Optical waveguide branch
Keywords
optical, bidirectional
Ports
| Name | Type |
|---|---|
| port 1 | Optical Signal |
| port 2 | Optical Signal |
| port 3 | Optical Signal |
Properties
General Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
name Defines the name of the element. |
Waveguide Y Branch | - | - |
|
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). |
Waveguide Y Branch | - | - |
|
description A brief description of the elements functionality. |
Optical waveguide branch | - | - |
|
prefix Defines the element name prefix. |
Y | - | - |
|
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, splitter, combiner |
|
insertion loss Defines the insertion loss (attenuation). |
0 | dB | [0, +∞) |
|
input parameter Defines whether to provide the power coupling coefficient, measurements, or the cross over length. |
coupling coefficient | - | [coupling coefficient, length |
|
length The length of the waveguide. |
0 | m | [0, +∞) |
Waveguide Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
phase shift Lower arm additional phase shift. |
0 | rad | (-∞, +∞) |
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 | - | [1, +∞) |
|
label 1 The label corresponding to the first orthogonal identifier. |
TE | - | - |
|
coupling coefficient 1 The power coupling coefficient corresponding to the first orthogonal identifier. |
0.5 | - | [0, 1] |
|
cross over length 1 The cross over coupling length corresponding to the first orthogonal identifier. |
0 | m | [0, +∞) |
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). |
2 | - | [1, +∞) |
|
label 2 The label corresponding to the second orthogonal identifier. |
TM | - | - |
|
coupling coefficient 2 The power coupling coefficient corresponding to the second orthogonal identifier. |
0.5 | - | [0, 1] |
|
cross over length 2 The cross over coupling length corresponding to the second orthogonal identifier. |
0 | m | [0, +∞) |
Diagnostic Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
run diagnostic Enables the frequency response of the designed filter implementation and the ideal frequency response to be generated as results. |
false | - | [true, false] |
|
diagnostic size The number of frequency points used when calculating the filter frequency response. |
1024 | - | [2, +∞) |
Results
| Name | Description |
|---|---|
| diagnostic/response #/transmission | The complex transmission vs. frequency corresponding to the ideal and designed filter. |
| diagnostic/response #/gain | The gain vs. frequency corresponding to the ideal and designed filter. |
| diagnostic/response #/error | Mean square error comparing the frequency response of the designed filter implementation with the ideal frequency response. |
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Implementation Details
The Waveguide Y Branch (Y) element can be used to combine or split optical signals. The “configuration” property determines if the Y element splits signals (“splitter”), combines signals (“combiner”), or acts as a combined splitter/coupler (“bidirectional”).
These configurations are described below:
- Combiner: Two inputs and a single output. The signals from the inputs are combined and sent to the output. The amount of power from each input sent to the output is determined by the “coupling coefficient” (see below).
- Splitter: Single input and two outputs. The signal from the input is duplicated and sent to each of the outputs. The amount of power sent to each output is determined by the “coupling coefficient” (see below).
- Bidirectional: Multiple bidirectional ports. The ports are grouped on the opposite sides of the element, with “port 1” on one side and “port 2” and “port 3” on the other. The Y element acts as a splitter for signals input into port 1, with port 2 and port 3 as the outputs. The Y element acts as a combiner for signals input to port 2 and port 3, with port 1 as the output. The amount of power from each input sent to each output is determined by the “coupling coefficient” (see below).
On this page the properties of the bidirectional configuration will be described, as the combiner and splitter configurations are just unidirectional versions of the bidirectional configuration.
The transmission spectra between the ports are symmetric, so the transmission from port 1 to port 3 is the same as the transmission from port 3 to port 1, etc. The user specifies the power transmission coefficient T between port 1/port 3, and the transmission between port 1/port 2 is then 1 - T. An additional insertion loss can be specified as well, which is applied to all input signals. There is no transmission between port 2 and port 3, and there is no reflection, so for example, signals input into port 1 do not output into port 1. Multiple modes with are supported. The modes can have different coupling coefficients.
There are two methods to specify the power transmission coefficient T: the “coupling coefficient” and the “cross over length”. The method used is determined by the “input parameter” property. If the “cross over length” method is used, T is determined based on the ratio between the “length” property, with the “cross over length” specifying where T is maximum using the relation \(T = \sin(L/L_c)\), where L is the length and Lc is the cross over length. A phase shift can be applied to the transmission between port 1/port 3 with the “phase shift” property, but no phase can be applied to the transmission between port 1/port 2.
There is no frequency dependence for the transmission between the ports. However, due to the phase shift applied to the transmission between port 1/port 3, interference can occur between the inputs from port 2 and port 3.
In the INTERCONNECT Element library, the “Waveguide Splitter” element is the Y element in the “splitter” configuration, the “Waveguide Combiner” element is the Y element in the “combiner” configuration, and the “Waveguide Y Branch” element is the Y element in the “bidirectional” configuration. The configuration of these elements can be changed after adding them to the simulation.
Similar Elements
- Optical Splitter/Coupler: The “Optical Splitter/Coupler” element can also be used to split or combine optical signals. However, when splitting signals, the input signals are evenly split to all output ports, and when combining signals, each input contributes equally to the output. There can also be an arbitrary number of inputs (outputs) when combining (splitting) signals.