Temperature dependence of LED emission bandwidth

In summary, the spectral purity of an LED is a key factor in the temporal spread caused by material dispersion in an optical communications system. As the LED is cooled, the fermi-dirac state-occupancy probability will more closely approximate a step function, affecting the spread of wavelengths emitted. This is due to the recombination energy being dependent on temperature. Redefining the term "temporal" as resonance may provide a more accurate understanding. Additionally, considering the relationship between surface area, current, load, frequency, and temperature may offer further insights into the temperature dependence of solid state light transceivers.
  • #1
Funtime
3
0

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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  • #2
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.
 
  • #3
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 celcius range, unless of course you wish to get fermiatic on it.
 

1. What is the temperature dependence of LED emission bandwidth?

The temperature dependence of LED emission bandwidth refers to the change in the width of the spectral emission from an LED as the temperature of the LED increases or decreases. This change in bandwidth is due to changes in the energy levels of the LED's semiconductor material, which affects the wavelengths of light that can be emitted.

2. How does temperature affect the emission bandwidth of an LED?

As the temperature of an LED increases, the emission bandwidth typically increases as well. This is because the increased temperature causes the energy levels of the semiconductor material to broaden, allowing for a wider range of wavelengths to be emitted. Conversely, as the temperature decreases, the emission bandwidth decreases due to the narrowing of the energy levels.

3. Why is the temperature dependence of LED emission bandwidth important?

The temperature dependence of LED emission bandwidth is important because it can affect the overall performance and efficiency of an LED. It can also impact the color and intensity of light emitted from the LED, which can be crucial in applications such as lighting and displays.

4. How is the temperature dependence of LED emission bandwidth measured?

The temperature dependence of LED emission bandwidth is typically measured using a spectrometer or spectrophotometer. These instruments measure the intensity of light emitted from the LED at different temperatures, allowing for the calculation of the emission bandwidth.

5. Can the temperature dependence of LED emission bandwidth be controlled?

Yes, the temperature dependence of LED emission bandwidth can be controlled to a certain extent. By using different materials and designs for the LED, the temperature dependence can be minimized. Additionally, proper thermal management techniques can be employed to maintain a consistent temperature and minimize the effects on the emission bandwidth.

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