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Equilibrium mode distribution

About: Equilibrium mode distribution is a research topic. Over the lifetime, 928 publications have been published within this topic receiving 14939 citations.


Papers
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Patent
19 Jul 1991
TL;DR: In this paper, a wavelength selective structure is coupled to an adiabatic Y-coupler via a multimode section which supports both symmetric and antisymmetric modes.
Abstract: A wavelength selective structure is coupled to an adiabatic Y-coupler via a multimode section which supports both symmetric and antisymmetric modes. One single mode branch of the coupler converts guided light to a symmetric mode, whereas the other single mode branch converts guided light to an anti-symmetric mode. The structure, which includes a pair of single mode waveguide arms coupled to the common section and a reflection device (such as a grating or ROR) located in each arm, converts reflected light from a symmetric mode to an anti-symmetric mode and conversely. Applications described include a channel dropping filter and channel balancing apparatus for WDM systems, and a dispersion compensator for fiber optic systems.

57 citations

Journal ArticleDOI
TL;DR: It is found that the first higher-order mode under the condition near cut-off rapidly attenuates because of waveguide imperfections, in which the loss due to core-cladding boundary distortions is the most dominant.
Abstract: A new technique has been proposed for direct measurement of the cut-off wavelength, at which the first higher-order mode disappears. It uses a change of a near-field pattern of a fiber, which is excited by a variable wavelength source. The cut-off wavelength can be measured with +/-5-nm accuracy. The most suitable fiber length for precise measurement is 10-20 mm. It is found, furthermore, that the first higher-order mode under the condition near cut-off rapidly attenuates because of waveguide imperfections, in which the loss due to core-cladding boundary distortions is the most dominant.

56 citations

Journal ArticleDOI
TL;DR: In this paper, the reflection of a guided mode obliquely incident to a periodic, shallow, surface corrugation, waveguide grating is analyzed using the local normal mode expansion of coupled-mode theory.
Abstract: The reflection of a guided mode obliquely incident to a periodic, shallow, surface corrugation, waveguide grating is analyzed using the local normal mode expansion of coupled-mode theory. The coupling coefficients which give the strength of the TE-TE, TE-TM, TM-TE, and TM-TM mode interactions are evaluated as a function of incidence angle. The results are compared to the coupling coefficients obtained using a number of other analytical techniques. >

55 citations

Journal ArticleDOI
TL;DR: It is demonstrated that the nondestructive measurement of mode coupling along a few-mode fiber using a synchronous multi-channel OTDR with a 10-m spatial resolution is successfully obtained.
Abstract: We describe the nondestructive measurement of mode coupling along a few-mode fiber using a synchronous multi-channel optical time-domain reflectometer (OTDR). By installing a few-mode fiber (FMF) coupler made with a phase mask method, we excite the LP01 mode in an FMF under the test as an input mode, and then we detect backward Rayleigh scattered LP11a or LP11b modes, which were generated as a result of the mode coupling through the coupler. The mode coupling distribution between the LP01 and LP11a,b modes along the test FMF was successfully measured with a 10-m spatial resolution by obtaining the ratio between the backscattered LP01 mode and LP11a or LP11b. The value of the mode coupling obtained with the present method agreed well with that obtained with the conventional transmission method.

55 citations

Journal ArticleDOI
TL;DR: In this paper, a vertically asymmetric coupler was proposed to transfer broadband light from a singlemode optical fiber to a single-mode high-index contrast waveguide on a silicon substrate.
Abstract: A coupler to efficiently transfer broadband light from a single-mode optical fiber to a single-mode high-index contrast waveguide has been fabricated on a silicon substrate. We utilized a novel coupling scheme, with a vertically asymmetric design consisting of a stepwise parabolic graded index profile combined with a horizontal taper, to simultaneously confine light in both directions. Coupling efficiency has been measured as a function of the device dimensions. The optimal coupling efficiency is achieved for structures whose length equals the focal distance of the graded index and whose input width is close to the mode field diameter of the fiber. The fabricated structure is compact, robust and highly efficient, with an insertion loss of 2.2dB at 1550nm. The coupler exhibits less than 1dB variation in coupling efficiency in the measured spectral range from 1520nmto1620nm. The lowest insertion loss of 1.9dB is measured at 1540nm. The coupler design offers highly efficient coupling for single mode waveguid...

54 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20235
202212
20218
20205
20191
20183