one of the companies on my stock watch list makes products that modulate
light waves for electronics uses. Optical nubiate. etc or something.
Light cant be measured by frequency right.?? How could you read little
bits of modulated light waves. ?? Would it be similar to radio freq. ??

 

Probably modulating light for use on fiber optics. On-Off, not AM or FM or quadrature shift.

 

I believe that some of the old laser based distance measuring equipment had a light modulator that could modulate the intensity of the aggregate laser beam.

hgmjr

 

I once maintained some fax machines which "modulated" the laser beam with a varying degree of partial blockage.

 

Since light is the same kind of electromagnetic radiation as radio waves it certainly can be "measured in frequency". It follows the the same relationship as radio waves, namely:

c = f * lambda
 
where c is the speed of light, approximately 3e8 meters/second
and f is the frequency in Hertz
and lambda is the wavelength in meters

 

Indeed so, visible light occupies the portion of the electromagnetic spectrum between ~450 and 750THz.

Dave

 

And wavelengths of 400 nanometers to 700 nanometers

 

The beauty of using light, is that you can use several wavelengths in one cable, and they won't interfere, since they can be separated by simple optics.

 

Thus we have "multimode" fiber!

 

i thought multimode cable transmitted light at the same wavelength, but in several different reflection angles within the cable

 

Yes. Multiple propagation modes allow effective transmission at different simultaneous wavelengths. As an example, we can transmit at 850u while recieving at 1300u. (Assumes we are using the expensive cards.)

In common practice, only one wavelength is used, and xmt/rcv are on different fibers. This uses affordable cards.