Demonstration of a speckle nulling algorithm and Kalman filter estimator with a fiber injection unit for observing exoplanets with high-dispersion coronagraphy

High-dispersion coronagraphy (HDC) combines high contrast imaging techniques with high spectral resolution spectroscopy to observe exoplanets and determine characteristics such as chemical composition, temperature, and rotational velocities. It has been demonstrated in lab that with monochromatic light, a fiber injection unit (FIU), in which an optical fiber is used to couple to light from the exoplanet, could be used to direct exoplanet light to a high-resolution spectrograph, with robust performance and speckle suppression that exceeds conventional image-based speckle nulling. We now demonstrate in lab a FIU based speckle nulling scheme with a Kalman filter estimator. We currently find that speckle nulling with a Kalman filter is more stable and outperforms traditional speckle nulling by 10% in suppression in the presence of white detector noise.