# What is Single mode: Definition and 11 Discussions

A transverse mode of electromagnetic radiation is a particular electromagnetic field pattern of the radiation in the plane perpendicular (i.e., transverse) to the radiation's propagation direction. Transverse modes occur in radio waves and microwaves confined to a waveguide, and also in light waves in an optical fiber and in a laser's optical resonator.Transverse modes occur because of boundary conditions imposed on the wave by the waveguide. For example, a radio wave in a hollow metal waveguide must have zero tangential electric field amplitude at the walls of the waveguide, so the transverse pattern of the electric field of waves is restricted to those that fit between the walls. For this reason, the modes supported by a waveguide are quantized. The allowed modes can be found by solving Maxwell's equations for the boundary conditions of a given waveguide.

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1. ### I Phonon Number Conservation in a Single Mode Oscillation Experiment

Suppose I prepare an experiment where I excite a single mode of oscillation of the lattice, that is something like ##u(x, t) = Ae^{i(kx-\omega t)} ## (in the classical limit). The energy corresponding to that mode should be ##E = \frac 1 2 \rho L^3 A^2 \omega^2 ##. If I equate this equation to...
2. ### Fibre attenuation with absoring cladding

Homework Statement Given a single mode fibre with non-absorbing core and absorbing cladding where the power propagating in the fundamental mode is split 70%:30% between core and cladding, calculate overall attenuation of the mode along the fibre in dB/km at 1550nm source wavelength where the...
3. ### How Does Statistical Mechanics Predict the Expectation Value in Quantum States?

Homework Statement I am having trouble connecting the expectation value of ##\hat a^\dagger \hat a## to the prediction from statistical mechanics for the state $$\hat \rho = \sum_n \frac{\bar n^n}{(1 + \bar n)^{n+1}} |n\rangle \langle n|$$ Homework EquationsThe Attempt at a Solution [/B]...
4. ### I Transmission in Single Mode Waveguide

Hello there, I was wondering if the power profile of a single mode waveguide can be changed? I mean, a wave that travels through the waveguide will have a harmonic shape, right? Is it possible to get a different shape of the power profile? Thank you :)
5. ### How does Total Internal Reflection in a mm/sm fiber work?

I know Snell's Law and I do understand that there are single and multimode fibers. A fiber carries light hence to total internal reflection. so far so good. But is it only a single mode fibre that works with total internal reflection? And if so, how does the multimode fibre carry light then?
6. ### What Type of Lens Should I Choose for Single Mode Fiber Coupling?

Hello What kind of lens (focal length and numerical apper.) i should choose to couple light ( wave length 1565nm, beam diameter 2mm, M-square>1) to a single mode fiber (core diameter 8 microns, mode field diameter 10 microns and NA=0.14)? Any thoughts Thank you
7. ### Why do we aim for Single Mode waveguides?

I trying to formulate a new project based on waveguides (~1 cm long) for sensing with the evanescent field. In all papers I've seen on similar topics they all aim for single mode (SM) waveguides, but I never understood the reason. Is there a quick answer?
8. ### Divergence angle of light exiting a nano-etched single mode fiber

I am working with a single mode fiber at 830 nm with a NA of 0.12 (http://www.thorlabs.com/thorcat/19600/P3-830A-FC-2-AutoCADPDF.pdf). One end has a fiber tip coated in silver with a small hole of 200 nm diameter to essentially create a point source. My advisor told me that the fiber has a few...
9. ### Exploring Fibre Optic Bandwidth & Single Mode

It's given, "fibre optics are thin to accommodate single electromagnetic mode" what do they mean by single electromagnetic mode...? And also mentioned it has high bandwidth, i know that bandwidth is difference of highest and lowest frequencies of the signal. So if fibre optics has high...
10. ### Single Mode to Multi-mode back to Single Mode

Alright. I'm having a little trouble getting started on this design of an interferometer. Essentially what I want is to couple a laser into the single mode fiber (SMF), which is fusion spliced to a multi-mode fiber (MMF). Assuming the fiber is unperturbed, the modes will not mix and you will no...
11. ### Maximun bps rate on an ITU channel over standard single mode fiber

I have to find the maximun bps that it can be reach using a point-to-point link of 40 km long of optic fiber. I use an ITU normalized channel (100 GHz optic BW). So, I can choose any electric modulation and any optic modulation, too. Anybody could help me? Any answer is welcome. Thanks.