A synchronized signaling insertion and detection scheme for reconfigurable optical OFDM access networks

A simple low-cost, synchronized, in-band, and stable signaling insertion and detection scheme is proposed for the reconfigurable wavelength division multiplexing and orthogonal frequency division multiplexing (WDM-OFDM) access network. The low-frequency signaling is generated with the optical OFDM signal. Such signaling data can be simply detected by using a low-speed photon diode cascaded with an electrical low-pass filter. The low-frequency insertion and detection (LFID) induced impairments are analyzed theoretically and verified through experiments. The principle to design LFID is derived and the optimization of such a scheme is discussed. The LFID scheme is demonstrated for a reconfigurable WDM-OFDM optical network with 15 Gb/s per wavelength. The power penalty of signaling after 12.5 and 100 km is 0.35 and 0.85 dB at bit error rate (BER) of 3.44 × 10-8, respectively. The ON-OFF keying insertion induced power penalty for BER at 2.4 × 10-4 is 0.9 dB for back-to-back, 1.1 dB for 12.5 km, 1.5 dB for 100 km, respectively. There is only 0.6 dB additional penalty caused by the transmission fiber of 100 km, which demonstrates that this signaling scheme does not increase system penalty considerably.