The maximum amount of power that an FSO system can

transmit is limited by the requirement to remain eye-safe.

That is, the system should not launch so much laser power

that it becomes hazardous to the human eye. This

requirement must be met regardless of the transmission

wavelength being used. However, different wavelengths

have different effects on the eye. Shorter wavelength 780-

850nm light, being closer to the visible part of the

spectrum, passes easily though the eye’s lens and is

focused onto the retina. Too much power causes damage

to the retina. 1550nm light, however, is largely absorbed by

the cornea and lens before it gets focused onto the retina.

Consequently, the power can be increased to 50 times

greater intensity before risking damage to the eye, as per

international eye-safety standards.

Higher power levels translate directly into longer ranges for FSO links, or similarly into greater

availability at the same range. The end result for a 1550nm system is a higher-performance system that

poses no safety hazard to the human eye.

Refer these links .

http://ieeexplore.ieee.org/document/948230/

http://www.fsona.com/tech/app_notes/fSONA_APPNOTE-Benefits_of_1550_for_Military.pdf

https://spie.org/Documents/Publications/00%20STEP%20Module%2008.pdf

MAM

The 980 nm products that are used in LASER offer operating power levels from 100 mW to 950 mW.Laser diodes can provide stable frequency and power operation over long ..

  Hai

1550nm diode lasers are now widely available that can operate at 2.5 Gbps, with devices capable of 10 Gbps operation also beginning to appear. By contrast, the highest data rate possible with commercial 785nm diode lasers is ~ 1 Gbps. Moreover, the wide availability of WDM components for 1550nm systems opens up a straightforward approach for scaling to higher throughputs, while using standard commercial components. Such components are not readily available for devices in the 780 to 850nm spectral range. Consequently, 1550nm technology paves the way for higher-bandwidth communication and the latest state-of-the-art in voice, video, and data applications for all phases of military operation.1550nm transmission is completely invisible to standard night-vision equipment, maintaining the maximum level of security on the battlefield and in foreign territory.