Research on Adaptive Modulation Algorithm of Multimode Fiber Communication System Using Coherent Optical OFDM

Coherent Optical OFDM (CO-OFDM) technology can take full advantage of the high frequency band-pass regions of the multimode fiber, and carry high-speed and high capacity communication. However, the deep fading in high frequency band pass region of the multimode fiber will affect the system performance. We propose an adaptive modulation algorithm using threshold allocation of optical signal to noise ratio (OSNR), and introduce the CO-OFDM multimode fiber communication systems based on adaptive modulation (AM). The experimental results show that AM-CO-OFDM reduces 2dB OSNR than that without AM technology in 21.4Gb/s, 200km multimode fiber CO-OFDM transmission system.