Free Space Optical Communications — Theory and Practices

2015 International Conference on Communications and Signal Processing (ICCSP), 2015

Now a days the wireless technology has become popular in the wireless system. FSO is a technology that uses the visible to near infrared (NIR) light propagating through the atmosphere to transmit information. FSO communications are attracting attention as the contemporary engineering science to resolve the last mile bottleneck issues in local area access networks due to their high bandwidth, low cost implementation in a non-licensed spectrum, relatively low power using up and security compared with RF technologies. Equally we know that the free space optical communication is extremely impressed by the various atmospheric conditions which cause the degradation of the carrying out of FSO link. This report introduces the study of the issue of the various atmospheric conditions on the FSO link. This report includes the result of the fog by analysis the various fog models such as Kim Model, Kruse Model. And also analysis the wet and dry snow over the FSO links.

Free-space optical communication (FSO) is a revolutionary technology that utilizes optical signals to transmit data wirelessly, providing a viable alternative to conventional wired systems. This paper aims to explore the FSO system, analyze previous research, and discuss the challenges associated with information transmission in FSO networks, particularly under adverse weather conditions that can lead to weakened signals. FSO technology has garnered significant attention due to its numerous advantages, such as high data rates, quick installation, cost-effectiveness, and enhanced security. Many researchers have delved into this field, contributing valuable insights and advancements in the FSO domain. However, one of the major challenges faced by FSO systems is their sensitivity to weather conditions in the vicinity of the transmitter site. Adverse weather factors, such as rain, fog, snow, and dust, can attenuate the optical signals, leading to a reduction in signal strength and potentially affecting data transmission reliability.

2014

Free Space Optics (FSO) is a promising solution for very high data rate point-to- point communication. Recently, it has received significant attention as a possible alternative to overcome the bottleneck connectivity problem and as a supplement to more conventional RF/microwave links. FSO communications has become attractive for a number of reasons including unlicensed spectrum and a narrow beam width. Moreover, FSO becomes the best solution to solve the problems occurred in conventional wireless system by using optical fiber because it uses laser light to transmit data between two points. The FSO uses beam of light to provide optical connection that can send and receive video, voice, and data information. In this paper Free Space Optical communication concept will be introduced. In addition, the performance of FSO communication link will analysis and illustrates its main challenges and it possible solutions.

Gbps of text, speech(sound), images and video graphic communications through the air as medium, allowing exchange of data without any use of conventional fiber optic cables or securing frequency spectrum licenses. FSO system could carry full duplex (bi-directional) data at giga bits per second rates over Metropolitan distances of a few city blocks, buildings or area of few kms. FSO, also known as wireless optics, which overcomes this last-mile access blockage by sending high -bit rate signals through the air using laser transmission.

International Journal of Engineering Research and Technology (IJERT), 2015

https://www.ijert.org/literature-survey-and-issue-on-free-space-optical-communication-system https://www.ijert.org/research/literature-survey-and-issue-on-free-space-optical-communication-system-IJERTV4IS020527.pdf Present communication era demand a communication link with high bandwidth, maximum performance, minimum errors and good channel capacity. All these can be well achieved by using free space optical communication system. Because FSO system does not require any license for its establishment and the working. Now this paper consists of detailed survey of FSO system, its advantages, disadvantages and different applications. In FSO system no. of modulation techniques used to modulate information signal at source side like: AM, FM, IM, OOK etc. each FSO system uses a high-power optical transmitter for transmit source signal towards destination and receiving side high sensitivity receiver used. But the atmospheric attenuation is major challenge for faced by FSO systems which affect the performance of the link. The other factors which can affect the FSO are humidity, water vapour, signals absorption, smoke, beam scintillation, spreading and wandering are some of the factors.

IEEE Access

The next generation (NG) optical technologies will unveil certain unique features, namely ultra-high data rate, broadband multiple services, scalable bandwidth, and flexible communications for manifold end-users. Among the optical technologies, free space optical (FSO) technology is a key element to achieve free space data transmission according to the requirements of the future technologies, which is due to its cost effective, easy deployment, high bandwidth enabler, and high secured. In this article, we give the overview of the recent progress on FSO technology and the factors that will lead the technology towards ubiquitous application. As part of the review, we provided fundamental concepts across all types of FSO system, including system architecture comprising of single beam and multiple beams. The review is further expanded into the investigation of rain and haze effects toward FSO signal propagation. The final objective that we cover is the scalability of an FSO network via the implementations of hybrid multi-beam FSO system with wavelength division multiplexing (WDM) technology.

Ijca Proceedings on International Conference and Workshop on Emerging Trends in Technology 2014, 2013

Free Space Optical (FSO) Communication is preferred over the radio frequency communication and microwave systems for about three decades. Next generation FSO communication systems use fiber-optic technology for unseamed and better data propagation rates. Besides license-free long-range operations, it has many other advantages like high bandwidth, small size, cheap and easy installation [1]. However, atmospheric turbulence highly influences the optical waves. As a result, it has few limitations like scintillation, dispersion of beam, etc. . Such challenges are overcome by using different mediums and wavelengths. This paper considers the wavelength of 1550 nm with PRBS generator at bit rate 1.25 Gb/s using both LASER and LED. These two optical sources are then compared on the grounds of Q-factor, Bit Error Rate (BER), wavelength spectrum and eye diagrams for the analysis of the sources that can be used in the FSO systems.

Free space optical (FSO) communication is an upgraded supplement to existing wireless technologies. FSO technology leads vast modulation bandwidth, unlicensed spectrum, cost effective deployment, quick redeploy and much more. FSO systems are used to transmit and receive all kind of data at high data rates (up to 100 Gbps). Today researchers are preliminary focused to use the free space communication systems to make their inter satellites links. This paper gives a review on the laser diodes, modulation schemes and the detection techniques which are deployed in the FSO systems.

Over the last two decades free-space optical communication (FSO) has become more and more interesting as an adjunct or alternative to radio frequency communication. Free-space optical (FSO) communication links are most susceptible to a tremendous amount of variability and offer a real challenge for efficient, robust system design.one method of transmitting information from one place to another by sending pulses of light through an optical fiber is Fiber-optic communication , FSO communication systems will provide a large dynamic range of performance through most cases .It is a line-of-sight (LOS) technology that transmits a modulated beam of visible or infrared light through the atmosphere for broadband communications. In a way similar to fiber optical communications, free space optics uses a light emitting diode (LED) or laser (light amplification by stimulated emission of radiation) as a point source for data transmission. However, in free space optics, an energy beam is collimate...

IOSR Journal of Electrical and Electronics Engineering, 2014

Free space optics is a line-of-sight technology, which uses LASERS and Photo detectors to provide optical connections between two points—without the fiber. Increased needs for bandwidth require technology that goes beyond traditional copper lines. The technology advancement in internet scales faster than Moore's law which makes it infeasible to dig installed lines in metropolitan areas; the industry now realized the benefits of free space optical communication. Free-space optical (FSO) communication links are attractive because they provide a means of low cost, high bandwidth, reduced time-to-market, secure and are a reliable means of communications. This paper describes the benefits of FSO along with operation of such links working outdoors in an open atmosphere under various effecting field parameters such as atmospheric attenuation, beam divergence and scintillation where the performance of FSO link is evaluated in terms of transmitted and received power.