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Questions tagged [waveguide]

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What is air band and band gap in Photonic crystal structure?

want to know the meaning of air band of photonic crytal
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15 views

what is bolch optical mode?

I have read some papers(https://arxiv.org/ftp/arxiv/papers/1206/1206.4342.pdf) where the word ''bolch mode'' used. Now I want to know what kind of optical mode this is and how or why it is generated?
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Number of TM Modes in Waveguide in MIM waveguide

I'm working on a practice question requiring me to find the total number of TM modes (including normal modes and SPP excitation modes) in a symmetric Metal-Insulator-Metal (MIM) waveguide only knowing ...
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12 views

Comparision of using two dimensional mode or one dimensional in case of optical data transmission

Many works have been done to increase capacity of optical communication. I saw that some researcher using 1-D mode ,some 2-D to implement their device.The reson of using 1-d/2-d beacuse of their types ...
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1answer
15 views

What is the relationship of optical mode and data?

This question is on the plot of mode division multiplexing system where it is said capacity crunch can be solved using mdm technique. Now, we know single mode fiber can transmit upto 1Tbps. Now if i ...
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40 views

Can I couple 1064 nm and its harmonic 532 nm in a single polarization maintaining fiber?

I have an experiment where I need to get a largish (40 mW) amount of 532 nm light and small amount (<50 µW) of 1064 nm light into a device under test. I need something with stable polarization so ...
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14 views

Why -20dB is taken as the standard rejection ratio for optical mode rejection in multimode waveguide?

In case of multimode waveguide to demonstrate perfect mode rejection, I saw researchers use boundary of -20dB. If mode power at output is less then -20dB, it is considered as fully rejected/filter out....
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33 views

What causes the upper limit on wavelength in optical fiber?

It's well known that a most given waveguide modes have a cutoff wavelength above which the mode is no longer supported. At low wavelengths, more modes are supported. But what happens at high ...
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27 views

How to measure wave vector from complex pressure?

I want to plot the dispersion relation in comsol for an acoustic waveguide. I am working in pressure acoustics, so my dependent variable is pressure. Comsol treats pressure as a complex number. How ...
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1answer
28 views

Waveguide wave equation

Consider a wave guide built from two parallel slabs at $x=0, x=L$. between the slabs there is a dielectric material with $\mu=\epsilon=1$ and electric conductivity with a frequency of $\sigma(\omega)=\...
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12 views

Transfer of momentum from a wave to it’s waveguide based on theta and the inertia of the wave?

Bit of a complicated one - I've been trying to understand how the energy in a wave dissipates or transfers it's energy to the walls of a wave guide as the angle of the wave guide changes. As the ...
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1answer
19 views

Frequency response of the waveguide

So, I have signal in the waveguide that is transmitted by two modes of radiation, for which the delay is for example $τ1 = 6ns$, $τ2 = 6.5ns$, respectively. And the energy supplied to the receiver by ...
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69 views

Leaky waveguide - calculating the frequency [closed]

The figure shows a waveguide with a square cross-section. The length of the side of the cross-section is $a = 3.5$ . A TE wave with a frequency f propagates in the waveguide in the positive direction ...
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1answer
36 views

Why does TEM mode not propagate in single conductor system?

In the Wikipedia article it is said: "In hollow waveguides (single conductor), TEM waves are not possible, since Maxwell's Equations will give that the electric field must then have zero divergence ...
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58 views

Using convolution to simulate acoustic dispersion in shallow water

Background I'm a marine biologist who's trying to wrap my head around shallow water propagation. I'm interested in how acoustic dispersion (as described by Pekeris' waveguide) alters how sounds ...
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23 views

what is the advantages of using 2-μm operating wavelength light in sdm/mdm technology? [closed]

Most of the work have been done in the communication band but recently there has been emerging interest in extending the operating wavelength of communication system to the short-wave infrared (2 μm). ...
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1answer
228 views

what is effective index method which is used to solve modes in rectangular waveguide? [closed]

I actually want to know the basics of effective index methods for solving the optical modes in slab/rectangular waveguides.
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1answer
46 views

Which wave is widely used in waveguides?

