Atmospheric propagation characteristics of highest importance to commercial free space optics

Korevaar, Eric J.; Kim, Isaac I.; McArthur, Bruce

doi:10.1117/12.483804

Cited by 28 publications

(20 citation statements)

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“…The transmitter and receiver optics efficiencies η T and η R are scaling factors for the received optical power. The nominal values for the normalized beam width and the normalized jitter standard deviation are w z /a = 25 and σ s /a = 3, respectively [28] and are presented in Table III.…”

Section: A Weather and System Parametersmentioning

confidence: 99%

“…Experimental measurements show that C 2 n varies from 10 −15 to 2 × 10 −13 as the turbulence strength varies from weak to strong conditions, and the attenuation factor is empirically expressed in terms of visibility [22]. Table II summarizes The parameters of the system under investigation are presented in Table III [24], [28]. Typical values for receiver sensitivity S v and noise standard deviation σ n are taken from a commercial transimpedance amplifier [29].…”

Section: A Weather and System Parametersmentioning

confidence: 99%

See 1 more Smart Citation

Outage Capacity Optimization for Free-Space Optical Links With Pointing Errors

Farid

Hranilovic

2007

J. Lightwave Technol.

1,292

927

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Abstract-We investigate the performance and design of free-space optical (FSO) communication links over slow fading channels from an information theory perspective. A statistical model for the optical intensity fluctuation at the receiver due to the combined effects of atmospheric turbulence and pointing errors is derived. Unlike earlier work, our model considers the effect of beam width, detector size, and jitter variance explicitly. Expressions for the outage probability are derived for a variety of atmospheric conditions. For given weather and misalignment conditions, the beam width is optimized to maximize the channel capacity subject to outage. Large gains in achievable rate are realized versus using a nominal beam width. In light fog, by optimizing the beam width, the achievable rate is increased by 80% over the nominal beam width at an outage probability of 10 −5 . Well-known error control codes are then applied to the channel and shown to realize much of the achievable gains.Index Terms-Atmospheric turbulence, beam misalignment, free-space optical (FSO) communications, optical channel capacity, outage probability, pointing errors.

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Section: A Weather and System Parametersmentioning

confidence: 99%

Section: A Weather and System Parametersmentioning

confidence: 99%

Outage Capacity Optimization for Free-Space Optical Links With Pointing Errors

Farid

Hranilovic

2007

J. Lightwave Technol.

1,292

927

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show abstract

“…E.g. in [11] the dependency of required link margin on propagation distance is empirically found to be approximately linear. This finding deviates strongly from the results given above, however [11] gives no definition of required link margin.…”

Section: '6and86621 $1' And21and/86216mentioning

confidence: 97%

Scintillation loss in free-space optic IM/DD systems

David¹

2004

Free-Space Laser Communication Technologies XVI

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%675$&7When designing free-space optics systems, one key issue is to assess the impact of scintillations and to find an appropriate link margin to cope with atmospheric fading. Huge effort is spent to find mathematical models to describe laser beam propagation through the atmosphere. However, these models are quite cumbersome to use for the communications engineer. On the other hand, there are empirical models that try to describe the influence of scintillations and other system parameters in a simple and easy to use manner. Nevertheless, they are empirical and not based on theory. This paper is intended to close the gap between mathematical theory and empirical models.Therefore, a simple yet accurate receiver model is introduced. Based on turbulence theory and using the recently proposed convolution method assuming independent sub-aperture intensities, probability distributions of the received power are derived. Aperture averaging as well as multiple transmitter systems can be described this way. Power penalties are found by numerically calculating the resulting bit error probabilities for varying mean values of received power. Finally a model for appropriate link margins under different atmospheric conditions, taking transmitter diversity and aperture averaging into account, is derived and compared to empirical models..H\ZRUGV FSO, scintillations, scintillation loss, receiver model ,1752'8&7,21Optical free-space communications systems greatly suffer from intensity fluctuations (scintillations) at the receive aperture due to atmospheric turbulence. Varying optical input power to the receiver leads to varying bit error probabilities. Deep fades with respectively high bit error probabilities may significantly deteriorate the over-all system performance. Scintillation effects are mitigated by use of multiple transmit and/or receive apertures and by relying on aperture averaging over large receive apertures. To determine the system performance two basic things have to be known: the probability density function (PDF) of received power and a receiver model giving a relation between received power and bit error probability. Whereas the latter one depends on the characteristics of the receiver circuitry, the former is influenced by a number of system and atmospheric parameters: The link distance L, the accumulated number N of transmit and receive apertures, the diameter of the receive aperture(s), the according aperture averaging factor and finally the turbulence strength conveniently expressed through the parameter C n 2 . The necessary PDF of received power can be derived from arbitrary models of intensity PDF by using the convolution method as described in [1]. For the weak fluctuation regime a lognormal distribution can be assumed for the intensity fluctuations.In the following we derive a receiver model valid for IM/DD schemes using PIN or APD photo diodes. Subsequently we review the weak fluctuation theory and explain the convolution method for deriving receive power distributions. Finally we assess the bit error ...

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“…In 1970, Nippon Electric Company (NEC) of Japan demonstrated the first full duplex FSO link by using 632.8 nm He-Ne laser to compensate the traffic data up to a length of 14 km between the Yokohama and Tamagawa [13]. Several experiments from the last decade further stimulated researchers in the field of FSO [14][15][16][17][18][19][20][21]. The link equation for FSO is given by the following equation [22]:…”

Section: Fso For Terrestrial Communicationmentioning

confidence: 99%

The Role and Challenges of Free-space Optical Systems

Chaudhary¹,

Amphawan²

2014

Journal of Optical Communications

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Abstract:Complementing wireless radio networks with free-space optics (FSO) achieves high data rates by modulating radio subcarriers over an optical carrier without expensive optical fiber cabling, enabling a pervasive platform for reaching underserved areas. In this paper, we review the main features of FSO for terrestrial and inter-satellite communications. Simulations of 1 Gbps data transmission through FSO links in both terrestrial and inter-satellite communications have been investigated to highlight potential atmospheric challenges in FSO.

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Atmospheric propagation characteristics of highest importance to commercial free space optics

Cited by 28 publications

References 0 publications

Outage Capacity Optimization for Free-Space Optical Links With Pointing Errors

Outage Capacity Optimization for Free-Space Optical Links With Pointing Errors

Scintillation loss in free-space optic IM/DD systems

The Role and Challenges of Free-space Optical Systems

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