Where to Buy Fibers

For single-mode fibers:

• What is the cut-off wavelength? (Below that wavelength, the fiber will be multimode.)
• What is the effective mode area or mode radius? (There are special large mode area fibers.)
• (The core diameter and numerical aperture are usually not relevant, if the mode area is known.)
• What are the propagation losses (in dB/km)?
• Does it need to be polarization-maintaining?

For multimode fibers:

• What is the core diameter?
• What is the numerical aperture? (This determines the maximum beam angle with respect to the fiber axis.)
• What is the core shape – circular, elliptical, rectangular?
• Is it a pure silica core and a depressed cladding, or a doped core and pure silica cladding? (This might be relevant e.g. concerning parasitic losses or nonlinearities.) There are also plastic optical fibers.
• For telecom fibers: do you need a graded-index fiber with low intermodal dispersion?
• What are the propagation losses (in dB/km)? (They are actually mode-dependent, so one cannot expect a simple specification to be precise.)

General aspects:

• How tight bending is possible, before the bend losses become too high?
• How much optical power can the fiber tolerate? (Additional properties at the launch end may still occur if too much power gets to the coating.)
• What is the outer fiber diameter with and without protective coating?
• What is the coating material? Is it a standard material which can be removed with a usual fiber stripper?
• Can the fiber be cleaved with a standard fiber cleaver? (Fluoride fibers, for example, have quite different mechanical properties than silica fibers.)

For active fibers, look at the check list for rare-earth-doped fibers.

See also our high-quality tutorials on passive fiber optics and fiber amplifiers!

In case that you need additional advice, consultancy from RP Photonics may be the solution.