__Answer:__

Calculating terms like Bandwidth-Distance are handled within our product **OptiSystem**.

The division of **OptiFiber** and **OptiSystem** is such:

**OptiFiber** is a component-level device software. It calculates some basic optical properties of a fiber. For example, given the radial refractive index profile and specified materials, it can calculate modes at various wavelengths. It can also calculate group delays and from that deduce modal dispersion. This data can be used by **OptiSystem**.

**OptiSystem** is a system level simulator which can work independently or in concert with **OptiFiber**. You would use this, for example, if you wanted to see how your fiber performed in a communications system. And indeed, Bandwidth-Distance is one of the parameters we calculate. **OptiSystem** has multi-mode fiber components. I suspect the components most helpful in this case would be our **Parabolic-Index Multimode Fiber** and our **Measured-Index Multimode Fiber**. There are a few ways that the refractive index profile can be defined:

1. Parabolic profile (in **Parabolic-Index Multimode Fiber**)

2. Alpha profile (in **Measured-Index Multimode Fiber**)

3. External file (in **Measured-Index Multimode Fiber**) – either a basic data file which specifies various values of index and at what radii they occur, or from an **OptiFiber** generated file.

Once all the parameters have been defined, **OptiSystem** will calculate the LP(m,n) modes. In our documentation, it states that the limit is LP(1000,1000), but we can extend that if necessary. The only real limits are computer memory and power.

I have attached the documentation for our **Measured-Index Multimode Fiber** component. At the bottom of page 8 is the result you are interested in, here just called Bandwidth.

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