Abstract:
Electroabsorption modulator (EAM) based relay is employed for the transmission
of differential phase shift keying (DPSK) and on-off keying (OOK) signals over
a free space optical (FSO) communication link. The FSO link is based upon the
Gamma-Gamma (Γ-Γ) channel model and we have considered both medium and
strong atmospheric turbulence conditions for analysis purpose. DPSK and OOK
modulated signals at a data rate of 10 Gbps are transmitted over the FSO link
by employing all-optical amplify and forward (AOAF) and all-optical regenerate
and forward (AORF) relay assisted techniques. The BER results are analyzed
with respect to received optical power (ROP) in the proposed model. In the fol lowing simulations, it has been shown that AORF relay-assisted OOK is better
than AOAF at high data rates under medium atmospheric turbulence. Whereas,
for DPSK modulated signals the performance is almost the same for both AORF
and AOAF relay based links. The AORF based relay for transmission of OOK
and DPSK modulated signals show significant improvement under strong atmo spheric turbulence compared to the AOAF based relay link. Furthermore, under
multiple relay scenario for DPSK signal, AOAF results degraded while AORF
remains almost the same under strong atmospheric turbulence.
