[Laser] Light Communications Questions.

[Stan]

Hello The Net:

I have accumulated some questions:

1. Looks like power LEDs are advancing nicely, with respect to actual 
light power output (lumens).
Any thoughts as to the applicability to light communications ?
I just got in a 5W ( 3 x AAA batteries) flashlight and it looks like the 
single LED is fed DC power
directly from the battery bank. No driver module. No idea how many 
lumens it puts out.
Colored filters (band pass filters) are not commonly available for it yet.

Ebay also has listing for a 12W, single LED, flashlight, using 2 each 
CR123A ( 3.7V @ 1000 mAh)  batteries.


2. Any idea what the band pass of the Kodak red wratten sheet filter 
material is ?
 Yes red, but 627 or 635 nM ?  or 600 or 7000 nM,  half power bandwidth ?

3. Any know issues with modulating the higher power LED sources ?
Can they handle 10 MHz modulation or is there severely limited
frequency response due to the actual (large) die construction ?

I have seen current sourcing "dimmable"  drivers, but I expect the 
frequency to be in the low audio range.

4. I am looking for a source of larger acrylic fresnel lenses.
At one time this reflector pointed me to a Asian source, but I have lost 
the reference.

I am still in the thinking stage.

Thanks for the assistance,
Stan, W1LE    FN41sr   Cape Cod




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