Re: LED Frequency Ranges

From: Larry Brasfield (donotspam_larry_brasfield_at_hotmail.com)
Date: 03/17/05 

Date: Wed, 16 Mar 2005 23:24:25 -0800

"LightBoy" <don@nitestarrs.com> wrote in message
 news:1111040989.017475.233240@z14g2000cwz.googlegroups.com...
> Hello,
Hi.
> I am working with some "super bright LED's" - so called - and I have
> been looking for "specs" on the upper limit of how fast (Frequency) at
> which LED's can be modulated. Measureably switched on and off.
>
> I can find nothing doing a Google search on the subject. Can anyone
> give me a place where I can go (on the Internet that is - LOL) where
> such information might be obtainable?

I once tried to find the same kind of data, and found a SLED
(superluminescent diode) with the feature "pulsed operation"
  http://www.nolatech.ru/nolatecheng.htm#b6
I wrote to the manufacturer to see if they would part with
some data as to what that meant, and got a nice reply with
some frequency response data. Sorry I cannot lay hands
on it. (It was for a one-time job.) But you should be able
to retrace that path.

> Or information that you may be
> aware of on this subject? The place I bought these LED's has lots of
> specs - but none relating to this capability.

All I remember was that it was much faster than necessary
to be considered flat in the 100 KHz to 10 MHz band.

You might see if you can find anything on the diffusion
capacitance of GaAs diodes. That relates directly to
carrier lifetime which in turn controls emission frequency
response since emission is directly related to carrier
density/population.

> Thanks so much for any help!
Good luck. You'll need it as I recall. 

-- 
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.