Optical Limiting in a Single Mode Waveguide System

Abstract

The objective of this Trident project is to study the optical properties of single mode waveguide systems that exhibit an absorption that increases with the intensity of the light incident upon them. In this way these devices limit the transmission of optical energy and are referred to as optical limiters . Such systems are of great value to both the military and the telecommunications industry because of their ability to protect sensitive equipment from exposure to high intensity light. Experiments were performed using very small glass capillaries filled with materials that exhibit a nonlinear absorption. In this case, the materials absorb a greater amount of light as the intensity increases. These systems act as waveguides, confining the light to a small core region where the nonlinear material resides. Furthermore, only one intensity distribution (or mode ) is allowed if the index of refraction of the core is very close to that of the surrounding glass. In this case, the waveguide is called single mode. Single mode behavior was achieved by controlling the temperature of the waveguide in order to tune the index of refraction of the core material. Pulses of visible light (wavelength = 532 nm, pulse width = 4ns) were coupled into single mode waveguides and the input and output intensities were measured. These results were compared to optical limiting observed in multi-mode waveguides. It was observed that multi-mode waveguides exhibit better optical limiting than single-mode waveguides. This is because the entire mode structure is confined to the core in a multi-mode waveguide. However, a portion of the mode extends into the cladding in a single-mode waveguide. In addition, single-mode waveguides show a decreased ability to limit at higher temperatures where the difference in index of refraction is smallest.

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Document Details

Document Type
Technical Report
Publication Date
May 07, 2004
Accession Number
ADA425013

Entities

People

  • Jeffrey C. Payne

Organizations

  • United States Naval Academy

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Absorption
  • Absorption Coefficients
  • Computer Programs
  • Energy Levels
  • Ground State
  • Intensity
  • Lasers
  • Light Sources
  • Materials
  • Optical Equipment
  • Optical Properties
  • Optics
  • Refraction
  • Refractive Index
  • Temperature Gradients
  • Two Photon Absorption
  • United States Naval Academy

Fields of Study

  • Physics

Readers

  • Optical Fiber Sensing and Electromagnetic Propagation.
  • Optical Physics and Photonics.