To me, the noise in fiber should be related with any unwanted signal or perturbation in fiber which deteriorates the quality of propagating information signal. While characterizing a conventional fiber, we come to across the attenuation (various types), dispersion (various types) and non-linear effects (again various types) of signal with various reasons may be considered as Noise in Fiber. Same approach may be expended to PCF.

With best wishes,

Thanks Professor Arya for nice information but I want to calculate channel bandwidth. Should we consider Shannon theorem (http://www.inf.fu-berlin.de/lehre/WS01/19548-U/shannon.html) to determine Channel BW ? What should be expression for channel BW for COF and PCF?

Dear Prof. Gopinath,

Thank you very much for attention. As far as fiber bandwidth is concerned, it is basically limited by dispersion occurred in fiber. If the fiber cane be treated as a linear system, then transfer function gives is characteristics. In short and coming directly on 3dB fiber bandwidth as follows:

For lightwave systems operating far away from the 1310 nm (zero dispersion), which is generally a case working at 1550nm, the transfer function is approximately Gaussian and 3dB fiber bandwidth approximately equal to 0.188*(Mod(D)LSigma)^(-1) where D is dispersion parameter, L is length of fiber, sigma is RMS source spectral width.

For more details please read page 53, chapter 2 of book Fiber Optic Communication System by G. P. Agrawal, 3rd Eds. These details are for COF. I do not have idea about PCF's bandwidth.

Thanks Prof. Arya for lucid and vivid explanation. I am seeking expression for 2D photonic crystal waveguide. I am requesting you , kindly inform if you find the same in future. Again many thanks.

Ok sir, with regards and best wishes

Thanks sir,

I am deriving a new formula pertaining to PCF. I SHALL INFORM ABOUT THE SANE