Frequency offset estimation algorithm for a multi-subcarrier coherent fiber optical system

We introduce a new technique for obtaining the frequency offset introduced at the receiver due to the heterodyning of the transmitter laser and the local oscillator. This technique is needed for multi-subcarrier systems, as the offset must be removed without knowledge of the modulation format, making well-known algorithms that correct using it impractical. By detecting the spectral edges for the transmitted and received signals, it is possible …