| 摘要 |
A spectral narrowing of the output bandwidth from a laser array is obtained by feeding back to the array a portion of its emitted light, while outputting the remainder of the light emitted from the array. An optical system to accomplish this preferably includes a pair of lenses, together with a diffraction grating that can be positioned either in-line with the laser array and lenses, or in a side-arm along with one of the lenses. The lenses can be set up so that light from each laser element is fed back either to itself, or to a symmetrically located element on the opposite side of the system axis. For a multi-lobe output from the laser array, one of the lobes is used for feedback and the others as outputs, resulting in a narrowing of the output angular divergence as well as of the output bandwidth.
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