tapered waveguide

[Dr. MohammadMahdi Ariannejad]

How to design a tapered wave guide to increase the efficiency? in my case I have 9 micron fiber to wave guide is 2um so I have to design on taper that can change 9 micron to 2 micron the problem is high lost and still I am looking for single mode, please help me about it? any file of tutorial that I can refer?
Is the “Create a Chip-to-fiber Butt Coupler” suit for this matter? thanks.

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[Dr. MohammadMahdi Ariannejad]

the tapered is better to be with the main design or different? I mean first I should do the main design then do the tapered? many thanks

[Damian Marek]

I would say start with the main design (two waveguides to be coupled) first. Then attempt a taper design. You will probably have to go back and forth between them until you can find a good middle ground. The larger the differences are between the waveguides the harder it will be to make a good taper or connection between them.

Regards

[Dr. MohammadMahdi Ariannejad]

my fiber is 8 micron and my waveguide is 2 micron, still I am designing the single mode, I just reached to 5 micron to 2 micron is single mode, even for 6micron to 2 micron I got 2 mode, and I have to go for 8 to 2 micron, I totally confused any solution? many thanks.

[Dr. MohammadMahdi Ariannejad]

even for 8 micron planar wave guide I just get 3 modes no matter how long it is! is there any way to have a tapper that can exchange from 8 micron to the 2 micron?

[Dr. MohammadMahdi Ariannejad]

I seriously need to make tapper from 8 micron that I suppose to connect to the fiber to the 2 micron that I will connect to my wave guide. just in case just let me know any possibilities to design single mode within this matter? please inform me about it many thanks.

[Damian Marek]

What type of constraints do you have? Does the waveguide sit directly on the substrate? The material that makes up the ridge waveguide has a very high index of refraction in your project file 3.45 can you use a different material?

[Dr. MohammadMahdi Ariannejad]

it is straight connected I am using SOI, unfortunately no I cannot because I have to do the fabrication with it and it cannot be changed, is there any solution to wave this problem?

[Damian Marek]

I found a very well written and explained PHD thesis on this subject:

http://www.mit.edu/~winnieye/ThesisWY.pdf

The first section is probably what you need. Try simulating some of their designs to get a single mode waveguide.

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