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.

Fabrication of Lensed Plastic Optical Fiber Array Using Electrostatic Force

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Yih-Tun Tseng ◽  
Jhong-Bin Huang ◽  
Che-Hsin Lin ◽  
Chin-Lung Chen ◽  
Wood-Hi Cheng
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Electrostatic Force ◽  
Coupling Efficiency ◽  
Numerical Aperture ◽  
Uv Curing ◽  
Power Budget ◽  
Fiber Array ◽  
Plastic Optical Fibers ◽  
Efficient Coupling

The GI (graded-index) POFs (Plastic optical fibers), which has been proven to reach distances as long as 1 km at 1.25 Gb/s has a relatively low numerical aperture . Therefore, the efficient coupling of GI POFs to the light source has become critical to the power budget in the system. Efficient coupling for a POFs system normally involves either a separate lens or the direct formation of the lens at the end of the fiber. Forming the lens-like structure directly on the fiber end is preferred for simplicity of fabrication and packaging, such as polishing and fusion, combine different fibers with the cascaded fiber method and hydroflouride (HF) chemical etching. These approaches are well established, but applicable only to glass. Optical assembly architecture for multichannel fibers and optical devices is critical to optical fiber interconnections. Multichannel fiber-pigtail laser diode (LD) modules have potential for supporting higher data throughput and longer transmission distances. However, to be of practical use, these modules must be more precise. This work proposes and manufactures lensed plastic optical fibers (LPOF) array. This novel manipulation can be utilized to fabricate an aspherical lens on a fiber array after the UV curing of the photo-sensitive polymer; the coupling efficiency (CE) is increased and exceeds 47% between the LD array and the fiber array.

scholarly journals Dynamically controlled light delivery over large brain volumes through tapered optical fibers

2016 ◽  
Author(s):  
Ferruccio Pisanello ◽  
Gil Mandelbaum ◽  
Marco Pisanello ◽  
Ian A. Oldenburg ◽  
Leonardo Sileo ◽  
...  
Keyword(s):  
Fiber Optics ◽  
Optical Fibers ◽  
Light Emission ◽  
Motor Behavior ◽  
Numerical Aperture ◽  
Brain Volumes ◽  
Light Emitting ◽  
Precise Control ◽  
Neural Processes ◽  
Large Brain

ABSTRACTOptogenetics promises spatiotemporal precise control of neural processes using light. However, the spatial extent of illumination within the brain is difficult to control and cannot be adjusted using standard fiber optics. We demonstrate that optical fibers with tapered tips can be used to illuminate either large brain volumes or dynamically selectable subregions. Remotely adjusting the light input angle to the fiber varies the light-emitting portion of the taper over several millimeters without movement of the implant. We use this mode to activate dorsal versus ventral striatum of individual mice and reveal different effects of each manipulation on motor behavior. Conversely injecting light over the full numerical aperture of the fiber results in light emission from the entire taper surface, achieving broader and more efficient optogenetic activation of neurons when compared to the standard flat-faced fiber stimulation. Thus, tapered fibers permit focal or broad illumination that can be precisely and dynamically matched to experimental needs.

Investigation of influence of tilt angle on mode dispersion in step-index plastic optical fibers

2011 ◽  
Vol 19 (1) ◽  
Author(s):  
M.S. Kovacevic ◽  
A. Djordjevich
Keyword(s):  
Optical Fibers ◽  
Tilt Angle ◽  
Functional Relationship ◽  
Numerical Aperture ◽  
Fiber Axis ◽  
Step Index ◽  
Mode Dispersion ◽  
Plastic Optical Fibers ◽  
Spectroscopic Sensors ◽  
First Time

AbstractEffect of numerical aperture on mode dispersion and bandwidth is reported for commercially available step-index plastic optical fibers. For the first time, the functional relationship is given between dispersion and the “tilt-angle” describing the slant of the input/output face for a fiber terminated by a plane not perpendicular to the fiber axis. This tilt of a non-squarely terminated fiber may be intentional as in some biomedical spectroscopic sensors, or otherwise when exploiting the quick-interconnectivity potential of plastic fibers.

Mode coupling contribution to radiation losses in curvatures for high and low numerical aperture plastic optical fibers

2002 ◽  
Vol 20 (7) ◽  
pp. 1160-1164 ◽  
Author(s):  
M.A. Losada ◽  
I. Garces ◽  
J. Mateo ◽  
I. Salinas ◽  
J. Lou ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Mode Coupling ◽  
Numerical Aperture ◽  
Radiation Losses ◽  
Plastic Optical Fibers

Frequency response and bandwidth in low-numerical-aperture step-index plastic optical fibers

2014 ◽  
Vol 53 (30) ◽  
pp. 6999 ◽  
Author(s):  
Svetislav Savović ◽  
Branko Drljača ◽  
Milan S. Kovačević ◽  
Alexandar Djordjevich ◽  
Jovan S. Bajić ◽  
...  
Keyword(s):  
Frequency Response ◽  
Optical Fibers ◽  
Numerical Aperture ◽  
Step Index ◽  
Plastic Optical Fibers

Signal Processing Enhanced Fiber Vibration Sensors

2013 ◽  
Vol 543 ◽  
pp. 302-305
Author(s):  
Daniele Tosi ◽  
Massimo Olivero ◽  
Alberto Vallan ◽  
Guido Perrone
Keyword(s):  
Signal Processing ◽  
Optical Fibers ◽  
Adaptive Filters ◽  
Spectral Estimation ◽  
Cost Effective ◽  
Fiber Sensors ◽  
High Frequencies ◽  
Vibration Sensors ◽  
Signal Processing Algorithms ◽  
Plastic Optical Fibers

The paper analyzes the feasibility of cost-effective fiber sensors for the measurement of small vibrations, from low to medium-high frequencies, in which the complexity of the measurement is moved from expensive optics to cheap electronics without losing too much performance thanks to signal processing algorithms. Two optical approaches are considered: Bragg gratings in standard telecom fibers, which represent the most common type of commercial fiber sensors, and specifically developed sensors made with plastic optical fibers. In both cases, to keep the overall cost low, vibrations are converted into variations of the light intensity, although this makes the received signal more sensitive to noise. Then, adaptive filters and advanced spectral estimation techniques are used to mitigate noise and improve the sensitivity. Preliminary results have demonstrated that the combined effect of these techniques can yield to a signal-to-noise improvement of about 30 dB, bringing the proposed approaches to the level of the most performing sensors for the measurement of vibrations.

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