Integrated liquid-core optical fibers for ultra-efficient nonlinear liquid photonics

Abstract

We have developed a novel integrated platform for liquid photonics based on liquid core optical fiber (LCOF). The platform is created by fusion splicing liquid core optical fiber to standard single-mode optical fiber making it fully integrated and practical - a major challenge that has greatly hindered progress in liquid-photonic applications. As an example, we report here the realization of ultralow threshold Raman generation using an integrated CS₂ filled LCOF pumped with sub-nanosecond pulses at 532 nm and 1064 nm. The measured energy threshold for the Stokes generation is 1nJ, about three orders of magnitude lower than previously reported values in the literature for hydrogen gas, a popular Raman medium. The integrated LCOF platform opens up new possibilities for ultralow power nonlinear optics such as efficient white light generation for displays, mid-IR generation, slow light generation, parametric amplification, all-optical switching and wavelength conversion using liquids that have orders of magnitude larger optical nonlinearities compared with silica glass.

Linear refractive index and absorption measurements of nonlinear optical liquids in the visible and near-infrared spectral region

“…Examples for applications are include selectively liquid-filled photonic crystal fibers [3][4][5][6], and liquid-core optical fibers [7] whose dispersion properties can be tailored accordingly for the formation of a supercontinuum. Liquid-filled patterns in such fibers allow for the realization of directional couplers [8,9], all-optical switching [10] as well as discrete optofluidic spatial solitons in waveguide arrays [11].…”

Integrated hollow-core fibers for nonlinear optofluidic applications

“…To illustrate some of the advantages of this method, Figs. 2(e) and 2(f) show a comparison between an AFLM device and that of the gap-splicing approach [12]. It is clear that the AFLM in Fig.…”

“…Compared to the traditional bulk gas cells and liquid cuvettes, fibers with hollow micro-scale cores can provide high intensities over much longer interaction lengths. As such, they can facilitate strong light-fluid interactions that are highly desirable for the development of efficient laser devices [1][2][3][4][5][6], optofluidic sensors [7,8], and nonlinear optical applications [9][10][11][12][13]. Furthermore, by integrating the microcells with telecoms fibers there is potential to exploit material properties that are unique to fluids in a compact and stable geometry for application in wide ranging areas.…”

“…Kieu et al [12,13] have developed a gap-splicing method, where the liquid is infiltrated through a glass vial positioned over the join. This approach allows for low-loss integration, though the use of a bulky liquid container negates many of the fiber benefits such as compactness and flexibility.…”

All-Fiber Optofluidic Component to Combine Light and Fluid

“…The holes in the fiber provide a natural repository for microfluidic samples, which can be employed for tuning [4], switching [5] and nonlinear optics [6], [7], for instance. The use of fibers in optofluidics is advantageous over planar geometries in two aspects.…”