Performance of Signal Transmission via Subcarrier Multiplexing with 4-ASK over Low-Frequency Passbands of Multimode Fibers

摘要

Transmitting a high data rate signal over multimode fibers, it has been shown that using the low-frequency passbands along with the 3-dB modal bandwidth of multimode fibers can be done via the technique called Subcarrier Multiplexing. However, there is a problem from utilizing the passbands of multimode fibers; that is, they are frequency-selective; resulting in a significant attenuation if some subcarriers are located at the nulls. In this paper, instead of using just the on-off keying (OOK) in transmitting each subcarrier signals over each sub-channel, 4-ASK is adopted for transmitting the subcarrier signal over the 3-dB modal channel to improve the performance of the whole system. It is found that, without any error-correcting codes applied, a signal with a data rate of 600 Mbps can be successfully transmitted over a 1-km multimode fiber with a BER of lower than 10⁻⁷. Furthermore, a very low BER of 10⁻⁹ can be obtained with a signal with a data rate of 500 Mbps.