Temperature dependence of LED emission bandwidth

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SUMMARY

The discussion focuses on the impact of temperature on the emission bandwidth of LEDs used in optical communication systems. As the LED cools, the spectral purity, defined as the ratio of the wavelength spread (delta lambda) to the central wavelength (lambda), increases due to the Fermi-Dirac distribution approximating a step function. This change affects the temporal spread caused by material dispersion in the fiber, which is influenced by the dispersion parameter that is specific to the fiber's refractive index. The relationship between recombination energy and temperature is crucial for understanding these effects.

PREREQUISITES
  • Understanding of Fermi-Dirac statistics
  • Knowledge of optical fiber dispersion parameters
  • Familiarity with LED operation principles, specifically electron-hole recombination
  • Basic concepts of spectral purity in optical communications
NEXT STEPS
  • Research the effects of temperature on LED spectral purity
  • Learn about the dispersion parameter in optical fibers and its calculations
  • Explore the relationship between recombination energy and temperature in semiconductors
  • Investigate the implications of material dispersion on optical communication system performance
USEFUL FOR

Optical engineers, telecommunications professionals, and researchers in semiconductor physics will benefit from this discussion, particularly those focused on improving the performance of optical communication systems using LEDs.

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Homework Statement


If an LED is used in an optical communications system, explain what would happen to the temporal spread caused by material dispersion in the fibre as the LED is cooled

Homework Equations


(having trouble using the latex equation editor, sorry)
I know that the temporal dispersion is proportional to gamma- the spectral purity (delta lambda / lambda), and the dispersion parameter- wavelength squared multiplied by the double differential with respect to wavelength of the fibre's refractive index.

The Attempt at a Solution


The spectral purity will be the key variable as the dispersion parameter is a function of the fibre alone. I know that as the LED cools, the fermi-dirac state-occupancy probability will more closely approximate a step function, but I'm having difficulty visualising how that will affect the spread of wavelengths emitted. Am I at least along the right lines so far?
 
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The light emitted by the LED is due to electron-hole recombination, right? The energy released in this recombination sets the frequency of the emitted light. So you're on the right track, I think, and you need to think about how the possible recombination energies depend on temperature.
 
I believe you need to redefine what you are looking for as this is a broad term "Temporal", or simplier for this subject resonance.
but here is what I believe is a intriguing idea for temperature dependence on solid state light transcievers.
( surface area sq. * 1 / Current * load / frequency )
(sorry for 2dimensiality), ending in a celsius range, unless of course you wish to get fermiatic on it.
 

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