Low loss single mode fiber interconnections for free-space optical switches based on diffractive microlens arrays

International audience; Diffractive microlens arrays with up to 16 phase levels and 0.75 or 1.5 mm pitch have been fabricated to interconnect single mode fiber arrays (including extended mode fibers) in free-space switches. The fiber-to-fiber insertion loss can be in the 2 to 3 dB range at distances up to one meter, with only small (0.2 dB) inter-channel dispersion for one-dimension links. For two-dimension interconnections, the use of extended mode fibers could relax the packaging constraints and reduce the wavelength sensitivity, providing a bandwidth of several tens of nanometers, suited to optical cross-connects.