30-Gb/s Bidirectional Transparent Optical Transmission With an MMF Access and an Indoor Optical Wireless Link

This letter describes a 30-Gb/s bidirectional transparent optical transmission, over a 4.4-km multimode fiber (MMF) in combination with an indoor optical wireless (OW) link, which could provide limited mobility. Due to MMF's advantages, such as lower installation costs and easy maintenance, it is used as the access link. To enhance the MMFs bandwidth and provide the feasibility to use standard single-mode devices in the OW terminal (OWT), center launching and center detection techniques are both utilized. The stability of the indoor OW channel and the modal noise in MMF are investigated. Discrete multitone modulation with power and bit loading algorithms are applied to improve system's frequency utilization efficiency and robustness.