scholarly journals Single-Mode Tapered Vertical SU-8 Waveguide Fabricated by E-Beam Lithography for Analyte Sensing

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3383 ◽  
Author(s):  
Yu Xin ◽  
Gregory Pandraud ◽  
Yongmeng Zhang ◽  
Paddy French
Keyword(s):  
Transmission Loss ◽  
Coupling Efficiency ◽  
Single Mode ◽  
Optical Measurements ◽  
Direct Writing ◽  
Sidewall Roughness ◽  
Scattering Loss ◽  
Waveguide Loss ◽  
One Step ◽  
Saline Solutions

In this paper, we propose a novel vertical SU-8 waveguide for evanescent analyte sensing. The waveguide is designed to possess a vertical and narrow structure to generate evanescent waves on both sides of the waveguide’s surface, aimed at increasing the sensitivity by enlarging the sensing areas. We performed simulations to monitor the influence of different parameters on the waveguide’s performance, including its height and width. E-beam lithography was used to fabricate the structure, as this one-step direct writing process enables easy, fast, and high-resolution fabrication. Furthermore, it reduces the sidewall roughness and decreases the induced scattering loss, which is a major source of waveguide loss. Couplers were added to improve the coupling efficiency and alignment tolerance, and will contribute to the feasibility of a plug-and-play optical system. Optical measurements show that the transmission loss is 1.03 ± 0.19 dB/cm. The absorption sensitivity was measured to be 4.8 dB per refractive index unit (dB/RIU) for saline solutions with various concentrations.

Fabrication, Characterization and Microsensing of Whispering-Gallery Mode Micro-Coupling Systems

2008 ◽  
Author(s):  
Qiulin Ma ◽  
Tobias Rossmann ◽  
Zhixiong Guo
Keyword(s):  
Transmission Loss ◽  
Coupling Efficiency ◽  
High Sensitivity ◽  
Single Mode ◽  
Whispering Gallery Mode ◽  
Single Mode Fiber ◽  
Whispering Gallery ◽  
Coupling System ◽  
Wide Range ◽  
Micro Sensor

An optical micro-coupling system of whispering-gallery mode usually consists of a resonator (e.g. a sphere) and a coupler (e.g. a taper). In this report, silica microspheres of 50–500 μm in diameter are fabricated by hydrogen flame fusing of an end of a single mode fiber or fiber taper. Fiber tapers are fabricated by the method of heating and pulling that meets an adiabatic condition. Taper’s waist diameter can routinely be made less than 1 μm and almost zero transmission loss in a taper is achieved which allows an effective and phase-matched coupling for a wide range sizes of microspheres. Both resonators and couplers’ surface microstructure and shapes are examined by scanning electronic microscopy. Three regimes of coupling are achieved, enabling a good flexibility to control Q value and coupling efficiency of a micro-coupling system. Whispering gallery mode shift is used to demonstrate a novel temperature micro-sensor. Its sensitivity determined from actual experimental results agrees well with the theoretical value. A concept of using the photon’s cavity ring down (CRD) in the microsphere to make a novel high-sensitivity trace gas micro-sensor is proposed. The CRD time constant when ammonia is chosen as the analyte gas is predicted using the simulated absorption lines.

Fabrication of Eyeball-Like Spherical Micro-Lens Array for Optical Fiber Coupling

2009 ◽  
Author(s):  
S. C. Shen ◽  
C. T. Pan ◽  
R. F. Shyu ◽  
C. H. Chao ◽  
J. C. Huang ◽  
...  
Keyword(s):  
Silicon Wafer ◽  
Substrate Surface ◽  
Coupling Efficiency ◽  
Numerical Aperture ◽  
Spherical Geometry ◽  
Single Mode ◽  
Batch Process ◽  
Optical Measurements ◽  
Lens Array ◽  
Micro Lens

Batch-fabrication of eyeball-like spherical micro-lens not only reduces micro assembly cost, but also replaces conventional ball-lenses or costly GRINs (Gradient Reflective Index) without sacrificing performance. Compared to the conventional micro-lenses made in a half-spherical geometry, the eyeball-like micro-lens is a sphere, which allows focusing light in all directions on the substrate surface, thus providing application flexibility for optical applications. The current eyeball-like spherical micro-lens is made using photoresist SU-8. This work develops a batch process at low temperature by spin-coating SU-8 on a surface of silicon wafer. The SU-8 thick film is patterned by UV lithography to form an array of holes for holding eyeball-like spherical micro-lens. The fabrication process employs bulk micromachining to fabricate an array of nozzles on the silicon wafer. Next, this process pours viscous SU-8 into the cavity of silicon wafer and presses it through the nozzle before reflow. The eyeball-like spherical micro-balls form by balancing between surface tension and cohesion. Varying the amount of SU-8 pressed through the nozzle controls the diameter of the balls. This paper designs a pattern with a 3 × 3 lens-array with a numerical aperture of about 0.38. Diameters range from 60 to 500 um. Optical measurements indicate a diameter fluctuation within 3% and an optical insertion loss is below 2.5dB with a wavelength of 635nm in a single-mode fiber (SMF). Therefore the eyeball-like spherical micro-lens is capable of increasing coupling efficiency.

