Can you channel laser light with fiber optic cable?

[LanceLink]

Can you direct or bend or channel a laser light using standard fiber optic cable and maintain the wave length?

 

Thanks

[swansont]

Yes, that's basically the whole point of using fiber optics. A large chunk of our communications is done via lasers over fiber optics. The fibers only support certain wavelength ranges, though. You can't use an arbitrary value. Most telecom fibers work in the near infra-red.

[Enthalpy]

The frequency is kept everywhere as soon as there is no relative motion. The wavelength relates to the frequency, up to a property of the local material called refractive index.

 

So if the light propagated in the fibre comes from air and goes to air, the same frequency means the same wavelength - though the wave is shorter in between, in the fibre's silica. If light comes from GaInAs and goes to Si, the wavelegnth will differ a bit between both semiconductors.

 

If you mean: keep the same wavelength in the fibre as at the transmitter...

- Yes if the transmitter is made of the same material! Especially, some amplifiers are just Er-doped fibres that lase.

- Same wavelength as in air, not with a usual fibre. The index must be bigger than the surroundings in order to channel light.

- More recently, fibres are made of vacuum, with a cladding of so-called "metamaterial" whose index is <1 over a narrow frequency band. These would allow a fast propagation with a wavelength similar to air. Probably what "standard fiber optic cable" excludes.

 

By the way, laser light is the easy one to inject in a fibre. Incoherent light is difficult to focus to a small area, which needs a steep convergence angle that a fibre doesn't channel.