The CW laser model generates a continuous wave (CW) optical signal
Keywords
optical, unidirectional
Ports
| Name | Type |
|---|---|
| output | Optical Signal |
Properties
General Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
name Defines the name of the element. |
CW Laser | - | - |
|
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). |
CW Laser | - | - |
|
description A brief description of the elements functionality. |
The CW laser model generates a continuous wave (CW) optical signal | - | - |
|
prefix Defines the element name prefix. |
CWL | - | - |
|
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 |
|---|---|---|---|
|
frequency Central frequency of operation. |
193.1 |
THz* *std. unit is Hz |
(0, +∞) |
|
power The average output power. |
0 |
dBm* *std. unit is W |
(-∞, +∞) |
|
linewidth The output signal rms linewidth, full width at half max. |
0 |
MHz* *std. unit is Hz |
[0, +∞) |
|
linewidth distribution The rms linewdith distribution |
legacy | - | [legacy, Gaussian, Lorentzian |
|
phase The initial output signal phase. |
0 | rad | (-∞, +∞) |
Polarization Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
azimuth The azimuth angle (polarization ellipse) of the signal output. |
0 | rad | [-1.5708, 1.5708] |
|
ellipticity The ellipticity angle (polarization ellipse) of the signal output. |
0 | rad | [-0.785398, 0.785398] |
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. |
X | - | - |
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. |
Y | - | - |
Enhanced Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
enable RIN Defines whether or not to add RIN to the signal output. |
false | - | [true, false] |
|
RIN Defines the RIN at the reference power. |
-140 | dB/Hz | (-∞, +∞) |
|
reference power Reference power at which RIN was calculated. |
0 |
dBm* *std. unit is W |
(-∞, +∞) |
Numerical Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
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. |
1 | - | [0, +∞) |
Simulation Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
output signal mode The output signal mode. |
%output signal mode% | - | [sample, block |
|
number of output signals The number of simulation runs, or the number of generated signals. |
%number of output signals% | - | [1, +∞) |
|
sample rate The sample rate of the generated signal. This is typically set by the global properties in the root (top-most) element. |
%sample rate% | Hz | [0, +∞) |
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Implementation Details
The CW Laser element is used to generate an optical signal with a constant amplitude at a single wavelength/frequency for use in transient sample or block mode simulations. Along with the "frequency", "power" and initial output "phase" of the signal, the following properties can be set:
- Linewidth: The laser's "linewidth", defined using the full width at half maximum, can be set using either the "legacy", "Gaussian", or "Lorentzian" distributions. The "legacy" distribution should only be used for older files that were created before the implementation of the "Lorentzian" distribution. For all other files, the "Lorentzian" or "Gaussian" distributions should be used.
- Relative Intensity Noise (RIN): RIN can be added to the signal by setting "enable RIN" to "true", setting an RIN level with the "RIN" property, and defining a "reference power" (independent from the actual signal power).
- Polarization: The polarization of the signal can be defined using the "azimuth" and "ellipticity" angles, as defined below. Note that the polarization basis states are Mode 1 and Mode 2, which typically refer to the TE and TM modes, respectively.
State of Polarization
The state of polarization (SOP) of the CW Laser model is defined by using the polarization ellipse as shown in the figure below, where ω is the "ellipticity" angle and α is the "azimuth" angle, a and b are the major and minor axis of the ellipse, respectively. Then the unified Stokes Parameters are defined by the equation in the figure below.
$$
\left|\begin{array}{c}
S_{0} \\
S_{1} \\
S_{2} \\
S_{3}
\end{array}\right|=\left|\begin{array}{c}
1 \\
\cos (2 \omega) \cos (2 \alpha) \\
\cos (2 \omega) \sin (2 \alpha) \\
\sin (2 \omega)
\end{array}\right|
$$
Similar Elements
- Multimode CW Laser (MMCW): The MMCW element is similar to the CW Laser, but it can create optical signals in multiple orthogonal modes.
- Directly Modulated Laser (DML): The DML element can be used to model a laser that is directly modulated by an electrical signal. A simple laser model is used to determine the output signal based on the electrical signal input.
- Traveling Wave Laser Model (TWLM): The TWLM element implements a more complex laser model compared to the DML element.
Examples
The CW Laser element is used in the following examples: