[Ronja] vcsel-s retail

[Gullik Webjörn]

Hi Martin,

Roithner also has red 670 nm VCSELs. They are low power, but what
matters is the *intensity* on axis. Since the VCSEL has a small
die, many times smaller than a LED, it should be possible to get
much less divergence, based on the same size optics, and focal length.
This is good for power, but bad for alignment, since the spot is
smaller. This probably requires another strategy for alignment,
maybee electronicly aided.

If an alignment system is designed, that does not rely on "eyesight",
then the issue of visible versus IR is less important.

Probably the glass window based vcsels are the best, since you want
a reasonable back focal length, and the epoxy package cannot be
expected to have very good (relative) precision.

What is missing in the datasheets for red vcsels is the switching time,
should be in the 1 nS range, but it is not specified.

You have about 1 mW out, you need more than 1 uW or so, that allows
for a transmission path loss of 30 dB in the VCSEL case.

Gullik


>Everything is fine... if you stay in the IR spectrum.
>if someone could find visible light high power VCSELs, that would be fine...
>Bye,
>Martin