Single mode fiber-free space optic based hybrid $$32\times 2~\text{Gbps}$$ WDM-PON architecture employing optical frequency comb source and polarization multiplexing

Abstract

In this paper, we propose a cost-efficient single mode fiber-free space optics (SMF-FSO) based hybrid $$32 \times 2~\text{Gbps}$$ wavelength division multiplexed passive optical network (WDM-PON) employing optical frequency comb (OFC) source and polarization multiplexing. OFC source is realized at optical line terminal (OLT) by modulating a single continuous wave (CW) laser source with radio frequency (RF) sinusoidal signal and dual-drive Mach–Zehnder modulator (DD-MZM). 16 coherent optical carriers are used to split into 32 x and y-orthogonal polarization states which are used to transmit the on-off keying (OOK) data of 32 channels to remotely located optical network units (ONUs). The performance of the channels is analyzed with bit error rate (BER) plots employing Gamma–Gamma (GG) FSO channel model at different turbulence regimes and lengths of FSO link. Moreover, the effect of varying the polarization mode dispersion (PMD) on BER is also evaluated. The cost of the proposed architecture is analyzed and compared with conventional PON architecture. The cost efficiency of the proposed architecture is demonstrated by the use of a single CW laser source to transmit the data of 32 users between remote node (RN) and ONUs through FSO links having reduced installation and maintenance costs.