I've studied that the rectangular waveguides are widely used because they have less cut-off frequency and as we know that the cut-off frequency is one of the major factors for waveguides. The article ...
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2answers
29 views

Does the electromagnetic wave inside a waveguide experience matter wave behavior?

The electromagnetic wave inside a wave-guide has a longitudinal component besides the transverse one. Does this imply it has an effective mass? It is shown to do so by Wang in https://arxiv.org/ftp/...
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1answer
73 views

Noise covariance matrix

I've been trying to understand this paper. The paper seems to be about analyzing noise properties of a superconducting coplanar waveguide microwave resonator. They use an IQ mixer to perform ...
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2answers
138 views

What is a leaky mode of a waveguide?

I know that in a waveguide is possible to distinguish between guided modes and radiative modes. For example, in a planar waveguide, a guided mode is oscillatory inside the core and vanishes ...
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1answer
64 views

Dielectric Slab Waveguide

I have a question about dielectric slab waveguides. In these type of waveguides, n1>n2. What would happen in the case of n2>n1? I think there would be no propogation through the waveguide, but I am ...
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75 views

Input impedance of a line with complex load

I am currently studying electromagnetism mostly with the help of the book "Microwave Engineering" and when trying to solve problems which main goal is to compute the input impedance of a lossless ...
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68 views

Physical origin of transverse waveguide modes

I've been working with multimode lasers for a couple of months now, and whilst I have a good understanding of what their output looks like and what longitudinal modes are, I continue to be absolutely ...
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1answer
527 views

Why are TM_10 modes not possible in a non-magnetic waveguide?

In a hollow rectangular waveguide, we may either propagate transverse electric modes (TE$_{mn}$) where we have electric standing waves quantified by m and n in each direction, or transverse magnetic ...
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1answer
98 views

Why are electromagnetic fields in free space (isotropic and homogeneous) constant over all time and space?

I see very often that electric and magnetic fields ($\mathbb{R}^3$) in free space are assumed to have the form: $$\vec{E}=\vec{E}_0{(x,y)}\exp{[i(wt-kz)]}$$ $$\vec{H}=\vec{H}_0{(x,y)}\exp{[i(wt-kz)]}$...
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1answer
209 views

Evanescent waves and “phase-matching” argument

I have looked through several Classical ED approaches to introduce evanescent waves, but still can't build the connections. I was told that evanescent waves are needed to satisfy boundary conditions ...
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1answer
60 views

Infinitely circling ray! (solving the eikonal equation in polar coordinates) - can I think of this in terms of waveguides? [closed]

In short: I want to know the necessary conditions in order for a ray to 'bend backwards' and complete a full circle. In detail: Suppose theres a medium with a radially symmetric index of ...
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1answer
92 views

Finding the resonant frequency of a rectangular resonator filled with a magnetic material

The prompt is to find the resonant frequency $f_r$ of a rectangular resonator which is filled with a magnetic material rather than standard air or vacuum. I'm confused as how the resonance frequency ...
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2answers
58 views

Confusion between a signal sent at a given frequency and the Fourier components?

I have been reading about phase and group velocity (maybe the context will be useful here) and was attempting a question when I became rather stumped. The question was Square pulses are sent along ...
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0answers
26 views

Why does the fundamental mode have the smallest loss in waveguide structures?

Why does the fundamental mode have the smallest loss in waveguide structures?And why the higher the order of the mode,the smaller the value of the angle between the light and the normal vector on the ...
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1answer
643 views

Why the relationship $v_p v_g = c^2$ (phase velocity multiply group velocity equals lightspeed squared) exists in waveguide structures?

What’s the reason that the relationship of de Broglie hypothesis(hypothesis-->relations) will hold in Waveguide structures?
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1answer
335 views

Why TE0 mode does not exist in parallel plates?

In parallel plates, TM0 mode will become TEM0 mode, but why TE0 mode does not exist? How to explain it with its physical properties?
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3answers
117 views

Propagating modes in a waveguide, what do they represent?

In a hollow rectangular wave guide of dimensions $a \times b$ for example, I know how to apply the boundary conditions to find the solutions. In particular, for TE (or TM) modes we have the expression ...
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1answer
98 views

Why can't $m$ or $n$ be zero on $TMmn$ mode in a rectangular waveguide?

