Download fiberoptics project - Deveney-BSU

Free Lasers and the Effects of Fiber Optic Coupling
Adam Manganiello, Colin Gregory, Scott Johnson
Department of Physics, Bridgewater State University // Bridgewater MA, 02324
Mentor: Dr. Deveney
Abstract:
Future Trials:
In the study of Fiber Optics, one has many options to choose from in
terms of what Fiber Optics application they are too study. Our group is
employed across varying fields and through collaboration we decided to
investigate the properties of a free laser as it emerges from a fiber optic launch
cable. The act of launching the free laser into a fiber optic coupler proved to be
an incredibly daunting task. The goal of coupling the laser took us three weeks
to achieve; in this time we took turns adjusting the alignment screws in a raster
like fashion until coupling was achieved. We maximized the power output and
collimated the beam. At this point we are attempting to obtain a Gaussian beam
profile and are investigating the potential to use out laser system for
communications.
In the coming months we look forward to obtaining a proper
Gaussian Beam profile with a much higher degree of precision. If time
permits we would also like to program an interface and microcontroller in
order to modulate the power of our laser so that we may be able to send
and receive a viable communications signal. Due to the difficulty of coupling
the free laser into the fiber optic launch cable, we are behind schedule in
terms of achieving our communications goal.
Findings:
In our trials we have found that ~60 percent of the
power of a 5mw laser is lost due to fiber optic coupling. Although
the loss percentage is quite high, one is still left with a usable,
collimated laser output. In figure one, although not entirely precise,
one may view a traditional Gaussian Beam profile. At the center
point of the beam (1 Degree on the rotational stage) one may
observe a power output of .87mW.
Gaussian Approximation
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Acknowledgements:
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Fiber optics are put to use everywhere from color change Christmas
trees to high speed communication. The essential properties of how a beam
propagates through a now fiber optic cable where first observed with light shining
into a barrel of water and propagating through a stream of water emerging from
the base of the container. It wasn’t until the 1970’s when Corning Glass Works
patented high-silica glass fibers that we would see efficient communications past
one kilometer. Today most industrial networks employ a fiber optic
communications backbone due to its reliability and high speed capabilities.
Power (mW)
Fiber Optics:
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Dr. Deveney and the Adrian Tinsley Program
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Gaussian Profile Data
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Degrees
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Figure 1: Figure one is a graphical interpretation of the data that we
obtained by rotating our collimated, optically coupled, laser output
through two degrees of rotation on a rotational stage.