scholarly journals Numerical calculation of the light propagation in tapered optical fibers for optical neural interfaces

2021 ◽  
Author(s):  
Rosa Mach-Batlle ◽  
Marco Pisanello ◽  
Filippo Pisano ◽  
Massimo De Vittorio ◽  
Ferruccio Pisanello ◽  
...  
Keyword(s):  
Fiber Optics ◽  
Mouse Brain ◽  
Optical Fibers ◽  
Light Propagation ◽  
Cylindrical Symmetry ◽  
Neural Interfaces ◽  
Optical Systems ◽  
Computational Technique ◽  
Approaches To Study ◽  
Beam Envelope

AbstractAs implantable optical systems recently enabled new approaches to study the brain with optical radiations, tapered optical fibers emerged as promising implantable waveguides to deliver and collect light from sub-cortical structures of the mouse brain. They rely on a specific feature of multimodal fiber optics: as the waveguide narrows, the number of guided modes decreases and the radiation can gradually couple with the environment. This happens along a taper segment whose length can be tailored to match with the depth of functional structures of the mouse brain, and can extend for a few millimeters. This anatomical requirement results in optical systems with an active area very long compared to the wavelength of the light they guide and their behaviour is typically estimated by ray tracing simulations, being finite-elements methods computationally too heavy. Here we present a computational technique that exploits the beam-envelope method and the cylindrical symmetry of the fibers to provide an efficient and exact calculation of the electric field along the fibers, which may enable the design of neural interfaces optimized to meet different goals.

scholarly journals From spectral broadening to recompression: dynamics of incoherent optical waves propagating in the fiber

PhotoniX ◽  
2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Jun Ye ◽  
Xiaoya Ma ◽  
Yang Zhang ◽  
Jiangming Xu ◽  
Hanwei Zhang ◽  
...  
Keyword(s):  
Fiber Optics ◽  
Optical Fibers ◽  
Fiber Lasers ◽  
Light Propagation ◽  
Continuous Wave ◽  
Group Velocity Dispersion ◽  
Spectral Evolution ◽  
Spectral Broadening ◽  
Fundamental Research ◽  
Coherent Raman

AbstractInterplay between dispersion and nonlinearity in optical fibers is a fundamental research topic of nonlinear fiber optics. Here we numerically and experimentally investigate an incoherent continuous-wave (CW) optical field propagating in the fiber with normal dispersion, and introduce a distinctive spectral evolution that differs from the previous reports with coherent mode-locked fiber lasers and partially coherent Raman fiber lasers [Nat. Photonics 9, 608 (2015).]. We further reveal that the underlying physical mechanism is attributed to a novel interplay between group-velocity dispersion (GVD), self-phase modulation (SPM) and inverse four-wave mixing (IFWM), in which SPM and GVD are responsible for the first spectral broadening, while the following spectral recompression is due to the GVD-assisted IFWM, and the eventual stationary spectrum is owing to the dominant contribution of GVD effect. We believe this work can not only expand the light propagation in the fiber to a more general case and help advance the physical understanding of light propagation with different statistical properties, but also benefit the applications in sensing, telecommunications and fiber lasers.

scholarly journals Numerical calculation of the light propagation in tapered optical fibers for optical neural interfaces

2021 ◽  
pp. 1-1
Author(s):  
Rosa Mach Batlle ◽  
Marco Pisanello ◽  
Filippo Pisano ◽  
Massimo De Vittorio ◽  
Ferruccio Pisanello ◽  
...  
Keyword(s):  
Numerical Calculation ◽  
Optical Fibers ◽  
Light Propagation ◽  
Neural Interfaces

scholarly journals Novel Bloch wave excitation platform based on few-layer photonic crystal deposited on D-shaped optical fiber

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Esteban Gonzalez-Valencia ◽  
Ignacio Del Villar ◽  
Pedro Torres
Keyword(s):  
Optical Fibers ◽  
High Performance ◽  
Light Propagation ◽  
Fiber Optic ◽  
Layer Structure ◽  
Optical Network ◽  
Building Blocks ◽  
Bloch Wave ◽  
Nanophotonic Devices ◽  
Wide Range

AbstractWith the goal of ultimate control over the light propagation, photonic crystals currently represent the primary building blocks for novel nanophotonic devices. Bloch surface waves (BSWs) in periodic dielectric multilayer structures with a surface defect is a well-known phenomenon, which implies new opportunities for controlling the light propagation and has many applications in the physical and biological science. However, most of the reported structures based on BSWs require depositing a large number of alternating layers or exploiting a large refractive index (RI) contrast between the materials constituting the multilayer structure, thereby increasing the complexity and costs of manufacturing. The combination of fiber–optic-based platforms with nanotechnology is opening the opportunity for the development of high-performance photonic devices that enhance the light-matter interaction in a strong way compared to other optical platforms. Here, we report a BSW-supporting platform that uses geometrically modified commercial optical fibers such as D-shaped optical fibers, where a few-layer structure is deposited on its flat surface using metal oxides with a moderate difference in RI. In this novel fiber optic platform, BSWs are excited through the evanescent field of the core-guided fundamental mode, which indicates that the structure proposed here can be used as a sensing probe, along with other intrinsic properties of fiber optic sensors, as lightness, multiplexing capacity and easiness of integration in an optical network. As a demonstration, fiber optic BSW excitation is shown to be suitable for measuring RI variations. The designed structure is easy to manufacture and could be adapted to a wide range of applications in the fields of telecommunications, environment, health, and material characterization.

