# MATLAB Center Wavelength of Fiber Bragg Grating Filter

1. Feb 16, 2016

### spyrius

I would like to locate the center wavelength of a FBG notch filter in MATLAB, but I'm having trouble getting an answer within 0.01nm of the correct wavelength.

So far I've tried using a quadratic fit with MATLAB, but that is too dependent on the amount of data points to the left and right of the notch. The location of the peak is also not correct, because the filter is only made up of ~10 discrete data points, and the highest/lowest one is not necessarily the center.

Any help would be appreciated.

2. Feb 22, 2016

### Greg Bernhardt

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

3. Feb 23, 2016

### Staff: Mentor

Can you fill us in a bit more on what you're trying to do? Are the 10 points you mentioned points taken from the graph you showed? If so, it's entirely possible that with such a small data set, you could completely miss the valley (it's not a peak) at 1.5458 $\mu$m.