In optical line terminal OLT, quadrature amplitude modulation QAM intensity modulated OFDM signal with x polarization at 10 Gbit/s is transmitted as downstream. At each ONU, matlab programming optical OFDM signal is demodulated with direct detection, and polarization signal is modulated for upstream on off keying OOK data at 5 Gbit/s. Simulation results show that matlab programming power penalty is negligible for both optical OFDM downstream and matlab programming on off keying upstream signals after over 50 km single mode fiber SMF transmission. Abatement of PAPR for ACO OFDM deployed in VLC techniques by frequency modulation of matlab programming baseband signal forming matlab fixed envelopeTo inhibit matlab programming effect of non linearity of matlab programming LEDs ultimate to matlab huge increase in matlab programming peak to average power ratio PAPR of matlab programming OFDM alerts in matlab programming Visible light conversation VLC we suggest matlab frequency modulated constant envelope OFDM FM CE OFDM technique. The abrupt amplitude adaptations in matlab programming OFDM signal are frequency modulated before being applied to matlab programming LED for electro optical conversion leading to matlab fixed envelope signal. The LED is maintained in matlab programming linear region of operation by this constant envelope signal at sufficient DC bias.