AbstractThe increasing number of spectral survey telescopes that are soon commissioned for exploring the universe will confront us with many new challenges on the use of optical fibers. A fiber-switching problem for telescope's terminal instrument is as important as a well-known problem of positioning fibers on telescope's focal plane. For a modern survey telescope, it generally feeds several terminal instruments with different functions. According to the observation, these instruments are seriously in need of switching fiber-link with telescope as soon as possible. A kind of multi-fiber coupling plugs introduced in this paper will work for switching fiber-link between Multi-object Exoplanet Search Spectral Interferometer (MESSI) and low resolution spectrograph at Guoshoujing telescope (LAMOST). It includes an inserter, a receptor and a socket in general. The number of simultaneously coupling fibers is up to 25 per group, and any broken fiber in a single plug can be replaced by a new standard one soon without wasting entire fiber bundle. In addition, Most of mechanical part can also be individually replaced when a normal loss happens after a long working time. The related test result is given in detail, including the machining precision and coupling efficiency.
New model of the fiber coupling efficiency of a partially coherent Gaussian beam in an ocean to fiber link
