Can I model modulated optical source using the global shutter in DEVICE?


#1

Hi,

The shutter can be used to turn on/off optical generation objects in CHARGE solver when there’s an imported generation rate source in the structure. But for practical usage, I’ve been wondered that can the Source Shutter or something relevant in DEVICE can be used to simulate the carrier response (change in current/voltage) to the modulated laser light (sequence of modulated square wave forms) with different modulation frequency to give similar modulation response as below (cited from journal paper)

It would be extremely helpful if the bandwidth limitation to the modulated light can be studied by applying a sequence of small-signal square/sine waves and observe response current/voltage. Any suggestion?

Thank you for your support!


How to use the Global Source Shutter in DEVICE
#2

Hi. Unfortunately the shutter in the CHARGE solver only supports turning the light source on and off (including pulse on and off). It is not possible to apply a modulating signal on the source. However, it should be possible to simulate the current/voltage output for a modulated optical input by first extracting the RC parameters for your photodetector along with its responsivity using DEVICE and then by creating a compact model for the detector in Interconnect to simulate the output.

The compact model for the detector in Interconnect might be combination of an RC filter (to model the bandwidth of the detector) in series with a photodetector whose responsivity is set using the data from DEVICE simulation.


#3

Hi,
Thank you for your input. Would you suggest me some Lumerical examples related to (i) how to extract the RC parameters for photodetector in DEVICE and (ii) bandwidth measurement in Interconnect.

I look forward to do some similar simulation on modulation response with Lumerical solutions.


#4

Hi. Sorry about the late reply. You can check the Mach Zehnder Modulator example to see how DEVICE can be used to measure the capacitance of a pn junction. If you want to measure the resistance of the device, you can simply put a metal contact on top of the junction to measure the resistance of the p side and n side separately.

For the INTERCONNECT part, please take a look at this example Traveling Wave Modulators. You will see that the example calculates the output waveform from the photodetector for a certain input signal. The bandwidth of the photodetector is modeled using a low pass filter whose bandwidth you can determine from the RC values achieved from DEVICE simulations.


#5

Hi, wonderful. These may be exactly the functions I need. Let me start working on it.

Thank you for your help !