COUPLING EFFICIENCY FOR SINGLE MODE FIBERS Drexel ECE

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COUPLING EFFICIENCY FOR SINGLE MODE FIBERS Drexel ECE Powered By Docstoc
					COUPLING EFFICIENCY FOR
SINGLE MODE FIBERS AND
 FIBER-OPTIC ALIGNMENT
      AUTOMATION


     A PRESENTATION BY:
       Shubham Bhat
       skb25@drexel.edu
                            Overview


• Gaussian Beam analysis
• Losses (Intrinsic and Extrinsic)
• Mechanical misalignments (Lateral, Longitudinal and Angular)
• Fiber-optic alignment automation
• Hill-climbing algorithm
• Drawbacks of hill-climbing algorithm
• A proposed novel feed-forward controlling algorithm
• Conclusion
Gaussian Beam
                             Coupling Efficiency



      Source Efficiency




     = Source wave function              = Modal wave function




Power- Coupling efficiency




         Total efficiency
Coupling Efficiency Contd.
                                 Losses

                                 LOSS




Intrinsic losses           Reflection losses   Extrinsic losses
• NA effects                                   • Lateral Misalignment
• Fiber-radius effects                         • Longitudinal Misalignment
• Index-Profile effects                        • Angular Misalignment
• Core concentricity within cladding
• Fabrication tolerances
Longitudinal Misalignment
Angular Misalignment
Lateral Misalignment
  Current technology




6 DEGREES OF FREEDOM
Array Waveguide Grating PLC
Fiber-Fiber Alignment Automation
Drawbacks of Hill-Climbing




 Cutting off at Local Maxima
    Hill climbing Vs Smart Algorithm


Smart Algorithm




                  Hill climbing algorithm
Smart Algorithm
                       Conclusion



• Longitudinal misalignment is less critical than angular and lateral
  misalignment.

• Dominant loss arises from lateral displacement in single mode
  fibers.

• Hill-climbing algorithm is time-consuming and has the potential
  drawback of missing the actual peak.

• A novel Algorithm using a feed forward controlling technique is
  proposed which takes care of the disadvantages of hill climbing
  method.

				
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posted:10/18/2012
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