Exercise 1: Calculation of pulse broadening due to Polarization Mode Dispersion in a single-mode fiber optic link




October 15, 2000



A digital binary fiber optic link has the following specifications:


Signaling rate: 10.3125 Gbaud

Type of fiber: Singlemode, per IEC 793-2:1992 Type B1.

Link Length: 49 kilometers.

Transmitter laser center wavelength: 1550 nm

Laser spectral width, RMS, max: 0.3 nm

Laser type: DFB, single longitudinal mode

Polarization Mode Dispersion Link Design Value: 0.5 ps/sqrt(km), measured in compliance with IEC SC 86A/WG1, Method 1, September 1997.


Calculate the value of time domain pulse spreading, in psec, that can occur from PMD alone, with a probability of 10^-12. If there is an alternative approach to doing this exercise for example, in terms of number of seconds of outage per link per year, with outage defined as a certain value of pulse spreading in psec you may use that approach. Please remember to specify the assumptions you make. Ignore the effects of jitter and chromatic dispersion. Assume that the PMD effect of the entire link is from fibers only, is statistical in nature, and is based on strong mode coupling. There are no optical amplifiers or dispersion compensating elements in the link.


You may email your reply to the Equalization Ad Hoc reflector, or send a file to me, and I will arrange to post it on the web.



Vipul Bhatt





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Last Update: 15 Oct 00



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