RP Photonics logo
RP Photonics
Encyclopedia
Consulting Software Encyclopedia Buyer's Guide

Short address: rpp-con.com

Dr. Paschotta, the founder of RP Photonics, supports your R & D with his deep expertise. Save time and money with efficient support!

Short address: rpp-soft.com

Powerful simulation software for fiber lasers and amplifiers, resonator design, pulse propagation and multilayer coating design.

Short address: rpp-enc.com

The famous Encyclopedia of Laser Physics and Technology provides a wealth of high-quality scientific and technical information.

Short address: rpp-bg.com

In the RP Photonics Buyer's Guide, you easily find suppliers for photo­nics products. As a supp­lier, you can profit from enhanced entries!

Learn on lasers and photonics every day!
VL logo part of the
Virtual
Library

Mode Coupling

<<<  |  >>>  |  Feedback

Buyer's Guide

Use the RP Photonics Buyer's Guide to find suppliers for photonics products! You will hardly find a more convenient resource.

Ask RP Photonics for advice based on numerical simulations, e.g. of mode coupling phenomena in photonic devices.

Definition: a concept for describing and calculating light propagation in certain situations, e.g. involving nonlinear interactions

German: Modenkopplung, Kopplung zwischen Moden

Categories: fiber optics and waveguides, methods

How to cite the article; suggest additional literature

The concept of mode coupling is very often used e.g. to describe the propagation of light in some waveguides or optical cavities under the influence of additional effects, such as external disturbances or nonlinear interactions. The basic idea of coupled-mode theory is to decompose all propagating light into the known modes of the undisturbed device, and then to calculate how these modes are coupled with each other by some additional influence. This approach is often technically and conceptually much more convenient than, e.g., recalculating the propagation modes for the actual situation in which light propagates in the device.

Some examples of mode coupling are discussed in the following:

Technically, the mode coupling approach is often used in the form of coupled differential equations for the complex excitation amplitudes of all the involved modes. These equations contain coupling coefficients, which are usually calculated from overlap integrals, involving the two mode functions and the disturbance causing the coupling. Typically, the applied procedure is first to calculate the mode amplitudes for the given light input, then to propagate these amplitudes based on the above-mentioned coupled differential equations (e.g. using some Runge–Kutta algorithm), and finally (if required) to recombine the mode fields to obtain the resulting field distribution.

An important physical aspect of such coherent mode coupling phenomena is that the optical power transferred between two modes depends on the amplitudes which are already in both modes. A consequence of that is that the power transfer from a mode A to another mode B can be kept very small simply by strongly attenuating mode B. In this way, mode B is prevented from acquiring sufficient power to extract power from mode A efficiently, so that mode A experiences only little loss, despite the coupling.

Bibliography

[1]A. W. Snyder, “Coupled-mode theory for optical fibers”, J. Opt. Soc. Am. 62 (11), 1267 (1972)
[2]H. Kogelnik and C. V. Shank, “Coupled-wave theory of distributed feedback lasers”, J. Appl. Phys. 43 (5), 2327 (1972)
[3]A. Yariv, “Coupled-mode theory for guided-wave optics”, IEEE J. Quantum Electron. QE-9, 919 (1973)
[4]H. Haus et al., “Coupled-mode theory of optical waveguides”, J. Lightwave Technol. 5 (1), 16 (1987)
[5]W. P. Huang et al., “Optical wavelength filter with tapered couplers”, IEEE Photon. Technol. Lett. 3 (9), 812 (1991)
[6]R. Paschotta et al., “Nonlinear mode coupling in doubly-resonant frequency doublers”, Appl. Phys. B 58, 117 (1994)
[7]W.-P. Huang, “Coupled-mode theory for coupled optical waveguides: an overview”, J. Opt. Soc. Am. A 11 (3), 963 (1994)
[8]N. Matuschek et al., “Exact coupled-mode theories for multilayer interference coatings with arbitrarily strong index modulations”, IEEE J. Quantum Electron. 33 (3), 295 (1997)
[9]R. Paschotta, “Beam quality deterioration of lasers caused by intracavity beam distortions”, Opt. Express 14 (13), 6069 (2006)
[10]A. V. Smith and J. J. Smith, “Mode instability in high power fiber amplifiers”, Opt. Express 19 (11), 10180 (2011)
[11]A. W. Snyder and J. D. Love, Optical Waveguide Theory, Chapman and Hall, London (1983)

(Suggest additional literature!)

See also: modes, fibers, waveguides

How do you rate this article?

Your general impression: don't know poor satisfactory good excellent
Technical quality: don't know poor satisfactory good excellent
Usefulness: don't know poor satisfactory good excellent
Readability: don't know poor satisfactory good excellent
Comments:

Found any errors? Suggestions for improvements? Do you know a better web page on this topic?

Spam protection: (enter the value of 5 + 8 in this field!)

If you want a response, you may leave your e-mail address in the comments field, or directly send an e-mail.

If you like our website, you may also want to get our newsletters!

arrow

Fiber Optics Software

RP Fiber Calculator software

RP Fiber Calculator – a convenient tool for calculations on optical fibers:

mode profiles

screen shot

The basic version of this software is offered for free!

– Show all banners –

– Get your own banner! –