Chemically-etched optical fiber tapers for adiabatic fundamental mode evolution over O- and C-bands

The adiabatically tapered subwavelength-scale optical fiber tapers (OFTs) have been of interest for many photonic applications. We demonstrate chemical etching-based adiabatic OFTs and their relaxed adiabaticity conditions over broad operation wavelength ranges. The etched OFTs show adiabatically-varying tapering angles as small as 1 and mechanical flexibility. When compared to the conventional methods, the proposed OFTs and their fabrication techniques may allow reproducible batch production routes for adiabatic OFTs with enhanced uniformity, enabling a variety of applications in subwavelength-scale light-matter interactions and efficient light coupling between waveguides.