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PN optical modulator

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Hello,

I am a student in TUD and I have started to work with COMSOL. My task is to model and simulate PN silicon optical modulator.
I am using Semiconductor module. I have couple of questions I would highly appreciate if you help me with that.

My structure consists of p+, p, n and n+ regions I am using metal contacts on p+ and n+ regions and applying voltage. I have also added "Trap assisted recombination" and "Auger recombination" physics. Do I need some more physics ?


1) I am a bit confused with the doping profiles in COMSOL. Currently I am using Analytic doping profile and using "user defined" distribution for all the parts in my structure. Is this correct approach ?

2) I need also to calculate the resistance and capacitance of my structure. Is it possible with comsol ? if yes how can I do that ?

3) I need to extract carrier distribution in txt file. So I am doing it from 2D figure and I have x y and value(color). But I would like to control x and y. I mean to say I want for example 1000 x and 500 y. Is it possible ?

Thank you in advance.
Best regards,
Levon

2 Replies Last Post Aug 16, 2017, 12:46 a.m. EDT
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Hello Levon Mirzoyan

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Posted: 7 years ago Jun 5, 2017, 3:17 a.m. EDT
Hello Levon,

It seems that you are working on the optical modulator using COMSOL for quite a long time and has gained sufficient experience on it...

I am a project fellow in University of Calcutta, India and trying my hands on simulating the modulator part using COMSOL... It will be very kind of you if I get some guidelines from you regarding this as I am completely novice in this field.

I am trying a simple p-i-n structure for the modulator. Is it possible to achieve the optical characterization (say for example modulation depth, bandwidth factor, reflectivity-transmissivity dependence on the applied voltage, insertion loss and so on) of the modulator using COMSOL?

It seems that I will have to use the semiconductor module for developing the structure. So is it possible to optically excite the structure using that module and then how to proceed (i.e. which category of 'physics', 'study' and so on will be suitable) for simulating the optical features?

If not then what is the correct procedure?

Hoping to get a quick response from you as I am experiencing a complete clueless ambience around me,
I Thank you in advance.
Best regards,
Srinjoy
Hello Levon, It seems that you are working on the optical modulator using COMSOL for quite a long time and has gained sufficient experience on it... I am a project fellow in University of Calcutta, India and trying my hands on simulating the modulator part using COMSOL... It will be very kind of you if I get some guidelines from you regarding this as I am completely novice in this field. I am trying a simple p-i-n structure for the modulator. Is it possible to achieve the optical characterization (say for example modulation depth, bandwidth factor, reflectivity-transmissivity dependence on the applied voltage, insertion loss and so on) of the modulator using COMSOL? It seems that I will have to use the semiconductor module for developing the structure. So is it possible to optically excite the structure using that module and then how to proceed (i.e. which category of 'physics', 'study' and so on will be suitable) for simulating the optical features? If not then what is the correct procedure? Hoping to get a quick response from you as I am experiencing a complete clueless ambience around me, I Thank you in advance. Best regards, Srinjoy

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Posted: 7 years ago Aug 16, 2017, 12:46 a.m. EDT
Dear Levon!

It is interesting that you are trying to model PN junction based optical modulator. I have following comments on this:
1. Besides semiconductor module, I think wave-optic module in COMSOL is also required for characterizing PN junction.
2. PN junction can work as a phase shifter based on a plasma dispersion effect i.e. change in refractive index with respect to change in carrier concentration. And carrier concentrations are varied based on applied voltage.
3. Dimensions of PN junction should be optimized for the single mode light propagation for which wave-optics module is essential.

With best wishes,
(Subhash Arya)
NEHU, Shillong
Dear Levon! It is interesting that you are trying to model PN junction based optical modulator. I have following comments on this: 1. Besides semiconductor module, I think wave-optic module in COMSOL is also required for characterizing PN junction. 2. PN junction can work as a phase shifter based on a plasma dispersion effect i.e. change in refractive index with respect to change in carrier concentration. And carrier concentrations are varied based on applied voltage. 3. Dimensions of PN junction should be optimized for the single mode light propagation for which wave-optics module is essential. With best wishes, (Subhash Arya) NEHU, Shillong

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