Bit and power loading for optical IM/DD transmission

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is an established technique for equalization of the dispersion-dominated fiber-optical channel. The dispersive nature of the optical channel results in a frequency selective equivalent channel if double sideband (DSB) intensity modulation (IM) and direct detection (DD) is employed. In order to maintain the allpass nature of the physical channel, sideband suppression using optical filters has to be applied. We will show that by use of bit and power loading, this optical filter can be rendered unnecessary.