Devices and methods for passing optical radiation into and out of a body lumen which can include a rotatable ferrule for use in an optical guidewire and methods for using a rotation ferrule. The rotatable ferrule may be either rotatably captured by and free to rotate within a guidewire, or may rotate upon release from a releasable, mechanically stable friction-fit engagement with a guidewire. Sterile interfaces for readily connecting and disconnecting an optical guidewire with and from other optical instrumentation while maintaining the sterility of the guidewire are provided as well as methods for using a sterile interface device. Interface devices can provide either direct or indirect optical and mechanical connection between an optical guidewire and peripheral instrumentation.