WFOV and NFOV shared aperture beacon laser

• Main Authors: Chiachi Wang, Michael Sholl
• Format: Patent
• Language: English
• Published: 03.01.2018
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS; TRANSMISSION

Free-space optical communication includes guiding, by focusing optics 230, an optical communication beam 210 emitted from an optical transmitter 220 into a double-clad optical fibre 300. The double-clad optical fibre includes a fibre core 310 with a first numerical aperture NA-1, a first cladding 320 with a second numerical aperture NA-2 where NA-2 >= NA-1, and a second cladding 330. It also includes focussing optics 230 to guide light into the fibre and collimating optics 242 to direct light from the double-clad optical fibre toward an optical receiver of a communication terminal. The second portion 210l, 224 of the optical communication beam is arranged concentrically around the first portion 210h,222 of the optical communication beam which has a higher intensity than the second portion. The focussing optics may direct the first portion of the optical communication beam into the fibre core and the second portion of the beam into the first cladding. The optical transmitter may have a multi-mode source. The fibre core may be perturbed such as by microbending to propagate a low intensity beam portion into the first cladding.