Wireless optical transmission of fast ethernet, FDDI, ATM, and ESCON protocol data using the TerraLink laser communication system

The TerraLink laser communication (lasercom) system was developed as a cost -effective, high-bandwidth, wireless alternative to fiber optic transmissio n. The advantages of lasercom over fiber optic cabling are primarily econom ic. However, free-space lasercom is subject to atmospheric effects, such as attenuation and scintillation, which can reduce link availability and may introduce burst errors not seen in fiber transmission. The TerraLink transc eivers use large receive apertures and multiple transmit beams to reduce th e effects of scintillation. By designing the lasercom link with sufficient margin for atmospheric attenuation and scintillation, a bit error rate (BER ) of 10(-9) or better can be achieved. Since we designed the TerraLink tran sceivers to be eye-safe at the transmit aperture, each system is range-limi ted. Link power budgets for the TerraLink systems are presented, and link m argin data are shown that quantitatively describe how the effective laser l ink range varies in different weather conditions. Since the TerraLink trans ceivers act as simple repeaters, they are protocol-independent. Examples of TerraLink installations transmitting wireless fast ethernet (125 Mbits/s), fiber distributed data interface (FDDI) (125 Mbits/s), asynchronous transf er mode (ATM) (155 and 622 Mbits/s), and Enterprise Systems Connection (ESC ON) (200 Mbits/s) protocol data are presented. (C) 1998 Society of Photo-Op tical Instrumentation Engineers. [S0091-3286(98)00812-5].