scholarly journals Optimal Combiners in Pre-Amplified Optical Wireless Systems under Medium-to-Strong Atmospheric Turbulence

2016 ◽  
Vol 21 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Nikos C. Sagias ◽  
Anthony C. Boucouvalas ◽  
Kostas Yiannopoulos ◽  
Murat Uysal ◽  
Zabih Ghassemlooy
Keyword(s):  
Optimal Design ◽  
Atmospheric Turbulence ◽  
Spontaneous Emission ◽  
Wireless Systems ◽  
Amplified Spontaneous Emission ◽  
Optical Wireless ◽  
Beat Noise ◽  
Maximal Ratio Combiner ◽  
Negative Exponential ◽  
Fading Environments

Abstract In this work we analytically investigate optimal combiners for pre-amplified diversity receivers that operate under medium-to-strong atmospheric turbulence. We first demonstrate that the combiner performance is strongly affected by the existence of a signal-amplified spontaneous emission beat noise at the output of the photodetector. Due to the signal-dependent nature of noise, the optimal combiner can be classified as a hybrid one, of which performance is between the well-known equal-gain and maximal-ratio combiner architectures. Having established the optimal design, we further assess the proposed combiner performance over gamma-gamma and negative-exponential fading environments.

scholarly journals Mitigation of turbulence-induced scintillation and ASE noise using aperture averaging based on hybrid DPPM and OOK modulation of FSO systems

2021 ◽  
Author(s):  
Ebrahim E. Elsayed
Keyword(s):  
Atmospheric Turbulence ◽  
Spontaneous Emission ◽  
Binary Data ◽  
Amplified Spontaneous Emission ◽  
Data Rate ◽  
Distribution Model ◽  
Aperture Averaging ◽  
Chernoff Bound ◽  
Digital Pulse ◽  
The Impact

Abstract The performance evaluation of free-space optical (FSO) communication using a digital pulse position modulation (DPPM) is investigated in this paper. The impact of atmospheric turbulence, scintillation and amplified spontaneous emission (ASE) noise has been taken into account. To reduce the turbulence-induced scintillation and optical power penalty, the use aperture averaging (AA) has been proposed in this paper. To evaluate the bit-error rate (BER) performance in the presence the atmospheric turbulence and amplified spontaneous emission (ASE), the use of the moment generation function (MGF) techniques are explained with the modified Chernoff bound (MCB) that is more accurate and an appropriate from Chernoff bound (CB). Such a system, which could provide a power efficient, a low cost, excessive flexibility and reliable or considered a massive solution in the bandwidth provision for future access networks, and together for higher data rate. The BER, are given for an optically preamplified DPPM FSO communication system impaired by pointing error (PE) and atmospheric turbulence combined, in addition to the ASE noise arising from the optical amplification. The gamma–gamma (GG) distribution model is used to characterize the whole range of turbulence conditions. The results reveal the superiority of DPPM with improved receiver sensitivity (at a binary data rate 2.5 Gbps and at typical FSO BER of 10 ^-9) of about 10 dB –11 dB for coding level (M) of 5 and optical link length (for turbulent interaction) of 2000 m more than an equivalent optically preamplified on-off keying non-return-to-zero (OOK-NRZ) approach, depending on the level of turbulence.

scholarly journals Improved bit error rate evaluation of M-ary DPPM modulation using an aperture averaging for FSO systems impaired by interchannel crosstalk and ASE noise

2021 ◽  
Author(s):  
Ebrahim E. Elsayed
Keyword(s):  
Atmospheric Turbulence ◽  
Spontaneous Emission ◽  
Bit Error Rate ◽  
Error Rate ◽  
Communication System ◽  
Amplified Spontaneous Emission ◽  
Data Rate ◽  
Aperture Averaging ◽  
Chernoff Bound ◽  
The Impact

Abstract The performance evaluation of free-space optical (FSO) communication system using the digital pulse position modulation (DPPM) and on-off keying non-return-to-zero (OOK-NRZ) approach are investigated in this paper. The impact of atmospheric turbulence, scintillation and amplified spontaneous emission (ASE) noise has been taken into account. To reduce the turbulence-induced scintillation and optical power penalty, the use aperture averaging has been proposed in this paper. To evaluate the bit-error rate (BER) performance in the presence the atmospheric turbulence and amplified spontaneous emission (ASE), the use of the moment generation function techniques are explained with the modified Chernoff bound that is more accurate and an appropriate from Chernoff bound. Such a system, which could provide a power efficient, a low cost, excessive flexibility and reliable or considered a massive solution in the bandwidth provision for future access networks, and together for higher data rate. The BER, are given for an optically preamplified DPPM FSO communication system impaired by pointing error and atmospheric turbulence combined, in addition to the ASE noise arising from the optical amplification. The gamma–gamma distribution model is used to characterize the whole range of turbulence conditions. The results reveal the superiority of DPPM with improved receiver sensitivity (at a binary data rate 2.5 Gbps and at typical FSO BER of 10-9) of about 10 dB – 11 dB for coding level (M) of 5 and optical link length (for turbulent interaction) of 2000 m more than an equivalent optically preamplified OOK-NRZ approach, depending on the leve of turbulence.

Effect of Molecular Morphology on Amplified Spontaneous Emission of Bis-Styrylbenzene Derivatives

2009 ◽  
Vol 21 (40) ◽  
pp. 4034-4038 ◽  
Author(s):  
Ryota Kabe ◽  
Hajime Nakanotani ◽  
Tomo Sakanoue ◽  
Masayuki Yahiro ◽  
Chihaya Adachi
Keyword(s):  
Spontaneous Emission ◽  
Amplified Spontaneous Emission ◽  
Molecular Morphology

scholarly journals Origin of Intramolecular Low‐Threshold Amplified Spontaneous Emission

2021 ◽  
pp. 2001956
Author(s):  
Qi Wei ◽  
Ruihong Duan ◽  
Qi Zhang ◽  
Linghai Xie ◽  
Ruidong Xia ◽  
...  
Keyword(s):  
Spontaneous Emission ◽  
Amplified Spontaneous Emission ◽  
Low Threshold

scholarly journals LACO-OFDM with Index Modulation for Optical Wireless Systems

2020 ◽  
pp. 1-1
Author(s):  
Ali Waqar Azim ◽  
Yannis Le Guennec ◽  
Marwa Chafii ◽  
Laurent Ros
Keyword(s):  
Wireless Systems ◽  
Optical Wireless ◽  
Index Modulation

Conformationally restricted 2,5-diphenyloxazoles: failure of the electromer model for anomalous amplified spontaneous emission spikes

2006 ◽  
Vol 104 (5-7) ◽  
pp. 957-969 ◽  
Author(s):  
J. Saltiel ◽  
R. A. Ivanov ◽  
D. A. Gormin ◽  
T. S. R. Krishna ◽  
R. J. Clark
Keyword(s):  
Spontaneous Emission ◽  
Amplified Spontaneous Emission ◽  
Conformationally Restricted
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