3D printing specialty multi-function twin core Bi/Er co-doped silica optical fibres for ultra-broadband polarized near infrared emission and sensing applications

With the advent of the smart information network, optical fibre is evolving from a telecommunication medium to a network device with multiple functions, from laser amplification to distributed sensing. This increasing added function of optical fibre is posing new challenges for specialty optical fibre manufacture. In this article, twin core bismuth and erbium co-doped silica optical fibre (TCBEDF) was manufactured using 3D printing technology. This approach effectively avoided the tedious steps involved with traditional chemical vapour deposition (CVD) technology, such as deposition, doping and drilling, greatly simplifying the manufacturing process of optical fibre preforms. The fabricated TCBEDF has potential emission and sensing applications. The broadband luminescence over wavelength span Δλ ∼ 950–1600 nm was obtained under laser excitation at λ = 830 nm. At the same time, the dual core structure, despite some distortion in profile, provided a polarized ultra-broadband fluorescence. In addition, the dual core structure was used to construct a Mach–Zehnder interferometer (MZI) to demonstrate the sensing of multiple parameters, including temperature, refractive index, stress and bending.