[Amin KhorshidahmadParticipant]

Dear Nurettin,

There is a single design tab where you set the grating parameters in OptiGrating. It is just the grating period relative to the effective wavelength that determined the operation mode of the device.

Please make sure the “Auto” checkbox on the bottom-left corner of the “grating definition” tab is unchecked so that the “period” field becomes editable. Otherwise it would be automatically set based on the Bragg condition for the selected input modes.

Kind regards,
Amin

[Amin KhorshidahmadParticipant]

Hello Aulia,

Thanks for your inquiry;
In OptiGrating you may design your grating and calculate the transmission/reflection spectra under certain temperature and/or strain profile(s) in separate simulations. You may then export the spectra and load it into the “OptiGrating” component within OptiSystem. This component models the grating as a fixed filter. In your OSA setup please make sure the wavelength range is correctly centered around the source center frequency. You may shift the grating filter center frequency by checking the “user defined frequency” and then setting the “Frequency” within the OptiGrating component if required.
Please note OptiSystem also includes Fiber Bragg Grating and FBG Sensor components. The latter could be used to perform temperature and strain sweep simulation. Several FBG sensor examples can be found in the examples library of the OptiSystem under Sensor systems\FBG Sensor.

Please feel free to contact me at amin.khorshidahmad@optiwave.com for more info.

Kind regards,
Amin

[Amin KhorshidahmadParticipant]

Dear Saumendra,

Thanks for your inquiry;

In a waveguide coupler project, you may define the two waveguides, WG1 and WG2 (see the figure on page 144 of the OptiGrating Manual) each as a multi-layer slab structure. Please make sure the last region of WG1 and the first region of WG2 have exactly the same constant refractive index and the number of steps set to 1 for both; This forms the common layer for joining the two waveguides. The “distance” parameter in the “Waveguide Coupler Profile” tab sets the width of this common layer i.e., the distance between the waveguides. Note: the widths defined for the last region of WG1 and the first region of WG2 are both redundant.

Kind regards,
Amin

[Amin KhorshidahmadParticipant]

Hello Mahmoud,

If you could, please send us your OptiGrating design file to support@optiwave.com and I will look through…

Kind regards,
Amin

[Amin KhorshidahmadParticipant]

Hi Yaseen,

Please refer to page 22 of the manual for more details. In brief, Ind. Mod. (or delta_n) is the index modulation amplitude or the strength of the grating, e.g. peak refractive index change of the sinusoidal grating. Along with the length, It affects the bandwidth and reflectivity of the grating.

Kid regards,
Amin

[Amin KhorshidahmadParticipant]

Dear Ramya,

Thank you for sharing the designs with us.

I was wondering if you have access to an active license of OptiGrating (or any of our other products) or interested in acquiring such a modeling tool?

As I already mentioned, we are open to collaborate with academia and interested in having experimental verification for our simulation tools. In this regards, we are able to simulate your tilted FBG sensor designs and share the results to be verified against your experiments.

Kind regards,
Amin

[Amin KhorshidahmadParticipant]

Hi Ramya,

The OptiGrating currently does not support titled FBGs. However, we are in the process of releasing a component for tilted FBGs.
We would be happy to discuss your specific requirements and might be able to offer design-simulation services in the meantime. We are also open to partnership in research projects with academia.

BTW, please let me know if you had further issues using the trail version.

Kind regards,
Amin

[Amin KhorshidahmadParticipant]

Dear Ramya,

Thank you for your interest in OptiGrating. The trial version is fully functional for 30 days.
I would suggest copying the samples to another directory and verifying that you have indeed permission to modify and save design files. By default, they are installed in root directory and often users might have restricted access to C drive on office/university computers.
If the issue persists, please provide your windows version and we will try to emulate the setup environment.

Kind regards,
Amin

[Amin KhorshidahmadParticipant]

Hi Ricardo,

You can import the fiber profile from a file, e.g. listing radii-indices of each region. For custom grating profiles, however, the ‘user defined function’ option provides ultimate flexibility in defining the profile. You can simply define the shape function and possibly use the built-in scripting capability (similar to Basic, e.g. IF THEN ELSE etc.) to define desired shape function over the grating period. The function editing area comes with quick access (click & place from combo boxes) to global variables (x:the position variable varying from 0 to grating period, Period:grating period etc.), math functions and constants. You can readily run/debug the function and visualize the grating profile graphically with designing your profile. For complete list of capabilities and scripting commands please see Appendix A of the Manual.
You should be able to define a square profile with custom duty cycle through a conditional block using global ‘x’ and ‘Period’ variables.

Kind regards,
Amin

[Amin KhorshidahmadParticipant]

Hello Mahalakshmi,

In OptiFiber you design your fiber by specify the refractive index and width of each region. Regions are concentric layers staring from the center or fiber core at r=0.
You can specify the refractive index or the doping concentration of the regions by selecting the refractive index profile or dopant concentration distribution option respectively.
You can verify and check the RI profile in the “profile” tab and can readily measure/trace the RI profile graph.

Kind regards,
Amin

[Amin KhorshidahmadParticipant]

Hi,
Index modulation affects both the bandwidth and amplitude response of the grating. You may have a look at “Coupled-mode theory for guided-wave optics” by Yariv or coupled mode theory in any text book, e.g. Photonics by Yariv & Yeh, for details and quantitative analysis.

Kind regards,
Amin

[Amin KhorshidahmadParticipant]

Hi,

You may have a look at:
1- “Thermal dependence of the strain response of optical fibre Bragg gratings”, https://doi.org/10.1088/0957-0233/15/8/031
2- E. Filho, M. Baiad, M. Gagné, and R. Kashyap, “Fiber Bragg gratings for low-temperature measurement,” Opt. Express 22, 27681-27694 (2014).
3- A. Donko, M. Nuñez-Velazquez, P. Barua, F. Cruz, R. Ismaeel, T. Lee, J. Sahu, M. Beresna, and G. Brambilla, “Femtosecond inscription and thermal testing of Bragg gratings in high concentration (40 mol%) germania-doped optical fibre,” Opt. Express 25, 32879-32886 (2017).
4- General Reference: Handbook of Optical Constants of Solids by Palik

Kind Regards,
Amin