Page 230 - Photonics Essentials an introduction with experiments

Optical Fibers and Optical Fiber Amplifiers

224 Advanced Topics

to 1 bit period, or when the width of 1 pulse at half maximum
is broadened by 50%.
e) Determine the dispersion-limited transmission distance at
these three bit rates.
9.4 Calculate the total information-carrying bandwidth of an optical
fiber in a telecommunications network. Assume that communi-
cations are being sent at the low-loss window between 1530 and
1560 nm, where Er-doped fiber amplifiers can be used.
a) Estimate the channel bandwidth in wavelength (or frequen-
cy) required for modulation at 10 Gbit/sec.
b) If each channel is separated by 1.5 times the modulation
bandwidth, how many channels can be accommodated in the
30 nm transmission window?
c) What is the total amount of information bandwidth that can
be supported by the fiber?
d) Repeat calculations a, b, and c for 40 Gbits/sec.
e) Compare your results with the standard established by the
International Telecommunications Union (called the ITU
Grid). Comment on the differences.

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