11g (2.4 GHz), separating the signals from the carrier and reducing carrier power in optic domain is a rather challenging task. In this paper, we have presented a new method to improve the transmission efficiency in microwave fiber-optic link by suppressing the optical carrier using a sub-picometer bandpass filter. The filter we designed and fabricated has a −3dB bandwidth of 120 MHz, capable of even filtering out a microwave signal as low as 900 MHz. We compared the transmission performance between filtered signals and unfiltered signals. The experimental results showed that the receiver sensitivity was improved significantly, 4.4dB for the 900MHz signal, and up to 8.7dB for the 1.8GHz at bit-error-rate of 10^-9, by optical carrier suppression.

Date Published: 5 October 2005
PDF: 6 pages
Proc. SPIE 5971, Photonic Applications in Nonlinear Optics, Nanophotonics, and Microwave Photonics, 597123 (5 October 2005); doi: 10.1117/12.628088

Published in SPIE Proceedings Vol. 5971:
Photonic Applications in Nonlinear Optics, Nanophotonics, and Microwave Photonics
Roberto A. Morandotti; Harry E. Ruda; Jianping Yao, Editor(s)