Claddings of optical fibers

The main application of amorphous perfluoropolymers is as cladding of optical fibers, antireflective coatings, low dielectric coatings, and in the electronic industry (e.g., photoresists)1012 and as a low-dielectric-constant insulator for high-performance interconnects.13... 

Because of their low refractive index (less than 1.43), low permeability of water and weather vapor, very low water absorption, and good adhesion to glass and optical polymers, fluoropolyurethanes are suitable for cladding of optical fibers. A variety of specialty resins are used for this purpose, which are most frequently photocurable. 

For the light guiding effect of optical fibers it is important to have a core with a refractive index somewhat larger than that of the airrounding cladding. Therefore the core normally consists of silica doped with other oxides to increase the refractive index. In the following we therefore discuss the simultaneous deposition of silica and germania in the silica tube. 

Preparation of Optical Fiber Prior to Its Use in Sensor Development De-cladding... 

There are two types of optical fibers SM and MM fibers. The important parameters characterizing fiber properties are the core and cladding indices, core diameter, attenuation ot, and numerical aperture (NA). The attenuation represents optical losses caused by absorption or scattering of light propagating through the fiber per unit length, as ... 

Optical fibers consist of a core part and a clad part. The refractive index, nh of the core is larger than the refractive index, n2, in the clad part. There are two types of optical fibers,... 

In conclusion, polymers play a versatile role in the field of chemosensors. Most interestingly, certain polymers can actively serve as sensors. This pertains to certain strongly fluorescent conjugated polymers, as pointed out above, and to polymers employed as cladding for optical fibers in evanescent wave-based sensors. Moreover, polymers are widely used as supports for transducers, which are either admixed or chemically linked to the polymer matrices. Typical examples are given in the following sections. 

An insertion guide is used to accurately locate an etched optical fiber. Fiber distal ends are chemically etched to reduce the diameter by removing fiber cladding for easier insertion into the LOG. The plastic or rubber jacket of optical fiber should be moved before this etching. One of the keys to fabrication involves accurately setting the distance from the fiber channel to the microfluidic channel shown in Fig. 1. 

The basic elements of a LIF-CPT system consist of a laser source, silica-clad silica optical fibers to conduct laser light to the sample and fluorescence to the detector, a sapphire optical window inserted into a brazed or welded channel in the push rod wall, and a detector. 

For this purpose, the system uses a Raman shifter pumped by the fourth harmonic of an Nd YAG laser to generate multiple laser beams simultaneously in the UV-visible region of the spectrum. Ten beams are separated by a set of prisms and launched into separate silica-clad silica optical fibers and delivered to the sample. Separate collection fibers deliver the fluorescent signals to specific positions on an imaging spectrographic detector. 

The basic construction of optical fibers used for telecommunications consists of a core, an integral cladding, and a protective coating. Figure 9.1 shows basic cross sections representing the two main types of optical fibers used for telecommunications. 

Cladding The layer of dielectric material that immediately surrounds the core of an optical fiber, the combination of which is fundamental to the abihty of optical fiber to guide light at certain wavelengths. The cladding material for telecommunications grade optical fibers usually consists of a silica glass that cannot be physically separated from the core. 

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