Evolution of Fiber Optic System

First Generation

. The first generation of lightwave systems uses GaAs semiconductor laser and operating region was near 0.8 µm. Other specification of this generation are as under :

i) Bit rate                                        : 45 Mb/s

ii) Repeater Spacing                      : 10 km

Second Generation

i) Bit rate                                        : 100 Mb/s to 1.7 Gb/s

ii) Repeater spacing                       : 50 km

iii) Operating wavelength               : 1.3 µm

iv) Semiconductor            : In GaAsP

Third Generation

i) Bit rate                                        : 10 Gb/s

ii) Repeater spacing                      : 100 km

iii) Operating wavelength              : 1.55 µm

Fourth Generation

Fourth generation uses WDM technique

Bit rate                                           : 10 Tb/s

Repeater spacing                          : 10,000 km

Operating wavelength                   : 1.45 to 1.62 µm

Fifth Generation

Fifth generation uses Roman amplification technique and optical solitiors.

Bit rate                                           : 40 – 160 Gb/s

Repeater spacing                          : 24000 km – 35000 km

Operating wavelength                   : 1.53 to 1.57 µm