Publications by authors named "Kalaga V Madhav"
We present an experimental study on our first generation of custom-developed arrayed waveguide gratings (AWG) on a silica platform for spectroscopic applications in near-infrared astronomy. We provide a comprehensive description of the design, numerical simulation and characterization of several AWG devices aimed at spectral resolving powers of 15,000-60,000 in the astronomical H-band. We evaluate the spectral characteristics of the fabricated devices in terms of insertion loss and estimated spectral resolving power and compare the results with numerical simulations.
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- The study presents initial results from a four-telescope integrated optics discrete beam combiner (DBC) tested at the William Herschel Telescope, designed to improve astronomical observations.
- The DBC, created using ultrafast laser inscription on a single substrate, processes light from stars like Vega and Altair at the H-band (1.6 µm) while utilizing a deformable mirror for efficient light injection.
- The results indicated that the measured visibility amplitudes and closure phases were affected by a significant dispersion from expected values, primarily due to a low signal-to-noise ratio, marking an initial step toward validating DBC for long-baseline interferometry.