Light path along a circular arc and transmission of a signal between two units rotating relative to each other

An optical device comprising a light path for guiding a light beam along a circular arc,

• wherein the light path comprises at least one light path segment comprising a plurality of light path elements arranged tangentially along the light path, each of the light path elements being at least partially limited in a radial direction by a respective first interface,
• wherein the first interfaces of a respective light path segment are each configured to reflect at least light incident from the light path at an angle of incidence greater than a predetermined angle onto the respective first interface to keep a light beam propagating along the light path in a direction of travel predetermined for the respective light path segment on the light path;
• and
• wherein, for each of the first interfaces of the plurality of light path elements, a first tangential end of the respective first interface is spaced radially further apart from the center of the circle of the circular arc than a second tangential end of the respective first interface, wherein a ratio between an extension of each of the first interfaces in a tangential direction along the circular arc and a distance between the first tangential end of a first one of the first interfaces and the second tangential end of a second one of the first interfaces neighboring the first tangential end of the first one of the first interfaces, the distance being measured in the tangential direction along the circular arc, is at least 5:1.