Step-index profile

About: Step-index profile is a research topic. Over the lifetime, 3104 publications have been published within this topic receiving 53199 citations.

Low loss directional coupling between highly dissimilar optical waveguides for high refractive index integrated photonic circuits

Abstract: An optocoupler, an optical interconnect and method of manufacture providing same are provided for coupling an optical signal between a high refractive index waveguide of an integrated circuit and a waveguide external to the integrated circuit. The optocoupler includes a thinned high refractive index waveguide having a thickness configured to exhibit an effective refractive index substantially matching a refractive index of the external waveguide.

Long-period grating refractive index sensor with a modified cladding structure for large operational range and high sensitivity

Abstract: What is believed to be a novel long-period grating (LPG) refractive index sensor with a modified cladding structure is proposed and studied. In the proposed structure, the cladding of the fiber has a two-layer structure, i.e., a cladding layer of low refractive index with a reduced radius and an overlay of high refractive index. The sensitivity of the structure-modified LPG sensor to the ambient refractive index change as a function of the cladding layer and overlay parameters is investigated by way of modeling. It is found that an increase of the ambient refractive index causes a field redistribution of the cladding mode into the overlay when the parameters of the overlay are properly selected. It is shown that by reducing the radius of the cladding layer, the operational range of the LPG refractive index sensor can be as large as 0.195 (from 1.244 to 1.440) with a minimum sensitivity of 660 nm/refractive index, which represents a 31% increase of operational range in comparison with the operational range obtained from the reported structure. The design guidelines for achieving this large operation range and high sensitivity are explained by investigating the dependence of the cladding modes on the radius of the cladding layer.

Selective excitation of the LP11 mode in step index fiber using a phase mask

Abstract: We present a novel mode selective coupling technique for step index fiber. This technique utilizes phase matching for excitation of higher-order modes while suppressing the fundamental mode. Using this technique, a phase element is fabricated and tested to demonstrate the high coupling efficiency to the LP11 mode. In addition, we derive an analytical expression of the coupling efficiency of the LP11 using a single

Large effective area optical fiber

Abstract: An optical waveguide fiber having a relatively large effective area which exhibits low attenuation, low PMD and low microbending sensitivity. A step-index refractive index profile is advantageously used.

Fabry–Pérot Cavity Based on a High-Birefringent Fiber Bragg Grating for Refractive Index and Temperature Measurement

Abstract: A fiber-optic sensor for simultaneous measurement of refractive index and temperature is described. The refractive index measurement is based on the visibility variations of a Fabry-Perot interferometer. It is formed with the interfering waves generated from a low reflectivity Bragg grating inscribed on a Panda fiber and from the fiber end tip (Fresnel reflection) in contact with the liquid. The sensor is characterized by immersing the fiber tip in distilled water with different concentrations of ethylene glycol. A linear relation of the interferometer fringe visibility with refractive index variation is observed. The temperature is determined by the wavelength shift of the FBG peaks. Results show the feasibility of simultaneous measurement of refractive index and temperature and also the possibility of adjusting fringe visibility via polarization control.