Patent ID: 8027589

Claim:
An all-optical frequency upconversion method to generate a single optical radio frequency (RF) signal in a radio-over-fiber system, which uses a semiconductor optical amplifier and an optical filter, the all-optical frequency upconversion method comprising: mixing an optical intermediate frequency signal with an optical local oscillation signal utilizing a four wave mixing effect in the semiconductor optical amplifier; filtering the optical RF signal from number of frequency component signals generated through the four wave mixing effect in the semiconductor optical amplifier by using the optical filter to extract the optical RF signal; transmitting the optical RF signal to a remote antenna station through a first optical fiber; and converting the optical RF signal transmitted through the first optical fiber using a photodetector in the remote antenna station to generate electrical RF signals, wherein a laser signal having an optical frequency of v IF is modulated by an electrical frequency of f IF to generate the optical intermediate frequency signal, and a laser signal having an optical frequency of v LO is modulated by an electrical frequency of f LO to generate the optical local oscillation signal, and wherein the electrical RF signals have electrical frequencies of f LO +f f IF and f LO −f IF .