modulates an optical signal depending on electrical signal
Keywords
electrical, optical, bidirectional
Ports
| Name | Type |
|---|---|
| port 1 | Optical Signal |
| modulation | Electrical Signal |
| port 2 | Optical Signal |
Properties
General Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
name Defines the name of the element. |
Optical Ring Modulator | - | - |
|
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). |
Optical Ring Modulator | - | - |
|
description A brief description of the elements functionality. |
modulates an optical signal depending on electrical signal | - | - |
|
prefix Defines the element name prefix. |
RING | - | - |
|
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 the waveguide. A Taylor expansion around this frequency is performed to estimate the propagation transfer function of the waveguide. |
193.1 |
THz* *std. unit is Hz |
(0, +∞) |
|
length The length of the waveguide. |
10e-006 | m | [0, +∞) |
|
load from file Defines whether or not to load measurements from an input file or to use the currently stored values. |
false | - | [true, false] |
|
measurement filename The file containing the measurement data. Refer to the Implementation Details section for the format expected. |
- | - | - |
|
measurement type Defines the type of measurement data. |
effective index | - | [absorption & phase, effective index |
|
measurement A matrix editor for users to read the element current modulation data values. |
<6,3> [0, 0.2, 0.4,...] | - | - |
Waveguide Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
loss Defines the waveguide loss. |
0 | dB/m | [0, +∞) |
|
effective index Defines the waveguide effective index. |
1 | - | (-∞, +∞) |
|
group index Defines the waveguide group index. |
1 | - | [0, +∞) |
|
dispersion Defines the waveguide dispersion. |
0 | s/m/m | (-∞, +∞) |
|
dispersion slope Defines the waveguide dispersion slope. |
0 | s/m^2/m | (-∞, +∞) |
|
coupling coefficient 1 The power coupling coefficient corresponding to the first coupler. |
0.5 | - | [0, 1] |
|
coupling coefficient 2 The power coupling coefficient corresponding to the second coupler. |
0.5 | - | [0, 1] |
|
modes List of optical mode labels supported by the element. |
TE,TM | - | - |
Thermal Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
thermal effects Defines whether or not to enable thermal effects. |
false | - | [true, false] |
|
temperature Defines the temperature. |
%temperature% | K | (-∞, +∞) |
|
nominal temperature Defines the nominal temperature where temperature sensitivity values are measured. |
300 | K | (-∞, +∞) |
|
thermal fill factor The waveguide length ratio affected by the thermal effects. |
1 | - | [0, 1] |
|
effective index temperature sensitivity Defines the ratio between effective index variation and temperature. |
0 | /m/k | (-∞, +∞) |
|
excess loss temperature sensitivity Defines the ratio between loss variation and temperature. |
0 | dB/m/K | [0, +∞) |
Enhanced Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
electrical fill factor The waveguide length ratio affected by the modulation. |
1 | - | [0, 1] |
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. |
1 | - | [0, +∞) |
Numerical/Digital Filter Properties
| Name | Default value | Default unit | Range |
|---|---|---|---|
|
time variant digital filter Defines the operation of the internal time varying digital filter. |
disable | - | [disable, interpolate, update |
|
single tap filter Defines whether or not to use a single tap digital filter to represent the element transfer function in time domain. |
false | - | [true, false] |
|
number of taps estimation Defines the method used to estimate the number of taps of the digital filter. |
fit tolerance | - | [disabled, fit tolerance, group delay |
|
filter fit tolerance Defines the mean square error for the fitting function. |
0.001 | - | (0, 1) |
|
window function Defines the window type for the digital filter. |
rectangular | - | [rectangular, hamming, hanning |
|
number of fir taps Defines the number of coefficients for digital filter. |
256 | - | [1, +∞) |
|
maximum number of fir taps Defines the number of coefficients for digital filter. |
4096 | - | [1, +∞) |
|
filter delay Defines the time delay equivalent to a number of coefficients for digital filter. |
0 | s | [0, +∞) |
|
initialize filter taps Defines whether to use the initial input signal to initialize filter state values or to set them to zero values. |
false | - | [true, false] |
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
An optical ring modulator is usually used in wavelength division multiplexing (WDM) systems to isolate a wavelength out of the multiplexed signal. The INTERCONNECT ring modulator model contains a time-varying frequency transfer function that represents the relationship between the input and through port. This quasi-static behavior allows for using the ring modulator not only as a modulator but also as a filter or multiplexer device when cascading multiple ring modulators. In this example, we characterize the time domain and frequency domain performances of the ring modulator, please see the example file Optical_Ring_Modulator.icp. The following figure is the setting of the optical ring modulator.
The required input file measurement type could be selected from "effective index" and "absorption & phase". Please see the example measurement input file neff_vs_voltage_11.txt which goes under the "effective index" type.
Please note that, the two optical ports for the carrier light path are the "in" and "through" ports of the double bus ring. |
Frequency Domain Characterization
The frequency domain characterization of the optical ring modulator gives the following transmission response, it isolates out the signal with a wavelength around 1309.8nm.
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Fig. 1 Frequency domain transmission response of the optical ring modulator |
Time Domain Characterization
There are three numerical methods to calculate for the time variant digital filter coefficients. User can choose among "disable", "interpolate" and "update" for the filter type, please see the whitepaper on INTERCONNECT Ring Modulator Model for the detailed explanation of the simulation methodology. For the system shown above, the following figure shows the output electrical signal for the three types of the time variant digital filter, respectively.
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The time domain characterization of the optical ring modulator gives the following results when the time variant filter is set to the "update" type. The blocked wavelength (1310nm) is much shorter than the transmission light wavelength (1552nm), hence there is no signal blocked.
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Fig.1 Received optical signal waveform (OOCS_1 output) |
Fig. 2 Received optical signal spectrum (OSA_1 output) |
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Fig. 3 Transmitted electrical signal (OSC_2 output) |
Fig. 4 Received electrical signal (OSC_1 output) |