An apparatus includes an optical Input/Output (I/O) connector, which has a central axis that is mounted in a plane and which is configured to connect to external optical fibers for transferring input optical signals to the apparatus and output optical signals from the apparatus. A first optical ferrule is mounted perpendicularly to the optical I/O connector in the plane, and is configured to transfer the input optical signals from the optical I/O connector to respective optical detectors. A second optical ferrule is mounted perpendicularly to the optical I/O connector in the plane, and is configured to transfer the output optical signals from respective optical emitters to the optical connector. A light rotation module is configured to bend and transfer the input and output optical signals between the optical I/O connector and the perpendicularly-mounted first and second optical ferrules.