A non-reciprocal optical device for interconnecting single mode optical fiber waveguides so that a light beam can pass between the fibers in a forward direction but a reverse beam, such as might be caused by unwanted reflections, is displaced away the input fiber, includes a focussing lens unit and at...http://www.google.es/patents/US5588078?utm_source=gb-gplus-sharePatente US5588078 - Non-reciprocal optical waveguide coupling device
