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.
We assembled a testbed to study coupling of starlight through atmospheric turbulence via astronomical telescopes into astrophotonic devices. The setup allows for varying the turbulence strength and investigating the effects of different levels of adaptive optics correction on the efficiency of integrated optics. In addition to recording optical powers and wavefront errors, focal plane images are captured from which spots sizes and Strehl ratios are also measured. Novel astrophotonic components proposed as alternatives to conventional optical instruments can therefore be qualified in terms of coupling efficiency and throughput on the testbed before they are tested on the sky.
We will review the development in the last decade of discrete beam combiners (DBC), phase sensors based on the propagation of light in photonic lattices. The latest results on the development of DBC for astronomical applications will be presented, along with a new application for the complete tomography of modes at the tip of a multi-mode fiber. The possible use of the DBC in monitoring and controlling modal instabilities in high power lasers will be discussed.
As compared to single-mode fibers (SMFs), photonic lanterns could ease the coupling of starlight to single-mode astrophotonic instruments. Here we investigate numerically the advantage of using lanterns as compared to SMFs for seeing-limited and low-order adaptive telescopes. We find the turbulence strength below which focal-ratio-matched photonic lanterns provide an average flux per output equal to that of a sole SMF. Lastly, we look into the advantage of having a low-order adaptive optics (AO) as a way of relaxing the demand on the lantern size and complexity.