Saturation in wavelength-division multiplexing free-space optical communication systems

Abstract

The performance of a wavelength-division multiplexing (WDM) free-space optical (FSO) communication system in a turbulent atmosphere employing optical amplifiers to improve capacity is investigated, in the presence of amplified spontaneous emission noise, scintillation, beam spreading, atmospheric attenuation and interchannel crosstalk. Using on-off keying modulation, Monte Carlo simulation techniques are used to obtain the average bit error rate and system capability due to scintillation and the effect of introducing a power control algorithm (PCA) to the system is investigated. The PCA ensures that at any receiving instant, the same turbulence-free powers are received by all the receiving lenses. The performance of various WDM FSO communication system configurations such as non-amplified systems with an adaptive decision threshold (NOAADT), non-amplified systems with a non-adaptive decision threshold, fixed gain amplified systems with an adaptive decision threshold, fixed gain amplified systems with a non-adaptive decision threshold and saturated gain amplified systems with a non-adaptive decision threshold (SOANADT) are investigated. Results obtained show that the SOANADT is superior to the NOAADT and the PCA is only beneficial in amplified systems.

Keywords

wavelength-division multiplexing (WDM) / free-space optical (FSO) communication / crosstalk / optical amplifier (OA) / gain saturation / decision threshold

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Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature