The Pigtailed 2x2 Fiber-optic Rotary Joints have 2 optical channels with static side pigtailed with 1m long FC-connectorized optical fibers. Due to the space constriction with 2 FC connectors side by side, we have chosen to use two M3 receptacles on the rotating side. The patch cords have a 200 or 400 μm core, 0.37 or 0.57 NA optical fibers, and a robust jacket. The optical channels follow separate paths and have low loss,  minimum possible signal variations during rotation, and no crosstalk.

Inside the joints are high NA aspheric lenses to match high NA optical fibers of LED or Ce:YAG light sources used for fiber photometry. Aspheric lenses are optimized for 530 nm but perform reasonably well for other wavelengths.

This passive pigtailed fiber-optic rotary joint is intended for fiber photometry experiments involving recordings at two different brain sites/regions of the larger tethered behaving animals like rats.