Versatile mid-resolution fiber-fed spectrograph on Subaru/SCEXAO for interferometry and photonic devices spectroscopy in the visible

Single-mode (SM) fiber-fed spectrographs offer several advantages such as spatial filtering of the wavefront, high spectral resolution, stability and flexibility in instrument design. We present the integration and applications of a SM fiber-fed spectrograph of resolving power ~4000 at 635nm on the extreme adaptive optics platform of the Subaru telescope (SCExAO). The spectrograph disperses the outputs of a 19-port visible photonic lantern (PL), a high throughput fiber device that efficiently converts a multimode waveguide to several SM waveguides. With this setup and downstream of extreme adaptive optics, PLs enable high throughput and high resolution spectroscopy. We report on the analysis of the dispersed output flux for image reconstruction of binary sources. The spectrograph also improves the resolution of the Fiber Imager foR a Single Telescope (FIRST), a visible spectro-interferometer providing high-precision, high-angular-resolution spatial coherence measurements. We report on the sensitivity performance of the upgraded instrument on SCExAO.