[caption id="attachment_3076" align="alignleft" width="300"] Real-time 64-QAM-encoded OOFDM signal spectra at the output of the VCSEL intensity modulator with equal power loading and adaptive power loading using High Resolution Optical Spectrum Analyser.[/caption]

This paper shows the contribution of the Apex Technologies High Resolution Optical Spectrum Anlyser in evaluating  low-cost, un-cooled vertical cavity surface-emitting lasers (VCSELs) as intensity modulators in real-time optical OFDM (OOFDM) transceivers.  64-QAM-encoded OOFDM signal spectra at the output of the VCSEL intensity modulator with equal power loading and adaptive power loading are compared using High Resolution Optical Spectrum Analysers AP2040/AP2050 series. End-to-end real-time transmission of 11.25Gb/s 64-QAM-encoded OOFDM signals over simple intensity modulation and direct detection, 25km SSMF PON systems is experimentally demonstrated with a power penalty of 0.5dB. The low extinction ratio of the VCSEL intensity-modulated OOFDM signal is identified to be the dominant factor determining the maximum obtainable transmission performance. This work is of great value as it demonstrates the possibility of future mass production of cost-effective OOFDM transceivers for PON applications.