Do you know which aircraft uses fly-by-light
 

It is actually in service. I'm sure there must be several pilots current on type that can tell us what it is like to fly this aircraft.

I suspect it flies like a "normal" aircraft...

Pull back, cows get smaller, push forward, cows get bigger (apologies to the Pruner of similar name... :ok:)

From the user point of view, there is no difference between fly-by-light and fly-by-wire. The primary advantage for fly-by-light is that it is basically immune to EMI/Lightning effects (there may also be some small weight savings if they can get the connector thing figured out). The primary disadvantage is currently the connectors - no one has really come up with a lightweight bulletproof aviation fiber optic quick disconnect that's good for the life of an aircraft.
Fiber optics have been used on IFE systems (starting, I believe, with the original 777) but IFE is generally not considered flight critical.
Boeing did a project back around year 2000 where they installed fiber optic throttle resolvers on a 757 for in-service evaluation (it didn't actually control the engines, just fed a box out on the engines that recorded data). Throttle resolvers are a particularly attractive use since the wiring goes outside the pressure vessel and hence is exposed to the full EMI/Lighting threat - but it's also a very difficult challenge for the connectors since the on-engine connectors are frequently disturbed in a potentially dirty environment..

Kawasaki P-1 "Japanese Poseidon"
 

Given that the P-1 first flew about a year and a half before the P-8 Poseidon, shouldn't it be the other way round ? :O

Thanks goodness we have tdracer replying in this thread. Thank you as usual for your informative post.

I have distant memories of Smiths Industries flying a prototype optical fibre system in a BAC 1-11 (G-ASDJ ?) as a joint research venture with BAe and RAE; late 1970s.
My memory was that the fibre link was to be, or was part of a reduced stability control system.
The aircraft was aft cg loaded, further destabilised with lead wts moved aft during flight. This aspect of the tests complemented the RAE Bedford work on reduced stability in their BAC 1-11 (XX105) which used artificial destabilisation.