Optical Fiber Communications 4th Edition by Gerd Keiser

Exercise 14

Verify the plot in Fig. 8.6 of the transmission distance versus data rate of the following system. The transmitter is a GaAlAs laser diode operating at 850 nm. The laser power coupled into a fiber flylead is 0 dBm (1 mW), and the source spectral width is 1 nm. The fiber has a 3.5-dB/km attenuation at 850 nm and a bandwidth of 800 MHz km. The receiver uses a silicon avalanche photodiode that has the sensitivity versus data rate shown in Fig. 8.3. For simplicity, the receiver sensitivity (in dBm) can be approximated from curve fitting by
P R = 9 log B -68.5
where B is the data rate in Mb/s. For the data rate range of 1-1000 Mb/s, plot the attenuation-limited transmission distance (including a 1-dB connector loss at each end and a 6-dB system margin), the modal dispersion limit for full mode mixing ( q = 0.5), the modal dispersion limit for no mode mixing ( q = 1.0), and the material dispersion limit.