What Happens When Two Wavelengths Are Modulated at the Same Frequency?

Click For Summary

Discussion Overview

The discussion centers on the effects of modulating two different wavelengths of light (2.0 µm and 1.5 µm) at the same intensity modulation frequency. Participants explore whether sidebands would develop around each wavelength and how the signals might interact, considering both linear and nonlinear optical effects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether sidebands would develop around each wavelength when modulating 2.0 µm and 1.5 µm light at the same frequency, suggesting the possibility of a complex sideband structure.
  • Another participant argues that unless nonlinear optical effects are present, the two wavelengths would not interfere, and their spectra would simply add together.
  • A different viewpoint states that if the light is amplitude modulated by a sine wave, each carrier would have sidebands on either side, with no interaction between the carriers or their sidebands, provided the modulation frequency does not cause overlap.
  • One participant confirms that sidebands would develop around each wavelength, but asserts that the interaction would not lead to a more complex sideband structure, assuming a linear system.

Areas of Agreement / Disagreement

Participants express differing views on whether the two wavelengths would interfere or simply add together. While some assert that sidebands will develop without interaction, others suggest that nonlinear effects could change the outcome. The discussion remains unresolved regarding the complexity of the sideband structure.

Contextual Notes

Assumptions about linearity and the nature of the modulation frequency are critical to the discussion, and the potential for nonlinear optical effects is acknowledged but not fully explored.

MS1984
Messages
1
Reaction score
0
hi

what would happen if i modulated two wavelengths with the same intensity modulation frequency?

for example if i had 2.0um light and 1.5um light and modulated them both with the same frequency, would sidebands develop around each wavelength? or would they interfer in a more complicated way, giving a more complex sideband structure?

thanks, let me know if you need me to clarify this at all
 
Science news on Phys.org
Unless you have some nonlinear optical effects I don't see how they would interfere at all. The spectra of each individual modulated signal should just add, no?
 
If the light is amplitude modulated by a sine wave, then each carrier would have a side band on each side. There would be no interaction between those carriers or their sidebands. That is so long as the modulation frequency was not so high that the sidebands overlapped.

This is the same signal scenario as the AM radio band.
 
MS1984 said:
for example if i had 2.0um light and 1.5um light and modulated them both with the same frequency, would sidebands develop around each wavelength?
Yes, just like any other amplitude modulated signal.

MS1984 said:
or would they interfer in a more complicated way, giving a more complex sideband structure?
No, just like any other amplitude modulated signal.

This of course assumes the system is completely linear. The waves cannot interact in a linear system other than interference pattern like effects.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 15 ·
Replies
15
Views
5K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 22 ·
Replies
22
Views
1K
  • · Replies 7 ·
Replies
7
Views
5K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 5 ·
Replies
5
Views
3K
Replies
2
Views
3K
  • · Replies 20 ·
Replies
20
Views
3K
Replies
3
Views
2K