Coupling efficiency of two anisotropic single-mode slab waveguides butt-joined via a gap

1994 ◽  
Vol 77 (2) ◽  
pp. 20-28
Author(s):  
Shinnosuke Sawa ◽  
Toshio Masuchi
1992 ◽  
Vol 40 (2) ◽  
pp. 338-345 ◽  
Author(s):  
S. Sawa ◽  
M. Geshiro ◽  
M. Hotta ◽  
H. Kanetake

1986 ◽  
Vol 22 (21) ◽  
pp. 1110 ◽  
Author(s):  
D.N. Christodoulides ◽  
L.A. Reith ◽  
M.A. Saifi

2020 ◽  
Vol 49 (12) ◽  
pp. 20201049-20201049
Author(s):  
蔺淑琴 Shuqin Lin ◽  
张继前 Jiqian Zhang ◽  
朱新蕾 Xinlei Zhu ◽  
王飞 Fei Wang ◽  
蔡阳健 Yangjian Cai ◽  
...  

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3383 ◽  
Author(s):  
Yu Xin ◽  
Gregory Pandraud ◽  
Yongmeng Zhang ◽  
Paddy French

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.


Author(s):  
Qiulin Ma ◽  
Tobias Rossmann ◽  
Zhixiong Guo

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.


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