| 摘要 |
A waveguide coupler comprises a curved end reflector mirror that images a waveguide exit back into the waveguide with an essentially exact reproduction of the waveguide output intensity distribution. The coupler also comprises a lens disposed near the waveguide exit at a point between the exit and the mirror, the lens providing a phase compensation to the beam passing therethrough such that the phase of the beam returned to the waveguide matches that of the exiting beam. Thus, coupling losses due to clipping of the returned beam at the exit/entrance to the waveguide bore and coupling losses due to a mismatch of the returning field phase to that of the waveguide mode are made essentially zero. Other embodiments of the coupler are presented wherein the phase compensating lens is positioned at locations other than adjacent to the waveguide exit, or wherein no inversion of the imaged field field distribution occurs, or wherein the beam is not caused to be focused at the center of a lens, or wherein one waveguide is coupled to another waveguide having a similar sized or a dissimilar sized bore.
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