CHANNEL ANALYSIS OF OPTICAL SINGLE SIDEBAND QUADRATURE PHASE SHIFT KEYING WITH SUBCARRIER RADIO SIGNAL FOR LASER SATELLITE COMMUNICATIONS UNDER ATMOSPHERIC TURBULENCE

Abstract

Compared to traditional satellite radio communication, laser communication techniques
demonstrate greater performance in terms of available data rates, and also guarantee a reduction
in size, weight and power of the communication subsystem. In a satellite laser communication
system, a laser source generates a narrow beam of radiation at the transmitter. A laser beam
propagating through the atmosphere towards an optical receiver can experience large random
fluctuations in optical intensity due to turbulence, which can lead to loss of power in the receiver
and degrade system performance. In a subcarrier multiplexing (SCM) system, multiple information
is electrically modulated at different radio carrier frequencies. Analog or digital signals carrying
information may have different modulation formats. Optical single sideband radiation (OSSB) is
typically generated using a dual drive Mach–Zehnder modulator (MZM). In the article, the analysis
channel for optical single-sideband quadrature phase-shift keying transmitted signal was proposed
for different distances under atmospheric turbulence conditions. The numerical results of
laser satellite communications are based on an atmospheric altitude model of the structural characteristic
of Hufnagel-Valley (H-V) refractive index fluctuations. The performance analysis makes
it possible to estimate the effect of atmospheric turbulence, pointing error, and the diameter of the
received aperture on the received power during transmission of a laser signal between a ground
station and a satellite for a laser communication system, where the optical wave is a collimated
beam with a wavelength of 1550 nm.