What exactly does a photonic switch do?

[Mark R]

Text

 

[jlazzaro]

photonic switch = an all optical fiberoptic switch

the main difference between this and traditional fiber switches is they maintin the signal as light from input to output. traditional switches convert the photons from input to electrons to do the switching, then back to photons on the output.

true optical switches support ALL transmission speeds unlike electronic switches, which are tied to specific data rates / protocols. optical switches direct the incoming bitstream via tiny mirrors to the output port no matter what the line speed or protocol (ie atm, ip, sonet)

unless you handle massive amounts of data such as an ISP, not something your going to take advantage of.

 

[Mark R]

Oh right. So essentially, it's like a patch panel or manual switch box. You select port 1 to connect to port 16, etc.

As it's protocol independent, presumably that means it can't route or switch in a directed manner (like, say, an ethernet switch) - unless there is a gross problem such as a disconnected fiber, in which case presumably it could detect that and implement a pre-programmed work around.

 

[jlazzaro]

precisely 🙂 these mirrors are so small they can literally fit through the eye of a needle.

fiber diagram

 

[Mark R]

sweet. thx.

 

[cmetz]

The other thing in photonic switching is lambda to lambda switching, for WDM setups. So you can switch port 1 color 1 to port 2 color 5 and port 1 color 2 to port 16 color 2, and that can be reconfigured.

As a result, you can define one fiber with something like 32 lambdas and arrange in your optical network that each of 32 destination cities are optically cross-connected to you. It's like having a direct optical circuit to each of those cities, at least as far as your routers are concerned, and you have some hope of reconfiguring the network on failures. I believe there are even boxes that map MPLS labels to colors, so you can have one fat OC line out of your router and map MPLS virtual circuits to these WDM colors on real optical circuits.

Fun stuff.