  Integrated photonic devices have become pivotal elements across most research
fields that involve light-based applications. A particularly versatile category
of this technology are programmable photonic integrated processors, which are
being employed in an increasing variety of applications, like communication or
photonic computing. Such processors accurately control on-chip light within
meshes of programmable optical gates. Free-space optics applications can
utilize this technology by using appropriate on-chip interfaces to couple
distributions of light to the photonic chip. This enables, for example, access
to the spatial properties of free-space light, particularly to phase
distributions, which is usually challenging and requires either specialized
devices or additional components. Here we discuss and show the detection of
amplitude and phase of structured higher-order light beams using a multipurpose
photonic processor. Our device provides measurements of amplitude and phase
distributions which can be used to, e.g., directly distinguish light's orbital
angular momentum without the need for further elements interacting with the
free-space light. Paving a way towards more convenient and intuitive phase
measurements of structured light, we envision applications in a wide range of
fields, specifically in microscopy or communications where the spatial
distributions of lights properties are important.
