Learning Forum

[jannatul nayem]

I want to create a spr biosensor where a portion of claading of fiber is removed and layer of gold ,graphene and analyte is added on that portion.a collimated source will pass through the fiber core.how would i design it and what kind of source i may use?the reflection coefficent of p plarized incident light is given in the paper given below.how should i utilize it?

https://www.researchgate.net/publication/312876187_Numerical_investigation_into_a_surface_plasmon_resonance_sensor_based_on_optical_fiber_microring

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[Guilin Sun]

I did not find description of collimated beam coupling to fiber in the paper. Usually the fiber is long enough to do two simulations:
1: coupling coefficient from the light source (mostly from a semiconductor laser or  a laser beam through a microcope object lens with numerical aperture NA).

2: the sensor, SPP part with analyte.

I would suggest you simulate the sensor first. You may also need to check if the structured SPR device creates the reflection in to the fundamental mode or with some higher order modes.

 

 

[jannatul nayem]

Thank you for your reply.

I did not understand how to do simulation according to option 1.do i need to use beam source with thin lens or something else?And if i follow the second one how would i do it.It would be great if you tell me in detail.in general how long the optical fiber is to do simulation?

In the paper information of collimated source is given here

[Guilin Sun]

We need to separate the two simulations in different posts.

for fiber coupling, if you think it is good to use collimated light, you can. But we recommend using NA beam. You can test.

Lumerical does not have a fiber coupling exmaple:

https://optics.ansys.com/hc/en-us/articles/360043165394-Fibers-list-of-examples

but we have edge coupler example:

https://optics.ansys.com/hc/en-us/articles/360042305354-Edge-coupler

so you can refer the fiber structure.

 

For the sensor part, as long as you have the desired source inside the fiber, you can simulate it either using FDTD or EME, depending on your preference and computer. I would suggest that you first identify the SPP mode.