Photonic frequency-upconversion efficiencies in semiconductor optical amplifiers

We investigated the characteristics of the photonic frequency-upconversion process in semiconductor optical amplifiers. We derived a simple analytical expression for the upconversion efficiency, and investigated its dependence on various parameters. We experimentally confirmed our results.

I. Introduction

THE Radio-on-Fiber technology has recently attracted much attention for broad-band radio access system applications [1]– [5]. Fig. 1. Experimental setup for all-optical frequency-upconversion using SOA. TLS: tunable light source. ML: master laser. SL: slave laser. OC: optical circulator. In the experiment, GHz and GHz. For the increase of the total data traffic capacity, linking radio-on-fiber systems to the existing wavelength-division-multiplexing (WDM) networks is an important issue. For this, several schemes have been demonstrated using either Mach–Zehnder modulators (MZMs) [3], [4] or nonlinear photodetection of photodiodes (PDs) [5], where WDM data signals at different wavelengths are frequency-upconverted to the desired millimeter-wave frequencies. In addition, we have proposed and experimentally demonstrated an efficient photonic frequency-upconversion scheme using cross-gain modulation in a semiconductor optical amplifier (SOA) [6].