FOTL - Tutorial 002.The optical fiber and its types

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

The advantage of single-mode optical fibers is the low dispersion (signal distortion), a large information-carrying capacity and range. Single-mode systems are the most actively developing and still promising direction of development of information transmission technology.

In multimode fibers pulse on the reception is broadened and distorted, which significantly limits the transmitted frequency band and the transmission distance. Multimode fibers are not used to transmit information over long distances. Generally transceivers operating on multimode fiber limited range of up to 500 meters.

For the characteristics of the optical fiber is essential in the refractive index profile in cross section. If the core of the fiber has a constant value over the radius of the refractive index, such optical fibers are called fiber optics with step refractive index profile (there is a step in the refractive index at the interface between the core and shell).

Also to fight with the broadening of pulses (that is especially true for multimode fibers) developed another type of fiber, which is found much more widely used in long-distance communications - is the optical fiber having a gradient refractive index profile. In optical fibers with a graded refractive index from the refractive index of the core center to the edge changes smoothly.

The refractive index is described by the following formula for the gradient optical fibers

r – the current range,
n 1 – the greatest value of the refractive index of the core,
g – coefficient determining the type of refractive index profile

Single-mode optical fibers can be divided into the following categories:

  • conventional or fiber unbiased variance (SF), which are issued for equipment operating at a wavelength of 1.31 microns;
  • dispersion-shifted fiber (DSF), which are available for use at a wavelength of 1.55 microns;
  • fibers with non-zero dispersion-shifted (NZDSF), for transmitting a multiplex signal in the working wave range of 1,53-1,56 mm

It is also distinguished from the aligned optical fiber cladding whose refractive index corresponds to the refractive index of optical fibers and with a stepped profile matched to the refractive index of pure quartz (n = 1,4585), and the depressed cladding material which consists of two zones.

The profiles of optical fibers with refractive indices unbiased variance:
а – aligned with the shell, б – a depressed shell

The single-mode optical fibers for dispersion-shifted complex refractive index profiles determining the core diameter is substantial difficulties, so these fibers introduce the concept of the mode field diameter. fashion subfield refers to the area of the light signal passing through the cross-section of the optical fiber. This field has a minimal optical signal attenuation and optical fiber extends along minimal power losses.

ω 0 – mode field radius
0 – mode field diameter

Virtual hosting with 10 percent discount
Virtual hosting with 10 percent discount
EVILEG offers reliable hosting with a 10% discount for virtual hosting and 5% for VPS
Support the author Donate


Only authorized users can post comments.
Please, Log in or Sign up
June 25, 2019, 2:41 p.m.

C++ - Test 001. The first program and data types

  • Result:40points,
  • Rating points-8
June 25, 2019, 9:16 a.m.

C ++ - Test 004. Pointers, Arrays and Loops

  • Result:40points,
  • Rating points-8
June 24, 2019, 5:49 p.m.
Serg Zhi

C++ - Тест 003. Условия и циклы

  • Result:78points,
  • Rating points2
Last comments
June 24, 2019, 10:23 a.m.
Евгений Легоцкой

Хорошо, ну будут проблемы помимо того, что касается статей, то не стесняйтесь задавать вопросы на форуме.
June 24, 2019, 10:21 a.m.
Михаил Булатов

Извиняюсь, все работает(из-за невнимательности).
June 24, 2019, 9:52 a.m.
Евгений Легоцкой

Придётся делать ещё сигнал в дочернем qml и пробрасывать через коннекты и обработчики. А вообще нужно смотреть конкретный код и что вы пытаетесь сделать. Так что лучше будет, если вы зад...
June 21, 2019, 8:31 a.m.
Ruslan Polupan

Вот моя строка по которой все отлично сработало %cqtdeployer% -bin c:/CentralMposKeys/CentalMposKeys.exe -qmake c:/Qt/5.12.2/mingw73_64/bin/qmake.exe
June 21, 2019, 8:24 a.m.
Андрей Янкович

Возможно кому то пригодится сqtdeployer для windows работает точно так же как и для Linux разница лишь в команде запуска Linux: cqtdeployer Windows: %cqtdeployer...
Now discuss on the forum
June 26, 2019, 6:10 p.m.
Евгений Легоцкой

Попробуйте включить все триггеры редактирования у TableView, а потом уже немного поиграться с ними, если заработает. tableView->setEditTriggers(QAbstractItemView::AllEditTriggers);
June 26, 2019, 4:22 p.m.

Похоже никак и нужно использовать вебвью
June 26, 2019, 4:13 p.m.

Таке попробовал сделать так, но не работает вы вырубается при загрузкею.Может быть вы знаете, как это можно исправить? //import QtWebEngine 1.9import QtWebView 1.13Item { width: 4...
June 26, 2019, 7:55 a.m.

Пробовал перезапускать qmake, удалять папку билд. Не помогало. Потом перезапустил сам Qt, и помогло. Жутко глючит. Сейчас опять сталкиваюсь с подобными багами.
June 26, 2019, 7:07 a.m.
Евгений Легоцкой

Да, работает. Но это решение подходит в основном для отоюражения статической информацию, которая не меняется. А TableView или ListView позволяют работать с моделями данных и редактировать их, ...
Looking for a Job?
10,000.00 руб. - 15,000.00 руб.
Нужен помощник для создания API.
Moscow, Moscow, Russia
25,000.00 руб. - 30,000.00 руб.
Разработчик Qt/C++
Barnaul, Altai Krai, Russia

For registered users on the site there is a minimum amount of advertising

Join us
© EVILEG 2015-2019
Recommend hosting TIMEWEB