Optics question - carrier waves

In summary, the conversation discusses the concept of an envelope, which represents the amplitude modulation of a carrier wave and is not well-defined. The conversation also mentions the relationship between the envelope and the frequency of irradiance, which requires more information to fully understand.
  • #1
jaejoon89
195
0
I am trying to understand what exactly the envelope is and why does the irradiance have twice its frequency?

In class my teacher showed that when you sum individual waves, you get the carrier wave. Then my teacher showed something called an envelope, which looks a lot like an oscillating sine wave with lambda = 2pi/k. I guess the envelope shows how the amplitude of the carrier wave oscillates, but what is it exactly? And why does the irradiance have 2x its frequency?
 
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  • #2
jaejoon89 said:
I guess the envelope shows how the amplitude of the carrier wave oscillates, ...
Yes.

jaejoon89 said:
... but what is it exactly?
It is not physical, nor even necessarilly well-defined. It approaches well-defined as fAM/fcarrier → 0, where fAM is the amplitude modulation frequency, and fcarrier is the carrier frequency.

jaejoon89 said:
... why does the irradiance have 2x its frequency?
I think we need more information to help you understand this. It seems like there is some special condition that you are neglecting to mention ...
 

FAQ: Optics question - carrier waves

1. What is a carrier wave in optics?

A carrier wave in optics refers to the electromagnetic wave that carries information, such as light or radio signals. It is a continuous wave that is modulated by the information being transmitted, allowing it to be easily detected and decoded.

2. How does a carrier wave work in fiber optic communication?

In fiber optic communication, a carrier wave is used to carry data signals through the optical fiber. The data is first converted into light signals, which are then combined with the carrier wave. The resulting signal is then transmitted through the fiber and can be decoded at the receiving end by separating the carrier wave from the data signal.

3. What is the importance of a carrier wave in optics?

A carrier wave is important in optics because it allows for the transmission of information over long distances without significant loss of signal strength. It also allows for multiple signals to be transmitted simultaneously using different carrier frequencies, increasing the efficiency of communication systems.

4. How is a carrier wave generated in optics?

In optics, a carrier wave is typically generated using a laser or an LED (light-emitting diode). These devices produce a continuous beam of light, which can then be modulated with the desired information to create the carrier wave.

5. Can carrier waves be used for other purposes besides communication?

Yes, carrier waves have various other applications in optics. They are used in radar systems for detection and ranging, in medical imaging devices such as MRI machines, and in spectroscopy for analyzing the chemical composition of materials. They are also used in optical navigation systems for autonomous vehicles and spacecraft.

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