A new beat interference cancellation receiver with 3×3 optical coupler for the SSB-OOFDM signal with reduced guard band

In this paper, we present a new method to implement beat interference cancellation receiver (BICR) for single-sideband optical orthogonal frequency division multiplexing (SSB-OOFDM) signal, which improves the spectral efficiency (SE) by reducing the guard band (GB) between the optical carrier and the OOFDM signal while mitigating the impact of signal-signal beat interference (SSBI). This BICR structure is relatively simple using only an optical interleaver (IL), a 3×3 optical coupler (OC) and three photodiodes (PDs). A system simulation for the 40 Gbit/s 16-QAM SSB-OOFDM signal with the reduced GB is carried out to prove the feasibility of this new scheme. The simulation results show that our proposed BICR has a better performance to suppress SSBI and a higher SE than the conventional direct-detection receiver (CDDR) according to the EVMs and the constellations.