Preparation and characterization of a large mode area liquid-filled photonic crystal fiber: transition from isolated to coupled spatial modes

We describe in detail the manufacturing procedures for selectively closing holes in photonics crystal fibers and their infiltration with different liquids. We apply our method to create a large mode area liquid-filled photonic crystal fiber which consists of 19 liquid strands. By changing the mixing ratio between toluene and ethanol and by varying the temperature, we show continuous tuning from isolated to coupled behavior of the spatial mode profile. This demonstrates the versatility of selectively closed liquid-filled photonic crystal fibers for future photonic devices. Filling with nonlinear liquids, gases, metals, liquid crystals, low melting compound glasses, or quantum dots is possible, and spatial as well as temporal engineering of linear and nonlinear optical properties will become feasible, which should allow the observation of spatiotemporal solitons.