Search Results (3)

Hyperparametric oscillation is essential for coherent optical signal generation in a broad wavelength range. Integration in a compact system, such a broadband light source, is of special interest for practical applications requiring field-deployable spectroscopy devices. Here we demonstrate an all-fiber hyperparametric oscillation source based on four-wave mixing in a high-Q fiber Fabry–Pérot (FFP) microresonator. Assisted by the Raman effect, the generated optical signal spans over 400 nm with fine line-to-line spacing of 667 MHz. The compatibility of this FFP microresonator enables a robust and reliable all-fiber system through a splicing technique and fiber connectors. Such a plug-and-play platform is convenient and efficient for broad applications in optical communications and spectroscopy. Full article

Hollow core microbubble structures are good candidates for the construction of high performance whispering gallery microresonator and Fabry-Perot (FP) interference devices. In the previous reports, most of interest was just focused on the dual-ended microbubble, but not single-ended microbubble, which could be used for tip sensing or other special areas. The thickness, symmetry and uniformity of the single-ended microbubble in previous reports were far from idealization. Thus, a new ultra-thin single-ended spherical microbubble based on the improved critical-state pressure-assisted arc discharge method was proposed and fabricated firstly in this paper, which was fabricated simply by using a commercial fusion splicer. The improvement to former paper was using weak discharge and releasing pressure gradually during the discharging process. Thus, the negative influence of gravity towards bubble deformation was decreased, and the fabricated microbubble structure had a thin, smooth and uniform surface. By changing the arc discharge parameters and the fiber position, the wall thicknesses of the fabricated microbubble could reach the level of 2 μm or less. The fiber Fabry-Perot (FP) interference technique was also used to analyze the deformation characteristic of microbubble under difference filling pressures. Finding the ends of the microbubbles had a trend of elongation with axial compression when the filling pressure was increasing. Its sensitivity to the inner pressure of microbubble samples was about ~556 nm/MPa, the bubble wall thickness was only of about 2 μm. Besides, a high whispering gallery mode (WGM) quality factor that up to 10⁷ was realized by using this microbubble-based resonator. To explain the upper phenomenon, the microbubble was modeled and simulated with the ANSYS software. Results of this study could be useful for developing new single-ended whispering gallery mode micro-cavity structure, pressure sensors, etc. Full article

A micro-optical Fabry–Perot cavity fabricated by non-linear laser lithography on the endface of a standard telecom fiber is tested here as a microsensor for identifying oily liquids. The device operates within the 1550 nm spectral region, while the spectra recorded in reflection mode correlate to the refractive index of the oily liquids used, as well as, to the diffusion dynamics in the time domain of the oily samples inside the porous photo-polymerized sensing head. The operation of the microresonator sensing probe is explained by using a three-layer Fabry–Perot model and basic diffusion physics to estimate diffusivities for three series of refractive index matching oils with different chemical compositions that had been used in those experiments. The distinct spectro-temporal response of this sensing probe to the different oil samples is demonstrated and discussed. Full article