The question is that is there any analytical or practical issue if m or n become zero in TMmn mode for a rectangular waveguide? It could probably be a simple question but I'm not sure about why does ...
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2answers
422 views

Standing wave ratio inside a waveguide

If there were microwaves being transmitted through the waveguide in the image below out the horn, and I place a sheet of metal in front of the horn (perpendicular to the propagation of the waves), ...
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1answer
57 views

Input impedances of terminated sections of transmission line

When dealing with optics and dielectric waveguides, a way to obtain the guided modes is to impose the "transverse resonance condition". Let the following be a transmission line with characteristic ...
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1answer
675 views

The boundary conditions in a waveguide

Suppose a cubic waveguide, made of perfect conductor, has only two open parallel sides. And the boundary conditions in this case are that the electric field at the surface must satisfy: $$\vec{B} \...
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1answer
86 views

Boundary condition on $\mathbf{B}$ to describe resonant cavities from waveguides

In Jackson- Classical Electrodynamics when resonant cavities are discussed (8.6, page 252) (but also at page 7 here or at page 19 here) the explanation is made by saying that the solution is the same ...
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1answer
946 views

Imaginary components of Poynting vector in rectangular waveguide

Consider a rectangular wave guide, as in the example of Jackson - Classical Electrodynamics The Poynting vector turns out to be $$\vec{S}=\epsilon c^2 \vec{E_0} \times \vec{B_0} e^{2i(kct-\alpha z)}...
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1answer
67 views

Need help understanding another answer on TEM coaxial cable modes

Background: If I make a coaxial waveguide from the gap between two long, perfectly conducting, coaxial cylindrical surfaces, (e.g. perfect "coax" cable), then if I apply charges of $+q$ and $-q$ to ...
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63 views

Propagation of multiple photons in a waveguide lattice

Hamiltonian describing photonic lattice made of N elements can be written as: $$H = \hbar\sum_{i=1}^{N} (\beta_{i} \hat{a}_{i}^{\dagger}\hat{a}_{i}+\sum_{j=1}^{N}\kappa _{ij} \hat{a}_{j}^{\dagger}\...
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97 views

Waveguide eigenmode weak-form (Comsol)

Maxwell equations are: $$\nabla \times \mathbf{E} = -\frac{\partial \mathbf{B}}{\partial t},\,\,\,\,\,\,\,\,\nabla \times \mathbf{H} = +\frac{\partial \mathbf{D}}{\partial t}$$ Subject to the ...
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1answer
733 views

Meaning of imaginary part of complex field amplitude for waveguide modes (e.g. TE, TM, HE, EH)

In classical waveguide analysis (e.g. for optical fibers, as in the notes Modal analysis of step-index fibers, ECE 4006/5166 Guided Wave Optics, Robert R. McLeod, University of Colorado), one can find ...
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2answers
199 views

Waveguide horn antenna & inverse square law

With a lab waveguide / horn antenna setup similar to image (without bends), we made the following measurements. Now we thought this could be used to demonstrate the observation of the inverse square ...
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3answers
276 views

Does light travel through a waveguide faster than electricity through a wire

So I have heard that using photons to compute is faster than electrons. I was wondering why exactly that is? Is it because light travels through a waveguide faster than electricity through a wire?
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118 views

Electromagnetic Wave In Toroidal and Helical Waveguide

Is there an analytic solution for the propagation (modes) of electromagnetic wave in a toroidal and helical waveguide? References would be appreciated too.
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1answer
117 views

Electromagnetic wave pattern in waveguide for differnt modes like TE10,TM11

I have read about different waveguide and their different modes like TE10,TE11..etc. in many books, EM wave pattern was given. they are saying that they have drawn from waveguide's equations. but i ...
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429 views

What is the cutoff frequency of a dielectric rectangular waveguide?

I'm wondering if anyone know what is the cutoff frequency of a dielectric rectangular waveguide. The most papers and books I can find talking about the cutoff frequency of a rectangular waveguides are ...
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1answer
123 views

What is a quarter wave flange in waveguide?

I have been searching about a quarter-wave flange online. But I could not find a single website about the principle of its operation. Can someone give me an idea of its operation or where I can find ...