scholarly journals Shaping Beam Profiles Using Plastic Optical Fiber Tapers with Application to Ice Sensors

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2503
Author(s):  
Kostas Amoiropoulos ◽  
Georgia Kioselaki ◽  
Nikolaos Kourkoumelis ◽  
Aris Ikiades
Keyword(s):  
Fiber Optics ◽  
Optical Fibers ◽  
Laser Cooling ◽  
Detection Efficiency ◽  
Numerical Aperture ◽  
Beam Profile ◽  
Hollow Beam ◽  
Enhanced Sensitivity ◽  
Surface Irregularities ◽  
Plastic Optical Fibers

Using either bulk or fiber optics the profile of laser beams can be altered from Gaussian to top-hat or hollow beams allowing enhanced performance in applications like laser cooling, optical trapping, and fiber sensing. Here, we report a method based on multimode Plastic Optical Fibers (POF) long-tapers, to tweak the beam profile from near Gaussian to a hollow beam, by generating surface irregularities on the conical sections of the taper with a heat-and-pull technique. Furthermore, a cutback technique applied on long tapers expanded the output beam profile by more than twice the numerical aperture (NA) of the fiber. The enhanced sensitivity and detection efficiency of the extended profile was tested on a fiber optical ice sensor related to aviation safety.

scholarly journals Analysis of Curvature in Fiber Optic Cable for Macrobending-Based Slope Sensor

2021 ◽  
Vol 3 (1) ◽  
pp. 45-56
Author(s):  
Imam Mulyanto
Keyword(s):  
Fiber Optics ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Laser Light ◽  
Laser Intensity ◽  
Single Mode ◽  
Power Losses ◽  
Fiber Optic Cable ◽  
Power Meter ◽  
Working Principle

The analysis of fiber optics for macro bending-based slope sensors using SMF-28 single-mode optical fibers has been successfully conducted. Fiber optics were treated to silicon rubber molding and connected with laser light and power meters to measure the intensity of laser power generated. The working principle was carried out using the macrobending phenomenon on single-mode optical fibers. The intensity of laser light in fiber optic cables decreases in the event of indentation or bending of the fiber optic cable. Power losses resulting from the macrobending process can be seen in the result of the information sensitivity of fiber optics to the change of angle given. From the results of the study, the resulting fiber optic sensitivity value is -0.1534o/dBm. The larger the angle given, the lower the laser intensity received by the power meter.

Measuring floating ice thickness with optical fibers and DAS, a test case study on a frozen moutain lake.

2021 ◽  
Author(s):  
Olivier Coutant ◽  
Ludovic Moreau ◽  
Pierre Boué ◽  
Eric Larose ◽  
Arnaud Cimolino
Keyword(s):  
Fiber Optics ◽  
Optical Fibers ◽  
Ambient Noise ◽  
Seismic Waves ◽  
Safety Issue ◽  
Seismic Survey ◽  
Ice Thickness ◽  
Test Case ◽  
Monitoring Method

<p>Accurate monitoring of floating ice thickness is an important safety issue for northern countries where lakes, fjords, and coasts are covered with ice in winter, and used by people to travel. For example in Finland, 15-20 fatal accidents occur every year due to ice-related drowning. We have explored the potential of fiber optics to measure the propagation of seismic waves guided in the ice layer, in order to infer its thickness via the inversion of the dispersion curves. An optical fiber was deployed on a frozen lake at Lacs Roberts (2400m) above Grenoble and we measured with a DAS the signal generated by active sources (hammer) and ambient noise. We demonstrate that we can retrieve the ice thickness. This monitoring method could be of interest since the deployment of a fiber on ice is quite simple (e.g. using a drone) compared to other techniques for ice thickness estimation such as seismic survey or manual drilling.</p>

Imaging Spectroscopy Using Fiber Optics

1997 ◽  
Vol 3 (S2) ◽  
pp. 845-846
Author(s):  
S. Michael Angel ◽  
H. Trey Skinner ◽  
Brian J. Marquardt
Keyword(s):  
Optical Fiber ◽  
Fiber Optics ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Imaging System ◽  
Single Point ◽  
Imaging Spectroscopy ◽  
Small Diameter ◽  
Imaging Spectrometer ◽  
Remote Spectroscopy

Optical fiber probes are routinely used with optical spectrometers to allow measurements to be made on remotely located samples. In most of these systems, however, the optical fibers are used as non-imaging “light pipes” for the transmission of laser light, and luminescence or Raman signals to and from the sample. Thus, while these systems are suitable for remote spectroscopy, they are limited to single-point measurements. In a recent paper, we showed that a small-diameter (i.e., 350 μm) coherent optical fiber bundle can be combined with an AOTF-based imaging spectrometer for fluorescence and Raman spectral micro-imaging with increased flexibility in terms of sample positioning and in-situ capabilities. The previous paper described the operation of the fiber-optic microimaging probe and AOTF imaging system and showed preliminary Raman and fluorescence images for model compounds with 4 μm resolution. We have extended this work to include a discussion of the lateral and vertical spatial resolution of the fiber-optic microprobe in a non-contact proximity-focused configuration.

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