Light transmission in multiple or single subwavelength trefoil channels of microstructured fibers.

Optics express

PubMedID: 19494989

Moison JM, Apetrei AM, Levenson JA, Melin G, Pedeboseq P, Fleureau A, Lempereur S, Gasca L. Light transmission in multiple or single subwavelength trefoil channels of microstructured fibers. Opt Express. 2005;13(4):1193-201.
We evaluate the trefoil channels present between the holes of microstructured fibers as a potential dense array of small waveguides. In channels with an inner radius of 330nm, calculations indicate possible propagation with a mode waist of ~350nm at lambda=670nm, near to the diffraction limit. Actual measurements have been performed on a 1-meter fiber section, with injection by a microlensed fiber and mapping of output by near-field scanning optical microscopy. They show that light can be output in individual channels or in several of them, depending on the injection. The observed waist is ~500nm, possibly due to experimental widening. Estimated propagation losses are <20dB/m. Since each channel occupies only 2microm2, this structure opens a way to dense parallel optical processing.