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Comment by amatecha | Hacker News Reader

K what? That's amazing! Apparently I need to learn more about lasers.... haha :) I guess it's pretty "fragile" since the slightest misalignment of the source laser & destination sensor would mean a total loss of signal, right?

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Given that the laser forms a spot, minor misalignments are very easy to debug (just line up the red spot with the sensor again). Also given a laser with sufficiently wide spread, minor misalignments would manifest themselves as volume loss.

Not great if you don't have easy access, but reliable enough for e.g. a dorm room or a living room.

This was a lab we did in an intro EE class in college and it worked wonders as a "whoa cool" demonstration with very basic EE knowledge required.

Free space optical system *intentionally" spread the laser beam using a lens. The light beam still consists of parallel rays, and when they hit the receiving lens they focussed again on the receiving diode (or whatever sensor). The idea is to accept that the beam will be disperse in the air, or due to variation at the transmitter, but still to catch enough of the transmission. https://en.wikipedia.org/wiki/Free-space_optical_communicati...

Awesome. Thanks for the wiki link, will check that out.

The other commenter is right, store bought lasers have a descent spread over a few dozen or hundreds of feet. And the signal is still pretty readable to the receiving photodiode.

You’ll probably also need to debug it often on warm summer evenings.

You should find out how the starlink network will communicate if you're worried about accuracy.

Seeing as how Starlink doesn't have this capability, it would probably be better to study any other instance of free-space optics, many of which exist.

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