Narrow bandwidth laser array system
AssigneeHughes Aircraft Company
InventorRonald R. Stephens
Life of this patent
Estimating the term…
Abstract
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.
Claims35
A narrow bandwidth laser array system, comprising:
- an array of optically isolated, independent lasers having predetermined emission spectra,
- a reflection element that is at least partially reflective of radiation within said emission spectra,
- optical transmission means for directing at least a portion of the optical outputs from said lasers onto said reflection element, and for directing a vertically dispersed portion of the laser radiation reflected from said reflection element back onto said laser array wherein the bandwidth of said portion is limited by the height of said lasers so as to substantially reduce the bandwidth of the output radiation from said laser array.
A narrow bandwidth laser array system, comprising:
- an array of optically isolated independent lasers having predetermined emission spectra,
- an optical reflection element that is reflective of radiation within said emission spectra,
- a beam splitter for transmitting as an output beam a portion of the light from said lasers and for redirecting to said reflection element other light from said lasers, and for reflecting back to said lasers from said reflection element a vertically dispersed portion wherein the bandwidth of said portion is limited by the height of said lasers so as to substantially reduce the bandwidth of the output radiation emitted from said laser array,
- a first lens means for collimating light from said lasers for redirection by said beam splitter onto said reflection element, and
- a second lens means for focusing light from said lasers that is redirected by said beam splitter onto said reflection element, and for collimating light reflected from said reflection element onto said beam splitter.
A narrow bandwidth laser array system, comprising:
- an array of optically isolated, independent lasers having predetermined emission spectra,
- an optical reflection element That is partially transmissive and partially reflective of radiation within said emission spectra, and
- first and second lens means for directing light emitted from said lasers onto said reflection element and for directing a vertically dispersed portion of the light reflected back from said reflection element along a return path to said lasers, wherein the bandwidth of said portion is limited by the height of said lasers, so as to substantially reduce the bandwidth of the output radiation emitted by said laser array, the light transmitted by said reflection element providing an output from said system.
A narrow bandwidth laser array system, comprising:
- an array of optically isolated, independent laser elements having predetermined emission spectra,
- an optical reflection element that is reflective of radiation within said emission spectra,
- a first lens means in the path of the light emitted from said lasers for processing a portion of said light into an output beam,
- means for redirecting light from said laser element that has been transmitted through said first lens means but is not included in said output beam, and
- a second lens means that is arranged to focus said redirected light onto said reflection element so that it is reflected back to the lasers from which said output beam is obtained to substantially reduce the bandwidth of the output radiation emitted by said laser elements.
Dependencies are inferred from the claim text.