9 Tight mechanical tolerancing in the optomechanical assembly design can help prevent movement of internal lens elements, which in turn improves pointing accuracy. 8 Pointing accuracy requirements may typically be on the order of several hundred µrad, so extra gimbals or other steering mechanisms may be needed. The narrow beam divergence inherent to laser-based communication (about 10X less than RF signals) makes pointing accuracy more important for FSO compared to traditional RF communications. The pointing accuracy and stability of the optical systems used for FSO are also critical. (0.5-10μ size: 1 mg/m 3 visability: ~0.5 km)įigure 3: Table showing the attenuation of FSO communications in different weather conditions such as fog and rain. Scintillation refers to rapid variations in the received signal because of the structure of the atmosphere through which the light propagates. Optical systems designed to receive FSO signals must be highly-sensitive, as atmospheric absorption, dispersion, the large distances between the transmitter and receiver, and scintillation make the ratio between the outgoing and incoming signal very large ( Figure 3). Considerations for Optical Components Used in FSO This facilitates fast, high-bandwidth, secure communication that can save lives. 4 The receivers for FSO communication can also be designed to be mobile and easy to use, allowing them to be easily deployed in the field for defense applications. FSO laser transmissions can be encrypted, are invisible or narrow-band, cannot be deciphered using RF meters or spectrum analyzers, propagate along a line-of-sight path which is difficult to intercept, and a matching FSO receiver is needed to collect the information. Secure FSO Communication for DefenseįSO communication is highly-advantageous for defense applications because of its increased level of security compared to RF or other wireless communication. 5įigure 2: Networks of satellites have already been deployed to facilitate high-speed, free-space optical communication to ground-based receivers. FSO communication offers a practical solution for creating global, broadband wireless connectivity. 4 Many different companies are establishing networks of satellites that will facilitate high-speed, FSO-enabled communications ( Figure 2). In some cases, it is also cheaper to use FSO communication from one location on the ground to another than to install optical fiber cables.Ĭurrent commercially-available FSO networks feature typical data rates ranging from 100 Mbps to 10 Gbps, while high-end prototypes report capacities as high as 160 Gbps. 3 The costs associated with setting up ground-based radio stations to receive FSO signals are also significantly less than installing new optical fiber connections because of the associated labor and digging costs. Optical communication provides bandwidth increases of 10 – 100X compared to radio frequency (RF) wireless communication and requires less input power. FSO communication offers the potential for better wireless communication for groups that already have broadband internet access, as well as those that do not. 1 "Broadband" here is defined as internet faster than dial-up. The World Bank estimates that 80% of the population of advanced economies have broadband high-speed internet access, while only 35% of the population in developing countries have broadband access. High-Speed Internet: A Modern Basic Necessity 2 In addition to fast internet access that can reach areas without optical fiber connections, FSO provides the means for highly-secure communications for defense applications that are difficult to intercept.įigure 1: General process for free-space optical communication. According to Global Market Insights, the FSO market will likely grow at a rate of over 35% in each of the next five years, skyrocketing from $200 million to $2 billion by 2027. Free-space optical (FSO) communication involves using lasers to transmit data from one location to another, whether it is from a satellite to a telescope-like ground station, one satellite to another, or between different locations on the ground ( Figure 1). 1 It opens up opportunities for education, employment, healthcare access, and government transparency and accountability that would be otherwise lost. The World Bank has declared that broadband internet access is a basic necessity for economic and human development, not a luxury. Enables fast, affordable internet that can reach rural areas or disaster sitesĮnables highly-secure communication for defense applicationsįast, global communication is critical in our increasingly-connected world.
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