Michelson interferometer dimensions

[malak]

hi
i want to design michelson interferometer device for measuring small distance movement
i am using laser diode with a wavelength 635 nm and power 3 mw
can anyone tell me how can i decide the dimensions (from source to beam splitter , for beam splitter to fixed mirror , from beam splitter to detector )
knowing that the moving mirror should be placed 35 mm from beam splitter (the tested object position )
also how can i choose the fixed mirror dimensions ?
regards

 

[theo1234901]

the equation used in michelson interferometer is

d = mλ/2

so then I will put my fixed mirror also at 35 mm, if there are a displacement in the object there will be a differences in the amount of fringes