Hi.

I would suggest you to look for the optisystem sample files. You can find the example “OFDM Modulator” in those sample folders. There is also another sample named “OFDM demodulator” that has the exact same implementation.
And as fas as theoretical aspect of the implementation is concerned i agree with karan ahuja that OFDM has the ability to transmit information with high data rates which has made it popular. OFDM has been used in many different applications in the RF domain
such as digital audio broadcasting (DAB), digital video broadcasting (DVB), and Wireless Local Area Networking (WLAN). OFDM was introduced to
optical domain in 2005, and has since been studied and investigated in two main techniques classified according to the detection scheme. The first technique is the direct detection optical OFDM (DDOFDM) and the second technique is the coherent optical OFDM (CO-OFDM). A direct detection optical OFDM aims for simpler transmitter or receiver than CO-OFDM for lower costs. DD-OFDM has an advantage that it is more immune to impulse clipping noise. Coherent Optical OFDM (COOFDM) is the next generation technology for optical communications since it integrates the advantages of both coherent systems and OFDM systems. COOFDM provides linear detection and high spectral efficiency. The CO-OFDM system has the ability to overcome many optical fiber restrictions such as Chromatic Dispersion (CD) and Polarization Mode Dispersion (PMD).

I hope this would help.
Thanks
Regards