Graded-index

Graded index stmctures allow greater control over fibre characteristics. In these stmctures, the core has a variable... 

Fig. 3. Types of optical fiber (a) multimode stepped index, (b) multimode graded index, and (c) single-mode stepped index.

Fig. 6. Double crucible configuration showing core glass (upper crucible) flowing through molten cladding glass in lower crucible to yield graded-index...

Step-index Graded-index Multimode Multimode... 

Techniques for fabricating low-cost optical components such as graded index lenses, microlenses, couplers, splitters, and polarizers are needed to support optical fiber technology. Traditionally, amorphous inorganic materials have been nsed, bnt there are tremendons... 

Matejec V., Kasik I., Chomat M., Ctyroky J., Berkova D., Huttel I., Modified inverted graded-index fibers for evanescent-wave chemical sensing, Proc. SPIE 3860 (1999), Boston, pp.443-451. 

M. Chomat, D. Berkova, V. Matejec, I. Kasik, G. Kuncova, The effect of hydrodynamic conditions on the detection of aqueous solutions of toluene by means of an inverted graded-index fiber, Sensors Actuators B 2003 90 151-156. 

Figure 13. GRIN waveguide lens on SOI, consisting of a thick graded index a-SixOy layer deposited on a thin Si waveguide.

A. Delage, S. Janz, D.-X. Xu, D. Dalacu, B. Lamontagne, and A. Bogdanov, Graded-index coupler for microphotonic SOI waveguides," SPIE Proc. Vol. 5577, Photonics North 2004 (in press, 2004). 

M. D. Felt, and J. A. Fleck, Light propagation in graded-index optical fibers, Applied Optics 17, 3990-3998 (1978). 

Figure 6.102 Schematic illustration of (a) step-index, (b) graded-index, and (c) single-mode optical fibers. Reprinted, by permission, from J. F. Shackelford, Introduction to Materials Science for Engineers, 5th ed., p. 611. Copyright 2000 by Prentice-Hall, Inc.

Single-mode fibers have many advantages over multimode fibers. See Fig. 3. Compared to the 50 or 62.5 micron core diameter of typical graded-index multimode fibers, some single-mode fibers have a core diameter near... 

The agglomerating index is a grading index based on the nature of the residue from a 1-g sample of coal when heated at 950 20°C (1740 35°F) in volatile matter determination (ASTM D-3175). 

Palais, J.C., (1980), Fiber coupling using graded-index rod lenses , Appl. Optics., 19(12), 2011-2018. 

Both step index and graded index fibers have been prepared by this process, using Ge02 und B203 as dopant materials. Deposition efficiencies of about 45% have been obtained. The deposition rate is typically between 0.4—1.6 g/min and blanks yielding 10 km fibers have been made. 

Figure 14b displays a graded index profile which was produced by the deposition of 2000 layers. Because of the thinness of the layers they can no longer be detected individually. For both preforms the germanium depletion in the center is obvious from the circular interference lines. 

Fig. 17. Cross section of a fluorine doped graded index fiber etched with dilute HF14. Graded core of 35 pm diameter. (Reproduced by permission of The Electrochemical Society)...

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