A method and apparatus for operating an optical rotating joint (2); comprising: routing optical signals through an optical rotating joint (2) by using a first optical circulator (64) on a first side of the optical rotating joint (2) to receive an optical signal and direct the optical signal onward to a first side of the optical rotating joint (2), and using a second optical circulator (93) on a second side of the optical rotating joint (2) to receive the optical signal from the second side of the optical rotating joint (2) and direct it onwards. The signals may be sensor control signals or sensor output signals to/from a plurality of sensors (26, 28, 30), for example camera sensors. The apparatus may further comprise one or more wavelength division multiplexers (68, 94) and/or wavelength division demultiplexers (66, 95).