Patent ID: 8718490
Filing Date: 2014-05-06
Classification: H04B,H04L

Abstract:
1. A method comprising: receiving an incoming light beam containing an optical OFDM signal carrying an optical carrier component, wherein data is fed to an electro-optical (EO) modulator sourced by a laser and the EO modulated output is filtered, amplified and sent over an optical fiber, wherein the optical carrier component from the incoming signal uses zero padding in OFDM modulation; producing an interference light beam between a received optical OFDM signal and an optical carrier extracted from the received optical OFDM signal to provide optical coherent detection of the received optical OFDM signal, wherein the incoming light beam and the interference light beam have one polarization state and have one central wavelength for homodyne detection, and optically splitting the received optical OFDM signal into a first part that is filtered with an optical filter to extract the carrier from the received optical OFDM signal and a second part similar to the received optical OFDM signal; and determining an error vector magnitude (EVM) as: where I Q Ĩ {tilde over (Q)}