(I realize that my answer to this question has not uploaded correctly Yesterday.  I will attempt a second time to answer, now.)

Let say that you have a Fabry-Perot (FP) design:

(mHmL)^5 (mLmH)^5 on a low index substrate.

with m=1, this is a classic FP with a halfwave low-index spacer and a narrow transmittance peak at Lambda, at the center of a stopband (with low transmittance).  Then for m=3,5,7..., you should still see a narrow transmittance peak at Lambda, within a narrower and narrower stopband;  and for m=2,4,6..., the narrow transmittance peak at Lambda should disappear (it will be shifted to another wavelength).

Dear Daniel Thank you for the answer. Actually, I am designing my filter at mid-IR center wavelength at 4.67 microns. And I realised that at this wavelength it is possible to design the filter at the specified wavelength and layer thicknesses around 1 microns. 

Last time I was unsuccessful due to the fact that at visible center wavelength it is not possible to design such filter with big thicknesses of layers.

Hi Ali.  Happy to see that the design works for you now; it is true that at longer wavelengths, all the layers will be thicker. 

Question:  Will you actually need to fabricate this coating?  If you do, be aware that some optical materials for the mid-IR are not easy to work with (mechanical problems with thick layers, adhesion problems, sensitivity to water, toxicity...)  Good luck!