Optical fibre pseudo-slits for astronomy

We present a method of assembling a fiber-optic pseudo-slit, inside a custom FC connector. 19 SMFs with 80 μm cladding diameters are arranged in a 1,511 μm pseudoslit, held in the center of a connector ferrule. The SMFs in the pseudo-slit are well positioned and well ordered, having an average core separation in the ‘long’ direction of 79.5 μm and an StDev in the ‘narrow’ direction of 2.68 μm. The nearfield output distribution of the pseudo-slit was measured under 615-730 nm light, finding an FWHM intensity distribution ratio between the two directions of 1 : 21.9. This method could be used with other types of optical connector, allowing pseudo-slits to be used conveniently with existing optical instruments.