Vlakenske naprave za dostop do evanescentnega polja
Nanowire-based refractive index sensor on the tip of an optical fiber

This letter presents a refractive index sensor created at the tip of an optical fiber that utilizes silica nanowire within a radius of between 225?nm and 600?nm, as a sensing element. Sensitivity in excess of 800?nm/RIU was demonstrated within an aquatic medium, while the entire sensor structure was shorter than 1?mm with a diameter equal to or less than the standard fiber diameter. The presented sensor structure is made entirely from silica and provides the mechanical protection of sensitive nanowire. The proposed sensor is thus a robust and self-sustained structure, which does not require any complex packing.

Miniature micro-wire based optical fiber-field access device

This paper presents an optical fiber-field access device suitable for use in different in-line fiber-optics systems and fiber-based photonics components. The proposed device utilizes a thin silica micro-wire positioned in-between two lead-in single mode fibers. The thin micro-wire acts as a waveguide that allows for low-loss interconnection between both lead-in fibers, while providing interaction between the guided optical field and the surrounding medium or other photonic structures. The field interaction strength, total loss, and phase matching conditions can be partially controlled by device-design. The presented all-fiber device is miniature in size and utilizes an all-silica construction. It has mechanical properties suitable for handling and packaging without the need for additional mechanical support or reinforcements. The proposed device was produced using a micromachining method that utilizes selective etching of a purposely-produced phosphorus pentoxide-doped optical fiber. This method is simple, compatible with batch processes, and has good high-volume manufacturing potential.

In-line higher order mode filters based on long highly uniform fiber tapers

This paper presents a simple and effective design of taper-based higher order mode (HOM) filters that can effectively remove HOMs from the few-mode fibers. For this purpose, a taper manufacturing technique that allows the production of long and highly uniform tapers was developed. A filter performance was demonstrated on a standard single-mode telecommunication fiber operating at 850 nm. The HOM suppression was better than -39 dB, and the insertion loss of the fundamental mode was less than 0.15 dB.