CO 2 laser processing offers the possibility to inscribe structures within glass-clad SiGe-core fibers by altering the spatial distribution of the Si and Ge. Spatial segregation of Ge to the end of a fiber is shown via optical transmission measurements used to alter the local bandgap, and the curved end of the fiber focuses the output of a multimode fiber. Scalable fabrication is demonstrated using a commercial CO 2 laser engraver for processing of arrays.

CO 2 laser annealing of SiGe core, glass-clad optical fibers is a powerful technique for the production of single-crystal cores with spatially varying Ge concentrations. Laser power, laser scan speed and cooling air flow alter the Ge distribution during annealing. In this work, near-single crystal fibers exhibiting a central axial feature with peak Ge concentration ∼15 at% higher than the exterior of the semiconductor core have been prepared. Preferential transmission of near infrared radiation through the Ge-rich region, and spectral data confirm its role as a waveguide within the semiconductor core. This proof-of-concept step toward crystalline double-clad structures is an important advancement in semiconductor core optical fibers made using the scalable molten core method.

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A new system on demodulation of distributed fiber Bragg grating (FBG) sensor is built which is based on Whispering Gallery Modes Optical Microcavities. In order to eliminate the temperature effect on strian measurement two adjacent FBGs (one for sensing, the other for reference) with similar central wavelength and different lengths as a probe by parallel connection are utilized. Studies have shown that the Whispering Gallery Mode Optical Microcavities with special properties of selecting specific light, when the light couple into the cavity and shocking back and forth, only the specific light can couple out, it can be expressed as: 2πrn = kλ, where r is the cavity radius, n is the refractive index of the cavity, λ is the wavelength of the light coupled out, k is taken a positive integer. Using the fature of Whispering Gallery Modes Optical Microcavities to demodulate the spectral signal of the sensing probe, Combined with the light detector, signal amplifiers, computers and other devices to dispaly the detected strain in real time. Experiment result shows that it is feasible to demodulate action spectrum and the cross of FBG for temperature and the strain is solved. It is testified that the initial establishment of the laboratory system is stable, reliable, and less expensive.

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