scholarly journals Optimized Virtual Optical Waveguides Enhance Light Throughput in Scattering Media

2021 ◽  
Author(s):  
Adithya Pediredla ◽  
Matteo Giuseppe Scopelliti ◽  
Srinivasa Narasimhan ◽  
Maysam chamanzar ◽  
Ioannis Gkioulekas
Keyword(s):  
Optical Waveguide ◽  
Optical Waveguides ◽  
Scattered Light ◽  
Mean Free Path ◽  
Scattering Media ◽  
Optical Elements ◽  
Material Parameters ◽  
Throughput Enhancement ◽  
Light Confinement ◽  
Ultrasound Parameters

Abstract Ultrasonically sculpted gradient-index optical waveguides make it possible to non-invasively steer and confine light inside scattering media. This confinement capability has applications in tissue and brain imaging, where virtual optical waveguides can be used on their own or cascaded with physical optical elements. The level of light confinement strongly depends on ultrasound parameters such as modulation pattern, frequency, and amplitude, as well as the material parameters of the scattering medium such as the refractive index, scattering coefficient, and phase function. We provide a characterization of these dependencies for a radially symmetric virtual optical waveguide. To this end, we develop a physically-accurate simulator, and use it to quantify how different ultrasound and material parameters affect light confinement. We explain our observations through a qualitative analysis of the behavior of multiply scattered light. We use the results of this analysis to demonstrate that, by properly designing ultrasound parameters, we can achieve a fourfold improvement in light confinement compared to previous virtual optical waveguide designs. We additionally show that virtual optical waveguides can achieve up to 50% light throughput enhancement compared to an ideal external lens, in a medium that mimics the scattering properties of human bladder, and at an optical thickness of one transport mean free path. Lastly, we show experimental results that corroborate the simulation predictions. In particular, we demonstrate for the first time that virtual optical waveguides effectively recycle scattered light in turbid media, and can achieve a 15% light throughput enhancement at five transport mean free paths.

scholarly journals ANALYSIS OF OPTICAL WAVEGUIDES WITH ARBITRARY INDEX PROFILE USING AN IMMERSED INTERFACE METHOD

2011 ◽  
Vol 22 (07) ◽  
pp. 687-710 ◽  
Author(s):  
THEODOROS P. HORIKIS
Keyword(s):  
Optical Waveguides ◽  
Eigenvalue Problems ◽  
Numerical Technique ◽  
Interface Problems ◽  
Index Profile ◽  
Immersed Interface Method ◽  
Immersed Interface ◽  
Light Confinement ◽  
Bragg Fibers ◽  
Matrix Eigenvalue Problems

A numerical technique is described that can efficiently compute solutions of interface problems. These are problems with data, such as the coefficients of differential equations, discontinuous or even singular across one or more interfaces. A prime example of these problems are optical waveguides, and as such the scheme is applied to Maxwell's equations as they are formulated to describe light confinement in Bragg fibers. It is based on standard finite differences appropriately modified to take into account all possible discontinuities across the waveguide's interfaces due to the change of the refractive index. Second- and fourth-order schemes are described with additional adaptations to handle matrix eigenvalue problems, demanding geometries and defects.

scholarly journals Measurements of the nonlinear refractive index in scattering media using the Scattered Light Imaging Method - SLIM

2015 ◽  
Vol 23 (15) ◽  
pp. 19512 ◽  
Author(s):  
Kelly C. Jorge ◽  
Hans A. García ◽  
Anderson M. Amaral ◽  
Albert S. Reyna ◽  
Leonardo de S. Menezes ◽  
...  
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Scattered Light ◽  
Imaging Method ◽  
Scattering Media

Process Modeling, Optimization and Characterization of Silicon Optical Waveguides by Anisotropic Wet Etching

2011 ◽  
Vol 403-408 ◽  
pp. 4295-4299
Author(s):  
H. Hazura ◽  
A.R. Hanim ◽  
B. Mardiana ◽  
Sahbudin Shaari ◽  
P.S. Menon
Keyword(s):  
Optical Waveguide ◽  
Optical Waveguides ◽  
Photonic Devices ◽  
Wet Etching ◽  
Fabrication Process ◽  
Etching Time ◽  
Optical Modulators ◽  
Silicon Waveguide ◽  
Simulation And Experiment ◽  
Silicon Based

We present a detailed fabrication process of silicon optical waveguide with a depth of 4μm via simulation and experiment. An anisotropic wet etching using Potassium Hydroxide (KOH) solutions was selected to study the influence of major fabrication parameters such as etch rate, oxidation time and development time to the fabrication performance. The fabrication of the silicon waveguide with the orientation of was modeled using ATHENA from 2D Silvaco software and was later compared with the actual fabricated device. Etching time of 4 minutes was required to etch the Si to the depth of 4μm to obtain a perfectly trapeizoidal optical waveguide structure. Our results show that the simulation model is trustworthy to predict the performance of the practical anisotropic wet etching fabrication process. The silicon-based waveguide components are targeted to be employed in realizing future photonic devices such as optical modulators.

