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A new scheme of oriented-dependence-microlens (ODM) for lasers coupling to polarization-maintaining-fibers is demonstrated. Results showed that the ODMs enabled to visually passive alignment and packaging to achieve 80% coupling efficiency and 30-dB polarized extinction ratio.
High-quality magnetic resonance imaging and spectroscopic measurements require a highly homogeneous magnetic field. Different from global shimming, localized off-resonance can be corrected by using multi-coil shimming. Previously, integrated RF and shimming coils have been used to implement multi-coil shimming. Such coils share the same conductor for RF signal reception and shim field generation....
A direct measurement of near-field phase and intensity distribution of lensed fiber employing single-mode fiber (SMF) interferometer is proposed and demonstrated providing valuable design of micro-optic components for efficient coupling between light source and SMFs.
High-field MRI has the challenge of inhomogeneous B1+ and consequently an inhomogeneous flip angle distribution. This causes spatially dependent contrast and makes clinical diagnosis difficult. Under the small flip angle approximation and using nonlinear spatial encoding magnetic fields (SEMs), we propose a method to remap the B1+ map into a lower dimension coordinate system. Combining with RF shimming...
A method of direct measurement of near-field wavefront and intensity distribution of lensed fiber employing a single-mode fiber interferometer is proposed and demonstrated. The wavefront of lensed fiber showed a curved wave with the radius of curvatures from 8 to 32 ?m at various locations along the z axis. The wavefront radius of curvatures of laser diode and lensed fiber were in good agreement with...
A new scheme of hyperboloid microlens (HM) having precise controlling minor radius of curvature is demonstrated. The HMs exhibited high-average coupling of 83% which was better than any other grinding techniques to form asymmetric microlenses.
The characteristics of sol-gel glass phosphor have been investigated. The sol-gel glass phosphor showed 1.5% and 9.5% more efficient in quantum efficiency and luminous efficiency respectively than sintered glass phosphor.
We demonstrate a new scheme of aspherical microlens (ASM). By employing a singlestep grinding with fully automatic technique to precisely and quantitatively control the grinding offset less than 0.5 μm and minor radius of curvature within 2.4–3.5 μm, the ASMs exhibited a high-average coupling efficiency of 84.5%. This study demonstrates that the proposed ASMs through a single-step grinding technique...
High thermal stability of high-power phosphor-converted white-light-emitting diodes (PC-WLEDs) incorporating a Ce:YAG-doped glass as the phosphor layer is demonstrated. An exploring study of lumen loss, chromaticity shift, and transmittance loss of high-power PC-WLEDs with Ce:YAG-doped glass and Ce:YAG-doped silicone under thermal aging at 150°C for 500 hours was performed and compared. The results...
We demonstrate a direct near-field wavefront measurement for laser diodes employing a single-mode fiber interferometer. Detailed understanding of the near-field wavefront of laser diodes is essential for design mode matching in micro-optics coupling.
This research uses optical simulation software TracePro to analyze the effects of inner lens structure on the radiation patterns. There are three inner lens geometry parameter structure: Radius of curvature(at corner)(r), Width (w) and Height (h). This research probes into the effects of radiation pattern by changing the parameters of the radiation pattern changes with inner structure. The effect...
The high-power phosphor-based white-light-emitting diodes (LEDs) with different thicknesses and concentrations of silicone YAG phosphor after thermal aging at 150 degree C and 500 hours are studied experimentally. The results showed that the lumen loss and chromaticity (CIE) blue shift of the high-power white-light LEDs increased as the silicone YAG phosphor thickness and concentration increased....
The post-weld-shift (PWS) compensation techniques using a laser displacement meter in TO-Can and a high magnification camera in butterfly type laser-welded laser module packages are demonstrated. These techniques enable to real time quantitatively compensate the PWS induced fiber alignment shift in laser module packages
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