- This topic has 3 replies, 2 voices, and was last updated 6 years, 2 months ago by
Mohamed A. A. Abouseif.
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February 27, 2018 at 7:09 am #47864
Francis SulikParticipantI was trying to find some information on how to calculate the amount of reflectance, and/or optical return loss for lateral core missalignment of singlemode fibers. Its easy to find charts and formulas for insertion loss lateral offset, but not reflectance / ORL. Does anyone have information relating to this subject or will any of the Optiwave software products calculate this ?. OTDR testing of ORL for missaligned fibers in the field seem to indicate worse ORL for core missalignment, however Ive read that light can travel through the cladding for some finite amount of distance before being attenuated, so Im not sure if worse ORL is light entering the cladding and reflected back to the OTDR detector, or something else.
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March 1, 2018 at 8:04 am #47890
Mohamed A. A. AbouseifParticipantHi Francis,
from power balance principle, if the normalized insertion loss lateral offset is calculated then the normalized ORL could be calculated as well.
as a simple way is to approximate the power is to calculate the overlap areas as a power coupling coefficient.If you are looking for one of rigorous approaches, I think the modal analysis is it.
In brief, to get the complete set of modes (radiation modes and guided modes) for both sides of the fibers then, apply the boundary conditions on the interface area (with lateral offset) to calculate the coupling coefficient. from these coupling coefficient, the reflectance and the insertion loss can be calculated. this method is in general tough (attached paper is following this procedure but different discontinuity situation)In OptiSystem, project this attenuation could be inserted to the loss parameter after the user estimate it.
Hope this help -
March 1, 2018 at 1:03 pm #47893Francis SulikParticipant
Thankyou for the information. The subject matter and mathematical equations are complex so I think it will take some time to digest, however it gives me a good starting point.
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March 1, 2018 at 1:19 pm #47894Mohamed A. A. AbouseifParticipant
you are welcome,
I am one of the authors of this paper long time ago, so feel free to ask if you decided to follow it.best of luck
Mohamed A. Abdelalim Abousif
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