scholarly journals Simulating the effects of refractive index difference on the coupling efficiency of periodically segmented waveguide mode converter

2021 ◽  
Vol 51 (4) ◽  
Author(s):  
Yu Zheng ◽  
Hao He ◽  
Lianqiong Jiang ◽  
Ji’an Duan
Keyword(s):  
Refractive Index ◽  
Optical Waveguides ◽  
High Efficiency ◽  
Transmission Loss ◽  
Structural Parameters ◽  
Coupling Efficiency ◽  
Single Mode ◽  
Efficient Operation ◽  
Refractive Index Difference ◽  
Efficient Coupling

Efficient coupling of micro/nano-optical waveguides with single-mode fibers is the premise for the efficient operation of the integrated photonic chip, which directly determines its optical performance. In this paper, the design principles of periodically segmented waveguide (PSW) structure used for high-efficiency fiber-chip coupling are proposed, and the effects of refractive index difference Δ on coupling efficiency and structural parameters are studied by simulation. It is found that as the Δ of the PSW increases, the period of the PSW tends to be smaller, and the coupling efficiency decreases continuously, reduced by around 0.673 dB in the range of Δ = 3% to Δ = 7%. Through the analysis of PSW optical mechanisms, it demonstrates that the main reason for the decrease of coupling efficiency is that the transmission loss of the tapered section increases sharply with the increase of Δ. High-Δ PSW is difficult to apply to highly integrated silica optical chips due to the unignorably insertion loss.

Coupling efficiency and sensitivity of an LED to a single-mode fibre

1986 ◽  
Vol 22 (21) ◽  
pp. 1110 ◽  
Author(s):  
D.N. Christodoulides ◽  
L.A. Reith ◽  
M.A. Saifi
Keyword(s):  
Coupling Efficiency ◽  
Single Mode ◽  
Single Mode Fibre ◽  
Mode Fibre

scholarly journals One-step preparation of Cr2O3-based ink with long-term dispersion stability for inkjet applications

2021 ◽  
Author(s):  
Dongjin Xie ◽  
Qiuyi Luo ◽  
Shen Zhou ◽  
Mei Zu ◽  
Haifeng Cheng
Keyword(s):  
High Precision ◽  
Inkjet Printing ◽  
Printed Electronics ◽  
Direct Writing ◽  
Deposition Technique ◽  
Functional Material ◽  
Wide Range ◽  
One Step ◽  
Oled Display

Inkjet printing of functional material has shown a wide range of application in advertzing, OLED display, printed electronics and other specialized utilities that require high-precision, mask-free, direct-writing deposition technique. Nevertheless,...

Radiation-induced transmission loss in low water peak single mode fibers

2013 ◽  
Author(s):  
Tingyun Wang ◽  
Zhongyin Xiao ◽  
Wenyun Luo ◽  
Jianxiang Wen ◽  
Jianchong Yin ◽  
...  
Keyword(s):  
Transmission Loss ◽  
Single Mode ◽  
Radiation Induced

scholarly journals Low-temperature hydrothermal synthesis of hierarchical flower-like CuB2O4 superstructures

2020 ◽  
Vol 14 (2) ◽  
pp. 113-118
Author(s):  
Daniel Ursu ◽  
Anamaria Dabici ◽  
Marinela Miclau ◽  
Nicolae Miclau
Keyword(s):  
Thermal Stability ◽  
Low Temperature ◽  
Self Assembly ◽  
Hydrothermal Solution ◽  
Optical Measurements ◽  
Oriented Attachment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
One Step

We report for the first time the fabrication of hierarchical ordered superstructure CuB2O4 with flower-like morphology via a one-step, low temperature hydrothermal method. The tetragonal structure of CuB2O4 was determined by X-ray diffraction and high-resolution transmission electron microscopy. Optical measurements attested of the quality of the fabricated CuB2O4 and high temperature X-ray diffraction confirmed its thermal stability up to 600 ?C. The oriented attachment growth and the hierarchical self-assembly of micrometer-sized platelets producing hierarchical superstructures with flower-like morphology are designed by pH of the hydrothermal solution. The excellent band gap, high thermal stability and hierarchical structure of the CuB2O4 are promising for the photovoltaic and photocatalytic applications.

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