Photoelastic Waveguides Using Strain-Compensated InAsP/InGaP Multi-Quantum-Wells

1995 ◽  
Vol 379 ◽  
Author(s):  
Q. Z. Liu ◽  
X. B. Mei ◽  
L. S. Yu ◽  
C. W. Tu ◽  
S. S. Lau
Keyword(s):  
Quantum Wells ◽  
Optical Waveguides ◽  
Intensity Ratio ◽  
Semiconductor Heterostructures ◽  
Anisotropic Property ◽  
Light Confinement ◽  
Te Mode

ABSTRACTPhotoelastic optical waveguides using strain-compensated InAsP/InGaP multiplequantum-well (MQW) have been fabricated. Lateral light confinement for waveguiding is achieved by introducing stress into semiconductor heterostructures with stable WNi surface stressor stripes. The waveguides have been characterized at both 1.52 μm and 1.32 μm wavelength in term of TE/TM intensity ratio. At 1.52 μm, the waveguides favor the propagation of TE mode, and the TE/TM intensity ratio can be as large as 15 dB. At 1.32 μm, the TE and TM intensity can be comparable. Anisotropy of waveguides fabricated along [110] or [110] directions has also been observed in term of TE/TM intensity ratio, which suggests the presence of anisotropic property of the strain-compensated MQW.

scholarly journals Fabrication of Sub-Micron Polymer Waveguides through Two-Photon Polymerization in Polydimethylsiloxane

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2485 ◽  
Author(s):  
Giulia Panusa ◽  
Ye Pu ◽  
Jieping Wang ◽  
Christophe Moser ◽  
Demetri Psaltis
Keyword(s):  
Optical Waveguides ◽  
Transmission Loss ◽  
Vital Role ◽  
Core Size ◽  
Low Loss ◽  
Two Photon ◽  
Light Confinement ◽  
Index Contrast ◽  
Controllable Fabrication ◽  
Two Photon Polymerization

Flexible ultra-compact low-loss optical waveguides play a vital role in the development of soft photonics. The search for suitable materials and innovative fabrication techniques to achieve low loss long polymer optical waveguides and interconnects has proven to be challenging. In this paper, we demonstrate the fabrication of submicron optical waveguides in polydimethylsiloxane (PDMS) using divinylbenzene (DVB) as the photopolymerizable monomer through two-photon polymerization (2PP). We show that the commercial oxime ester photoinitiator Irgacure OXE02 is suitable for triggering the DVB photopolymerization, resulting in a stable and controllable fabrication process for the fabrication of defect-free, 5-cm long waveguides. We further explore a multi-track fabrication strategy to enlarge the waveguide core size up to ~3 μm for better light confinement and reduced cross-talk. In these waveguides, we measured a refractive index contrast on the order of 0.005 and a transmission loss of 0.1 dB/cm at 710 nm wavelength.

Research on Transmission Loss of Optical Waveguide in Three-Component Acceleration Seismic Geophone

2011 ◽  
Vol 143-144 ◽  
pp. 644-648
Author(s):  
De En ◽  
Jie Yu Feng ◽  
Ning Bo Zhang ◽  
Ning Ning Wang ◽  
Xiao Bin Wang
Keyword(s):  
Production Process ◽  
Optical Waveguide ◽  
Optical Waveguides ◽  
Transmission Loss ◽  
Measurement Methods ◽  
Phase Changes ◽  
Linbo3 Crystal ◽  
Advantages And Disadvantages ◽  
Waveguide Loss ◽  
External Acceleration

The optical waveguides are produced in LiNbO3 substrate of three-component acceleration seismic geophone by lithography. Three-component acceleration seismic geophone detects changes in the external acceleration by detecting phase changes in the optical waveguides. The performance of optical waveguide directly affects the performance of three-component acceleration seismic geophone. Therefore, it is critical to measure and reduce the transmission loss of waveguides. The advantages and disadvantages of LiNbO3 crystal are introduced. The production process of Ti:LiNbO3 optical waveguide and its performance are presented. Some information about the types of transmission loss of optical waveguide and the measurement methods of optical waveguide loss are provided.

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