🚀 go-pugleaf

From: ms15@pyramid.cs.uofs.edu (Michael Schweisguth)
Newsgroups: sci.materials
Distribution: world
Followup-To :  
Reply-To: Ms15@jaguar.uofs.edu
Organization: University of Scranton, PA
Subject: opto-electronics  
Keywords: fiber optics

  hello:
         in my modern physic's lab, which I TA, we are trying to set up
     an experiment to calculate the speed of light using fiber optic
     cable.  We send a pulse first through a 15 cm piece of plastic polymer
     cable and then we send the pulse through a 30 meter piece of plastic
     polymer.  We view the light pulse as it exits from both the 15 cm and 30       meter pieces of fiber optic cable.  The light definetly takes longer to        travel through the 30 meter section then the 15 cm section.  From this         delay, we are able to calculate a value for the speed of light.

          our problem is that the speed of light that we are calculating
     is that of the speed of light in plastic polymer.  we have been trying
     to find the relative permittivity and permeability of plastic polymer
     so that we can transform the results into the speed of light
     in a vacuum.

          we have wondered how important it is to know exactly what kind
     of plastic polymer we are using?  Do different types of plastic fibers         have radically different permittivities and permeabilities or are
     there generally accepted industry standards for these values.  Also,
     a question was raised about how well the process of making the fiber
     relates to the permittivities of plastic polymer.  Does the permittivity
     of a plastic polymer vary widely from batch to batch.

          basically, we are looking for a way to measure our error so that
     when the students do the experiment, we have some idea as to how
     close their results should be. Also, we would like to know how close
     we can get to the value for the speed of light in a vacuum.

       any information pertaining to this topic would be greatly appreciated!

         thanks, 
                 Michael.

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