Dispersion controlled highly nonlinear fibers for all-optical processing at telecoms wavelengths

Abstract

We review our recent progress in the development of lead silicate glass fibers with high nonlinearity and tailored near-zero dispersion at telecommunication wavelengths, encompassing holey, all-solid microstructured and W-type fiber designs. The fabrication techniques and relative merits of each fiber design are described in detail. The optical properties of the fabricated fibers are assessed both experimentally and through accurate numerical simulations. The significant potential of lead silicate highly nonlinear fibers for all-optical signal processing at telecommunication wavelengths is shown via a number of key experimental demonstrators.

Lead silicate glass microsphere resonators with absorption-limited Q

“…The nonlinear refractive index n 2 of the core and the cladding glasses are 41ϫ 10 −20 m 2 / W and 22ϫ 10 −20 m 2 / W at 1.55 m, respectively. 13 The effective nonlinearity ␥ ͑=2 n 2 / ͑ A ef f ͒͒ at 1.55 m of the fiber was therefore estimated to be 225 W −1 km −1 , which is 225 times higher than that of the conventional silica fiber ͑SMF28͒. The propagation loss in the fiber core was measured to be 5 dB/m at 1550 nm using cutback method.…”

Fabrication of multiple parallel suspended-core optical fibers by sheet-stacking

“…4. An asymmetric arc-fusion splicing configuration [20,27], i.e., moving the heating element along the silica fiber from the gap (see Fig. 10(a)), was adopted to splice the borosilicate dual-ASC fiber with a commercial high-NA small core silica fiber (Nufern UHNA4, NA=0.35).…”

“…The dual-core fiber preform was made by extrusion under a temperature around 600 o C. The extrusion method is a well-developed method for making non-silica glass (or so-called soft glass) HF [19] above the glass softening temperature, which is typically below 800 °C. It is very powerful in directly making microstructured preforms with glass features even as small as 7 µm [20]. But due to the lack of suitable die materials capable of working at temperatures above 1000 °C and at high pressures of 0.1-10 kN/cm 2 , the glass extrusion technology has not shown any success in making preforms using glasses with high softening temperature such as silica.…”

A Sheet-Stacking Technique for Making Multiple Air-Suspended-Core Optical Fibres

“…By choosing a glass with lower material loss than N-BK7, e.g., silica as the core, multiple ASC fibres with much lower loss can be fabricated. A commercial fusion splicer was used to splice the dual-ASC fibre to a commercial high NA silica fibre (Nufern UHNA4, NA=0.35) by the offset fusion splicing approach [5], see Fig. 3(c).…”