A Formula Giving Cutoff Frequencies of Modes in an Optical Fiber Having Arbitrary Refractive-Index Profile

Kazuo HOTATE  Takanori OKOSHI  

IEICE TRANSACTIONS (1976-1990)   Vol.E62    No.1    pp.1-6
Publication Date: 1979/01/25
Online ISSN: 
Print ISSN: 0000-0000
Type of Manuscript: PAPER
Category: Optical and Quantum Electronics

Full Text: PDF(363.9KB)>>
Buy this Article

A general formula giving cutoff frequencies of modes in an optical fiber having an arbitrary refractive-index profile is derived from the stationary expression of the propagation constant. It is found that the cutoff frequency is inversely proportional to the square root of the overlap integral of the refactive-index and mode-power profiles. From this general formula, an approximate formula for actual calculation is derived, which is relatively accurate when applied to lower order modes. The single-mode condition (cutoff frequency of LP11 mode) can be calculated with a good accuracy using this approximate formula. The single-mode limits computed for some practical nonuniform-core profiles show good agreement with rigorous values.