## File: New > Other Waveguide

## The Other Waveguide Module

You use the Other Waveguide Module to model general waveguides with a grating.

In this module, the user needs to define the mode properties instead of the waveguide

profile in the other modules. The Other Waveguide module finds application in WDM

add/drop filters, Bragg gratings, Long Period Gratings.

## To choose the Other Waveguide module

1 | File > New. |

2 | New > Other Waveguide. |

## The Mode Properties Dialog Box

In this dialog box, you enter the main data concerning the mode properties of the

waveguide.

## To open the mode properties dialog box

1 | In the Project window, click the Mode Parameters button. |

2 | In the Mode Properties dialog box, you can define the following options: |

**Input Mode**

**Effective Index Real** – The real part of the modal index of the input mode

**Effective Index Imaginary** – The imaginary part of the modal index of the input mode

**Overlap Integral** – The overlap integral value of the input mode in the grating region.

The Overlap Integral in the Input Mode panel is the overlap integral of the input field

with itself. This quantity is also called Confinement Factor.

**Real** – Check this box when the effective index is pure real. Otherwise uncheck this box.

**Add**

If only the Input Mode panel contains data, then the simulation will be for a single

mode waveguide that has a single transmission and reflection spectrum. If the

waveguide has more than one mode, and the grating causes coupling among the

forward and backward directions in those other modes, the software will need more

data to define the parameters of the additional modes. This button allows you to add

the information about a new mode by adding an item at the end of the mode list.

**Insert**

This button allows you to insert a new line for mode information before the current

selected line.

**Edit**

This button allows you to edit the selected line.

**Delete**

This button is used to delete a selected line.

**Delete All**

This button deletes all the items in the mode list.

**Mode Name**

Name of the mode in the mode list.

**Eff. Ind. Real**

Real part of the modal index of the mode in the list

**Eff. Ind. Imaginary**

Imaginary part of the modal index of the mode in the list

**Overlap Integral**

In the mode list, the Overlap integral (OLI) is the overlap integral value between the

mode in the mode list and the input mode, where the integral is evaluated over the

grating region.

Ω is the region in the transverse (x,y) plane occupied by the grating. *E _{1}* and

*E*

_{2}are the mode field patterns of the input mode and the higher order mode and both are

normalized to unity i.e

Note that the Overlap Integral in the Input Mode panel is the overlap integral of the

input field with itself. This quantity is also called Confinement Factor.

## Using Calculation Options

The calculation options are similar to the ones described in Single Fiber calculation

section.