Laser LAN

[allthatwhichis]

I did a quick Google search and then stopped... as most of the experts are here. I figure I'd bring the topic up here and see what the experts think.

I'd like to take a couple red or blu-ray modules and make a laser LAN connection between two PCs to see if it can be done in a cheap manner. For no better reason except the idea is stuck in my head.

What specific parts are needed, assuming it is worth the effort.

[300EVIL]

Well, the basics would be one transmitter laser diode and a receiving photodiode on one end and the exact opposite on the other end. Maybe using two different diode wavelengths and filters in front of the PD's would prevent crosstalk with large distances. You would need some fast and clean LD drivers I'd imagine as you are dealing with well into the Mhz range, that part may be expensive and/or tricky. Converting the signal from the ethernet to modulation for the LD driver should be easy though.

[Xer0]

I had this idea some time aog too and discussed it with an pro on my practica

The hard part is to get an OPamp capable of working clean with signals in a 3-digit-Mhz range and to isolate every disturbing HF on the board.

[Pitts]

Its been done and is commercially available. I cant remember the brand off hand. It looks like a pair of binoculars from memory..
So if your doing it for some fun there is hope of an outcome.
If you just want to buy it pm me and I will see if I can dig up the info.

cheers

Ray

[allthatwhichis]

So... HeNe and an AOM? I thought even the Maxyz driver would do 100 to 200Mhz.

[300EVIL]

If you want to play around, I have a pair of these I can send you. http://www.transition.com/Transition...ete/man02F.PDF

In theory you can maybe just replace the TX LED with a laser diode and see what happens. I have a pair here I'm messing with right now. In fact, this post is being sent over fiber optic transceivers I just setup a few minutes ago.

[300EVIL]

Its been done and is commercially available. I cant remember the brand off hand. It looks like a pair of binoculars from memory..
So if your doing it for some fun there is hope of an outcome.
If you just want to buy it pm me and I will see if I can dig up the info.

cheers

Ray

Yeah, a lot of companies make them.

http://www.aldernetworks.co.uk/laser.html

http://www.airlinx.com/products.cfm/product/19-0-0.htm

http://www.mdatechnology.net/techprofile.aspx?id=536

[flecom]

if you really want to roll your own i would pick up a pair of media converters off ebay or something and then use those as a base for your setup... i would stick with short wave stuff sooo

10baseFL
100baseFX
1000baseSX

remember both ends have to be the same (i had to explain this to a network engineer a few weeks ago, wondering why 1000baseSX wouldn't link with 100baseFX... sigh)

[Daedronus]

DIY light links, last time I looked they had 10Mpbs.

http://ronja.twibright.com/