Photonic nanowires directly drawn from bulk glasses

Abstract

High-uniform nanowires with diameters down to 50 nm are directly taper-drawn from bulk glasses. Typical loss of these wires goes down to 0.1 dB/mm for single-mode operation. Favorable photonic properties such as high index for tight optical confinement in tellurite glass nanowires and photoluminescence for active devices in doped fluoride and phosphate glass nanowires are observed. Supporting high-index tellurite nanowires with solid substrates (such as silica glass and MgF2 crystal) and assembling low-loss microcoupler with these wires are also demonstrated. Photonic nanowires demonstrated in this work may open up vast opportunities for making versatile building blocks for future micro- and nanoscale photonic circuits and components.

Optical microfibers and nanofibers

“…For materials not available in fiber forms, drawing directly from bulk glass is essential and can expand the MNF materials to a variety of glasses, especially for drawing active MNFs from glasses with functional dopants [84]. Usually, a solid heating element (e.g., a flame-heated sapphire tip) is used to melt the glass and draw MNFs with high uniformity and repeatability.…”

“…Bent MNFs are important building blocks that can be readily assembled into highly compact photonic integrated circuits (PICs) or devices such as couplers [13,84], interferometers [99], resonators [81,96,97], and lasers [34,[52][53][54]56]. Usually, bending losses of conventional fibers can be calculated using weakly guiding or adiabatic approximation.…”

“…With an overlap < 5 μm, the structure working as a 3-dB splitter with an excess loss of < 0.5 dB [13]. For high-index MNFs (e.g., tellurite glass MNFs), the light can be well confined and guided along the MNFs even supported by common substrates such as silicate glass or MgF 2 crystal, which offers enhanced mechanical robustness and great convenience for handling compared to silica aerogel substrate [84]. Figure 10A1, A2 shows an optical coupler assembled using two tellurite glass MNFs (with diameters of 350 and 450 nm, respectively) supported by a silica substrate with a refractive index of 1.46.…”

Alkoxide-based precursors for direct drawing of metal oxide micro- and nanofibres

“…For evanescent coupling, the laser beam was introduced into a conventional 50 µm core silica fibre whose tapereddown end (∼1 µm diameter) was brought into contact with a freestanding sol-.gel-prepared fibre supported at both ends (figure 2). The coupling scheme is similar to that used previously for the investigation of various glass and semiconductor nanowires [37,38].…”

Optical microfiber passive components

“…1) The "self-modulated taper-drawing" [1] 2) The flame-brushing technique [2][3][4][5][6] 3) The modified flame-brushing technique [9,12,13] 4) Direct pull from bulk glass [14] The "self-modulated taper-drawing" [1,15] was the methodology firstly published in Nature in 2003. It is a twostep procedure: firstly, a taper with a diameter of few micrometers is drawn from an optical fibre using the conventional flame brushing technique; then, the manufactured taper is cut into two halves in the uniform waist region, and one of the microfibers is wrapped onto a hot sapphire rod and pulled to sub-micrometric diameters.…”