Four-Wave Mixing (FWM). Definition: Nonlinear effect that occurs in nonlinear optical materials such as photonic switch, optical fiber cable, etc. This interaction between waves leads to interaction between channels. The effects of FWM.
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Definition: Nonlinear effect that occurs in nonlinear optical materials such as photonic switch, optical fiber cable, etc. This interaction between waves leads to interaction between channels
The effects of FWM
generates one or more new channels (or harmonics). For instance, when three waves at frequencies fi, fj, and fk traverse a fiber they generate another signal located at
Example : The input is two signals located at 1 and 2 traverse a fiber of length (L) and the output is four different signals located at 1, 2, 21 - 2, and 22 - 1 .
Where Pi , Pj , Pk are the input power of the channels
D is the degeneracy factor 3 and 6 for two-tone and 6 for three-tone product
And is given by
Where Aeff is the effective cross-sectional area and Leff is the effective length of the fiber given by
The efficiency η is given by
fmn = fm - fn, (m,n = 1, 2, 3)
The following figure demonestrate the effect of FWM when Four signals with equally power 3mw traverses a fiber with the following specifications
Attenuation factor ()
Effective fiber cross-sectional area ( Aeff )
Third order nonlinear susceptibility (1111)
Chromatic dispersion (Dc)
Dispersion slope ( )
Wavelength ( )
The newly generated signals and their corresponding power in dBm after filtration
The original and the newly generated signals after filtration as well as their corresponding power in dBm
Noise Contributions in Optical Systems and detection filtration as well as their corresponding power in dBm
I. Thermal Noise:
K is Boltzmann’s constant, T is the absolute temperature in Kelven, B is the receiver electrical bandwidth and R is the load resistance value.
II. Shot Noise
Where q is the electronic charge, I is the mean optically generated current and Id is the photo detector dark current
III. Relative Intensity Noise (RIN):
Where is given by
The noise due to FWM phenomenon is given by [Reference]
The bit error rate (P [Reference]e) versus the quality factor Q
Now, the question coming at this juncture how to include the effect of FWM in the fiber metrics