Abstract
This work investigates the propagation of modulated optical signals under controlled turbulence conditions. Atmospheric
channel are emulated in a laboratory testbed, where turbulence is characterized by varying the wind pressure and
temperature inside the chamber. The observed turbulence index structure parameter (
) lies in the range of
to , which indicates the Gamma-Gamma ( ) channel model. It is observed that the turbulence strength is increased
inside the chamber as temperature increases,and increase in the wind pressure leads to variation in
values.Thesystem
performance is compared by employing various modulation schemes namely amplitude shift keying (ASK), frequency shift
keying (FSK), and binary phase shift keying (BPSK) under turbulence. A 10 meter single input single output (SISO) optical
link is used to observe the performance metrics ofsignal-to-noise ratio (SNR), bit error rate (BER), and outage probability. It
is found that the system indicates the better performance for BPSK modulation. The higher SNR values range (from 7.26
dB to 8.82 dB) is obtained for BPSK, followed by the performance of FSK and ASK. A minimum average outage is observed
for BPSK which is comparable to ASK, however, the latter requires a slightly higher SNR to achieve the same outage
probability.
Keywords
Free Space Optics (FSO), Atmospheric Turbulence, Modulations formats.
Citation
GIREESH G. SONI, ABHISHEK TRIPATHI, MANASWI SHROTI, KUSHAGRA AGARWAL, RAMCHANDRA GURJAR, Comparative analysis of FSO links with various modulation formats under controlled turbulence, Optoelectronics and Advanced Materials - Rapid Communications, 17, 9-10, September-October 2023, pp.442-445 (2023).
Submitted at: March 20, 2023
Accepted at: Oct. 9, 2023