hello ,
modulation is process by which some Characteristic of carrier wave (amplitude , frequency phase) varied according to modulating signal. this process called modulations

carrier signal - EM wave
modulating signal - image , music, speech signal

what is optical modulator ? what is optical modulations ?

 

ask google.......

 

ok according to my search ''modulation is process by which some Characteristic of optical carrier wave (amplitude , frequency phase) varied according to modulating signal. this process called optical modulations. I am not sure

 

Some Fender guitar amplifiers used this for a "reverb" in them. Basically a neon light bulb and a photo transistor bound together to make the modulation. There was a recent tread over at ETO forum about them.

 

Optical modulation has one more, polarization. You can modulate polarization of the laser beam, and measure a sugar level.

 

By optical modulation, do you mean modulating a light beam?
What are you trying to do?

 

hello ,
modulation is process by which some Characteristic of carrier wave (amplitude , frequency phase) varied according to modulating signal. this process called modulations

carrier signal - EM wave
modulating signal - image , music, speech signal

what is optical modulator ? what is optical modulations ?

The same concepts with electricity can be used to modulate light to send information. Fiber optics is one example. You can also encode audio signals into a pwm signal and send it as IR light to a receiver that filters out the pwm frequency and passes the audio portion. It can then be amplified and listened to. The old Mimms books have several encoding methods listed for LEDs. PWM is just one example.

 

Found the thread about light modulated reverb/tremelo. http://www.electro-tech-online.com/threads/what-is-this-what-does-it-do.143593/#post-1207468