Nonlinear Waveguide (WGD) - INTERCONNECT Element – Ansys Optics

INTERCONNECT

Nonlinear waveguide

Keywords

optical, bidirectional

Ports

Name	Type
port 1	Optical Signal
port 2	Optical Signal

Properties

General Properties

Name	Default value	Default unit	Range
name Defines the name of the element.	Nonlinear Waveguide	-	-
annotate Defines whether or not to display annotations on the schematic editor.	true	-	[true, false]
enabled Defines whether or not the element is enabled.	true	-	[true, false]
type Defines the element unique type (read only).	Nonlinear Waveguide	-	-
description A brief description of the elements functionality.	Nonlinear waveguide	-	-
prefix Defines the element name prefix.	WGD	-	-
model Defines the element model name.	-	-	-
library Defines the element location or source in the library (custom or design kit).	-	-	-
local path Defines the local path or working folder $LOCAL for the element.	-	-	-
url An optional URL address pointing to the element online help.	-	-	-

Standard Properties

Name

Default value

Default unit

Range

configuration

Defines the bidirectional or unidirectional element configuration.

bidirectional

[bidirectional, unidirectional

frequency

Central frequency of operation.

193.1

THz*

*std. unit is Hz

(0, +∞)

length

The interaction length of the modulator.

[0, +∞)

Waveguide/Mode 1 Properties

Name

Default value

Default unit

Range

orthogonal identifier 1

The first identifier used to track an orthogonal mode of an optical waveguide. For most waveguide, two orthogonal identifiers '1' and '2' are available (with the default labels 'TE' and 'TM' respectively).

[1, +∞)

label 1

The label corresponding to the first orthogonal identifier.

confinement factor 1

Defines the mode confinement factor.

[0, 1]

Waveguide/Mode 2 Properties

Name

Default value

Default unit

Range

orthogonal identifier 2

The second identifier used to track an orthogonal mode of an optical waveguide. For most waveguide, two orthogonal identifiers '1' and '2' are available (with the default labels 'TE' and 'TM' respectively).

[1, +∞)

label 2

The label corresponding to the second orthogonal identifier.

confinement factor 2

Defines the mode confinement factor.

[0, 1]

Waveguide/Nonlinearities Properties

Name	Default value	Default unit	Range
free carrier induced nonlinearity Defines whether or not to enable free carrier induced nonlinearities.	true	-	[true, false]
free carrier time constant Free carrier induced nonlinearities time constant.	1e-009	s	[0, +∞)
load free carrier index perturbation from file Defines whether or not to load the free carrier index perturbation from an input file or to use the currently stored values.	false	-	[true, false]
free carrier index perturbation filename The file containing power dependent free carrier index perturbation values. Refer to the Implementation Details section for the format expected.	-	-	-
free carrier index perturbation table The table containing the free carrier index perturbation values	<7,3> [0, 0.0025, 0.005,...]	-	-
thermally induced nonlinearity Defines whether or not to enable thermally induced nonlinearities.	true	-	[true, false]
thermal time constant Thermally induced nonlinearities time constant.	100e-009	s	[0, +∞)
load thermal index perturbation from file Defines whether or not to load the thermal index perturbation from an input file or to use the currently stored values.	false	-	[true, false]
thermal index perturbation filename The file containing power dependent thermal index perturbation values. Refer to the Implementation Details section for the format expected.	-	-	-
thermal index perturbation table The table containing the thermal index perturbation values	<7,3> [0, 0.0025, 0.005,...]	-	-

Numerical Properties

Name

Default value

Default unit

Range

convert noise bins

Defines if noise bins are incorporated into the signal waveform.

true

[true, false]

automatic seed

Defines whether or not to automatically create an unique seed value for each instance of this element. The seed will be the same for each simulation run.

true

[true, false]

seed

The value of the seed for the random number generator. A value zero recreates an unique seed for each simulation run.

[0, +∞)

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Implementation Details

The Nonlinear Waveguide element models the nonlinearity properties based on free carrier and thermal effects in waveguide. This element need to be used in conjunction with normal waveguide elements such as Straight Waveguide. User can define time constant and index perturbation in regarding to free carrier and thermal effect in this model to define waveguide nonlinear effect. The index perturbation is power based and can be loaded from text files.

The Nonlinear Waveguide element functions similar to the Optical Modulator Measured element, except instead of an electrical signal the power of the optical signal input is used to determine the effective index used by the waveguide.

The value of the real and imaginary effective index of the Nonlinear Waveguide element is calculated by looking up the values that correspond to the input optical power scaled by the confinement factor of the mode in the free carrier index perturbation table and thermal index perturbation table. The values from these two tables are added together to get the total effective index.

If the free carrier time constant or thermal time constant are non-zero, the optical power used to calculate the effective index in the corresponding table is averaged over a duration equal to the time constant.

Following is an example showing the waveguide nonlinear effect with and without time constant.