High-power continuous-wave optical waveguiding in a silica micro/nanofibre

Abstract

As miniature fibre-optic platforms, micro/nanofibres (MNFs) taper-drawn from silica fibres have been widely studied for applications from optical sensing, nonlinear optics to optomechanics and atom optics. While continuous-wave (CW) optical waveguiding is frequently adopted, so far almost all MNFs are operated in low-power region (e.g., <0.1 W). Here, we demonstrate high-power low-loss CW optical waveguiding in MNFs around 1550-nm wavelength. We show that a pristine MNF, even with a diameter down to 410 nm, can waveguide an optical power higher than 10 W, which is about 30 times higher than demonstrated previously. Also, we predict an optical damage threshold of 70 W. In high-power CW waveguiding MNFs, we demonstrate high-speed optomechanical driving of microparticles in air, and second harmonic generation efficiency higher than those pumped by short pulses. Our results may pave a way towards high-power MNF optics, for both scientific research and technological applications.

Optical microfiber or nanofiber: a miniature fiber-optic platform for nanophotonics

“…Also, by controlling the supply current, the heating temperature can be controlled much more precisely and conveniently than the flame. Figure 5 shows photographs (b) Schematic (upper, not to scale) and experimentally measured (bottom) fiber diameter evolution of a biconical drawn silica MNF along the fiber length [54] . The MNF has a diameter of about 930 nm and a uniform length of 9 cm.…”

“…With the above-mentioned high-precision diameter control technique, MNFs with accurate diameters and excellent diameter uniformity can be fabricated with good reproducibility, which have found applications in MNF Fabry-Pérot (FP) cavities [53] and high-efficiency harmonic generation [54] . Besides the high-order-mode cutoff, the scattering intensity of waveguiding evanescent fields has also been used for real-time diameter control [52] .…”

“…The point defects on the MNF surface will give rise to an increase in surface roughness and optical absorption, resulting in additional optical losses. It is worth mentioning that the photothermal effect induced by optical absorption is prominent when the MNFs are operated under high optical power [54] . As shown in Fig.…”

“…To further enhance the interaction between the waveguiding mode and matters within the mode field, the most straightforward method is increasing the waveguiding power in the MNFs. Recently, Zhang et al reported high-power CW optical waveguiding in high-quality silica MNFs around 1550-nm wavelength [54] . As seen in Fig.…”

“…Inset: photograph of an MNF-embedded PDMS patch attached to a human hand. (b) Photograph of an optical MNF sealed in an airtight 3D-printed acrylic box, filled with high-purity nitrogen gas [54] rate, they predicted an acceptable decrease of ∼10% in the optical transmittance after more than 4 years. Recently, Zhang et al transferred an as-fabricated 1.2-μm-diameter MNF into a 3D-printed acrylic box protected by high-purity nitrogen gas [see Fig.…”