June 29, 2015, 7:47 a.m.

Fiber Optic Transmission Lines

fiber, волс, модовая дисперсия

Distinguish mode dispersion, which is caused by a large number of modes in the optical fiber and the chromatic dispersion associated with the incoherence of light sources actually operating in a certain range of wavelengths.

Consider the propagation of the light beam along the multimode fiber. In this case there are two modes, the two beams. The first extends along the longitudinal axis of the fiber, while the other is reflected from the interfaces of media. Thus the path of the second light beam is greater than the first. As a result, when the two beams carrying the electromagnetic energy are added together, compared oblique beam with an axial beam is the time delay, which is calculated by the following formula:

c – speed of light
l – fiber length
n 1 , n 2 – refractive indices of the core and shell

June 29, 2015, 7:36 a.m.

Fiber Optic Transmission Lines

fiber, волс, потери

The most important parameters are the optical fiber loss and attenuation of the transmitted energy. These parameters define the range of the FOC and on its effectiveness. Attenuation in optical fibers due to manifestation of the following losses:

α c – own loss of fiber waveguides
α k – additional cable losses
α ik – absorption loss in the infrared region
α pr – the loss caused by the presence of impurities in the optical fibers

Proper loss fibers consist, in turn, an absorption loss of α p and scattering loss α r :

Attenuation due to the absorption due to the losses on the dielectric polarization depends strongly on the properties of the fiber material and is calculated by the following formula:

tgδ – dielectric loss tangent

The attenuation in the infrared region, situated in the wavelength range of more than 1.6 microns, calculated by the formula:

C and k – constant coefficients. For quartz glass C = 0,9; k = (0,7—0,9) мкм.

June 28, 2015, 1:22 p.m.

Fiber Optic Transmission Lines

fiber, волс, типы волс

Depending on the number of the operating frequency propagating waves (modes) of the fibers and is separated into one multimode. The number of modes is dependent on the ratio of the diameter of the fiber core and the wavelength for optical fibers having step-index is calculated as follows.

α – fiber core radius,
λ – wavelength,
Δ – relative refractive index difference.

Since n 1 and n 2 have very similar meanings, the nominal value ∆ for most optical fibers is within

June 28, 2015, 12:37 p.m.

Fiber Optic Transmission Lines

fiber, волс, апертурный угол

The optical fiber is a thin glass strand bilayer, each element (core and shell) has a different refractive index. The refractive index n of transparent material is the ratio of the velocity of light in vacuo (c - velocity of light) to the speed of light in this material (v), and defined by the following formula:

where ε and μ — respectively, relative dielectric and magnetic permeabilities.

Given that the relative magnetic permeability of the transparent material is usually constant and equal to one, the refractive index of the core for n 1 = √ε 1 , and for the shell n 2 = √ε 2 .

m
May 19, 2019, 1:49 a.m.
mahhaki

Qt - Test 001. Signals and slots

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S
May 17, 2019, 1:14 p.m.
SunBro

Qt - Test 001. Signals and slots

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May 17, 2019, 4:18 a.m.
banana

C++ - Тест 003. Условия и циклы

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Last comments
May 20, 2019, 7:20 p.m.
Евгений Легоцкой

Добрый день! Вы не думали разместить репозиторий проекта на GitHub?
P.
May 18, 2019, 2:03 p.m.
PELMYACH .

Спасибо большое! Вскоре буду разбираться!
May 18, 2019, 9:13 a.m.
Евгений Легоцкой

Добрый день! Отнимать значение общего счётчика можно в деструкторе класса кнопки QDynamicButton::~QDynamicButton(){ ResID--;} При этом я бы ещё переустанавливал значения вс...
P.
May 14, 2019, 10:33 p.m.
PELMYACH .

Здравствуйте!А не подскажите, как можно при удалении какой либо кнопки, у щётчика отнять значение?Дабы например четвёртой кнопке соответствовал ID 4, а не 5 скажем
May 6, 2019, 6:39 a.m.
Евгений Легоцкой

Добрый день. Этот урок для Qt Quick Control версии 1, Вы используете вторую версию. Здесь style уже нет, кастомизацию можно делать уже или черещ соответствующие property или через ...
Now discuss on the forum
I
May 21, 2019, 1:38 p.m.
Intruder

Всем доброго времени суток. Прошу помощи у сообщества, как начинающий программист. Есть задача реализовать динамическую библиотеку на Qt5.12.3. Поискав на просторах Интернета нашел немал...
May 20, 2019, 8:43 a.m.
Михаиллл

Кинул библиотеки в папку с проектом и в папку к компилируемым файлам.В файле проекта прописал так, но все равно выдает ту же ошибку QT += core gui networkgreaterThan(QT_MAJOR_VERSI...
May 20, 2019, 1:47 a.m.
linq

Что вы понимаете под статической сборкой приложений? В какой среде?
May 19, 2019, 10:52 a.m.
Евгений Легоцкой

Если честно, то мне нужно самому время потратить, чтобы глянуть это дело. Я использовал Flutter для разработки, а не Qt. Просто исходя из опыта, могу сказать, что по большей части всё на эмуля...
May 16, 2019, 11:08 p.m.
BlinCT

Решил через indexOf сделать. Возвращает или номер позиции где нашел символ или строку или -1 если не найдено.

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