Parameter optimization of gain-saturated semiconductor optical amplifiers for scintillation suppression in free-space optical links
Keywords:
semiconductor optical amplifier; free-space optical communication; atmospheric turbulence; scintillation suppression; gain saturation; parameter optimization; bit error; Gamma-Gamma turbulence modelAbstract
Atmospheric turbulence-induced scintillation remains a significant obstacle to reliable free-space optical (FSO) communication, causing random fluctuations in received signal intensity that degrade bit-error-rate performance and limit achievable link distances. While gain-saturated semiconductor optical amplifiers (SOAs) have shown promise as receiver-side mitigation devices, the optimal operating parameters for scintillation suppression have not been thoroughly characterized. This paper presents a comprehensive numerical study aimed at identifying optimal SOA parameters for reducing scintillation in FSO systems. We developed a rate-equation model of an SOA operating in the saturation regime and coupled it with a Gamma-Gamma turbulence channel model. Input scintillation was simulated for refractive index structure parameters (Cₙ²) spanning from 10⁻¹⁶ to 10⁻¹³ m⁻²/³. We systematically varied SOA bias current (50–200 mA), active region length (200–800 μm), and input coupling efficiency (0.5–0.9). Performance was evaluated using scintillation index reduction and bit-error-rate (BER) improvement as metrics. Our results demonstrate that optimal parameter combinations can achieve up to 6.2 dB reduction in scintillation index and decrease the power penalty required for BER = 10⁻³ from 8.5 dB to 3.1 dB under strong turbulence conditions (Cₙ² = 10⁻¹⁴ m⁻²/³). Bias current showed the most significant impact on performance, followed by active region length. Excess amplified spontaneous emission (ASE) noise constrained performance at elevated bias currents, defining an upper limit on usable saturation depth. These findings offer practical design guidelines for SOA-based FSO receivers and identify optimal operating regions for dependable link operation
References
N. J. Nzekwu, M. A. Fernandes, G. M. Fernandes, et al., "A comprehensive review of UAV-assisted FSO relay systems," Photonics, vol. 11, no. 3, p. 274, 2024.
M. A. Khalighi and M. Uysal, "Survey on free space optical communication: A communication theory perspective," IEEE Commun. Surveys Tuts., vol. 16, no. 4, pp. 2231–2258, 2014.
L. C. Andrews and R. L. Phillips, Laser Beam Propagation Through Random Media, 2nd ed. Bellingham, WA, USA: SPIE Press, 2005.
H. Kaushal and G. Kaddoum, "Optical communication in space: Challenges and mitigation techniques," IEEE Commun. Surveys Tuts., vol. 19, no. 1, pp. 57–96, 2017.
Z. Ghassemlooy, W. Popoola, and S. Rajbhandari, Optical Wireless Communications: System and Channel Modelling with MATLAB, 2nd ed. Boca Raton, FL, USA: CRC Press, 2019.
M. A. Esmail, H. Fathallah, and M. S. Alouini, "Outage probability analysis of FSO links over foggy channel," IEEE Photon. J., vol. 9, no. 2, pp. 1–12, 2017.
H. Tang, C. Yang, L. Qin, et al., "A review of high-power semiconductor optical amplifiers in the 1550 nm band," Sensors, vol. 23, no. 17, p. 7326, 2023.
M. Abtahi, P. Lemieux, W. Mathlouthi, and L. A. Rusch, "Suppression of turbulence-induced scintillation in free-space optical communication systems using saturated optical amplifiers," J. Lightw. Technol., vol. 24, no. 12, pp. 4966–4973, 2006.
K. Morito and S. Tanaka, "High-power semiconductor optical amplifier," in Proc. Opt. Fiber Commun. Conf., 2010, pp. 1–3.
Y.-Q. Hong, W.-H. Shin, and S.-K. Han, "Performance enhancement of gain saturated SOA based free space optical link using dual-wavelength transmission," Opt. Commun., vol. 446, pp. 134–140, 2019.
E. Desurvire, Erbium-Doped Fiber Amplifiers: Principles and Applications. New York, NY, USA: Wiley, 2002.
O. J. Bandele, P. Desai, M. S. Woolfson, and A. J. S. Phillips, "Saturation in cascaded optical amplifier free-space optical communication systems," IET Optoelectron., vol. 10, no. 3, pp. 71–79, 2016.
M. J. Connelly, "Wideband semiconductor optical amplifier steady-state numerical model," IEEE J. Quantum Electron., vol. 37, no. 3, pp. 439–447, 2001.
J.-L. Xiao and Y.-Z. Huang, "Numerical analysis of gain saturation, noise figure, and carrier distribution for quantum-dot semiconductor-optical amplifiers," IEEE J. Quantum Electron., vol. 44, no. 5–6, pp. 448–455, 2008.
A. V. Maslov and C. Z. Ning, "Modal gain, modal loss, and confinement factor in semiconductor lasers," IEEE J. Quantum Electron., vol. 40, no. 10, pp. 1389–1395, 2004.
P. S. Henry, "Lightwave primer," IEEE J. Quantum Electron., vol. 21, no. 12, pp. 1862–1879, 1985.
T. Kamalakis, T. Sphicopoulos, and D. Syvridis, "Analysis of the performance of semiconductor optical amplifiers in optical communication systems," J. Lightw. Technol., vol. 23, no. 3, pp. 1135–1145, 2005.
M. A. Al-Habash, L. C. Andrews, and R. L. Phillips, "Mathematical model for the irradiance probability density function of a laser beam propagating through turbulent media," Opt. Eng., vol. 40, no. 8, pp. 1554–1562, 2001.
G. P. Agrawal and N. K. Dutta, Semiconductor Lasers, 2nd ed. New York, NY, USA: Van Nostrand Reinhold, 1993.
L. A. Coldren and S. W. Corzine, Diode Lasers and Photonic Integrated Circuits. New York, NY, USA: Wiley, 1995.
D. M. Baney, P. Gallion, and R. S. Tucker, "Theory and measurement techniques for the noise figure of optical amplifiers," Opt. Fiber Technol., vol. 6, no. 2, pp. 122–154, 2000.
W. Mathlouthi, P. Lemieux, M. Salsi, et al., "Fast and efficient dynamic model of semiconductor optical amplifiers," J. Lightw. Technol., vol. 26, no. 12, pp. 1673–1681, 2008.
S. M. R. Motaghian Nezam, Y. W. Lee, and A. E. Willner, "Theoretical and experimental analysis of the impact of SOA gain saturation on optical signal-to-noise ratio," J. Lightw. Technol., vol. 21, no. 12, pp. 3263–3271, 2003.
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