## What is OptiFiber?

Telecommunications using fibers as the transmission media is now a major industry.

Choosing appropriate fiber parameters is an important issue for a given optical

system. Cross-sectional dimensions, material composition, and refractive index

profile all influence the losses, dispersion and the nonlinearities of the fiber and must

be chosen carefully to achieve a satisfactory trade off for a given application.

All these parameters of existing fiber samples could be experimentally measured and

then the fiber manufacturing process adjusted towards an optimized production.

However, this trial and error approach is extremely slow, expensive and unreliable.

Moreover, some important fiber parameters, for example the total group-velocity

dispersion and the effective nonlinear coefficient, are not directly measurable with

compact tabletop devices. Because of that, the number of professionals who use an

appropriate fiber design and modeling software is growing constantly across the

photonics industry.

OptiFiber is the leading commercial product in that category. It is a powerful tool that

blends numerical mode solvers for fiber modes with calculation models for group

delay, group-velocity dispersion, effective mode area, losses, polarization mode

dispersion, effective nonlinearity, etc. Among the most powerful features of OptiFiber

are its abilities to predict how any given fiber could be optimized versus a design goal,

for example small, but non-zero dispersion and maximal mode area. In addition,

OptiFiber can supplement and extend the fiber characterization capabilities of real

laboratory devices, such as EXFO’s NR-9200 Optical Fiber Analyzer, by importing

and analyzing the refractive index profiles of real fiber samples. OptiFiber is an

indispensable tool for engineers, scientists and students who design fibers, fiber

components and optical communications systems.

## With OptiFiber the user can:

- Design a multilayer fiber with an arbitrary 2D refractive index profile by either:
- Defining the profile internally, using a library of built-in functions or a using a

user-specified formula - Importing an external profile (directly supports profiles scanned with NR-

9200) - Assign material dispersion based on Sellmeier model or user-defined functions
- Model material losses based on known experimental formulas
- Calculate the following characteristics of any supported mode, fundamental or

higher order: - Mode field pattern, displayed in a number of ways
- Effective refractive index and the propagation constant
- Group delay
- Three types of group-velocity dispersion (material, waveguide, total)
- Mode field diameters according to various definitions and eff. mode area
- Estimations of the cutoff wavelengths
- Macrobending, microbending and splicing losses
- Optimize the dependence of these characteristics on numerous technological

parameters of the fiber: - geometry, profile shape, composition.
- Calculate and visually compare the parameters of an arbitrary group of modes vs.

the mode number - Calculate birefringence effects induced by intrinsic or extrinsic perturbations
- Estimate the PMD based on stochastic model
- Use two alternative ways of defining the profile of the fiber:
- As a refractive index profile.
- As a dopant concentration profile.
- Access the models:
- Macrobending losses of higher order modes.
- Estimations of the cutoff wavelength as given by the ITU-T recommended

experimental - procedure.
- Effective mode area.
- Effective nonlinear refractive indices of arbitrary mode as determined by the

nonlinear indices of - the bulk materials and on the waveguiding properties of the fiber: shape of

mode pattern, degree of - confinement, etc.
- Access a rich material library
- Try the examples.
- Use experimental profiles of real fiber samples scanned with NR-9200 from

EXFO Inc.

## What is new in OptiFiber version 2.0

**Meshless mode solvers for LP and vector modes**. As with the original mode solver

of OptiFiber, the fibers can consist of an arbitrary number of concentric layers of

lossless materials, and graded index fibers can be approximated using a sequence of

constant index layers. The new mode solvers are different from the original one in that

they do not use meshes to approximate the structure. Instead, they find an exact

solution based on matching boundary conditions at layer boundaries. These mode

solvers should be especially useful for multimode fiber calculations, where there are

many modes in the spectrum. Another advantage of the meshless mode solver is the

calculation of fields far from the fiber. Meshing introduces finite difference errors of a

certain level, and fields weaker than the differencing error cannot be calculated. The meshless mode solvers, on the other hand, have the correct asymptotic behavior far

from the fiber, and can calculate fields of magnitude 10^{-15} or less. In OptiFiber

version 2.0, the desired mode solver is selected by radio button in the Modes dialog

box.

**Propagation over distance feature**. OptiFiber allows users to decompose an

arbitrary field into the modes of a multimode fiber. It calculates the complex

coefficients of the modes for the arbitrary field. Similarly, given the amplitude of a set

of modes, OptiFiber can display the sum (composition of modes). OptiFiber 2.0 can

also calculate this multimode field after propagating down the fiber by a specified

distance. The user enters a distance. Each of the complex coefficients of the modes

is multiplied by the appropriate phase factor, and the new field pattern is displayed in

the preview box.

## What is new in OptiFiber 2.1

In OptiFiber 2.1, four enhancements were introduced to the user interface. The first

two enhancements, radius specified instead of layer widths, and layer index specified

relative to cladding, are implemented in a Settings dialog box to customize data entry

and display according to user preference. The parabolic function layer was enhanced

with an option to reverse the sense of direction, and it is now possible to export the

data found in the Cutoff dialog box.

**Radius specified instead of layer widths**. In OptiFiber, the fiber profile is specified

as a list of Regions (layers) of various widths. There is a read only field to show the

position (radius) of the selected layer. It is now possible to enter the radius of the layer

instead of the layer width. In this option, the width field will become read only instead

of the position field.

**Layer index specified relative to cladding**. In the Fiber Profile dialog box, the

refractive index of the selected layer is displayed in the Refractive Index field. It is

now possible to specify the refractive index relative to the cladding layer instead. With

this option, when the last layer is selected, the cladding refractive index will be

displayed in the Refractive Index field. However, when other layers are selected, the

index of current layer relative to the cladding layer will be shown. Data entry is also

relative.

**Export Cutoff data**. An option to export this data to a text file has been added.

**Parabolic function layer can go both ways**. The parabolic layer has its extreme

value on the left side of the layer by default. Now the layer can have the extreme

value on the right side as well.