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MULTI-EMITTER ARRAY LASERS

IP.com Disclosure Number: IPCOM000025480D
Original Publication Date: 1985-Aug-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 63K

Publishing Venue

Xerox Disclosure Journal

Abstract

With 10 emitter array lasers, the far-field radiation pattern often consists of one or two phase-locked radiation lobes near laser threshold. At threshold, this is generally due to emission from five to eight of the lasers. Never do the outer two emitters near the edge of the array reach threshold at the same current as do the centrally located lasers. As the laser power is increased above threshold, these outer edge lasers begin to lase with often a different wavelength and phase relative to the centrally located lasers. This action begins to distort the far-field radiation pattern, and can even cause a new set of phase-locked emitters to lase across the entire width of the array. See, for example, the article of D.R. Scifres et a1 entitled, "Near and Far Field Patterns of Phased Locked Semiconductor Laser Arrays", Applied Physics Letters, Volume 42, No. 6, pp. 495-497, March 15, 1983. This is undesirable behavior if the laser beam is to be collimated or focused.

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XEROX DISCLOSURE JOURNAL

ib1ULTI-EMITTER ARRAY LASERS Donald R. Scifres
Robert D. Burnham
William Streifer

Proposed Classification
U.S. Cl. 372/45 Int. CI. HOls 3/19

With 10 emitter array lasers, the far-field radiation pattern often consists of one or two phase-locked radiation lobes near laser threshold. At threshold, this is generally due to emission from five to eight of the lasers. Never do the outer two emitters near the edge of the array reach threshold at the same current as do the centrally located lasers. As the laser power is increased above threshold, these outer edge lasers begin to lase with often a different wavelength and phase relative to the centrally located lasers. This action begins to distort the far- field radiation pattern, and can even cause a new set of phase-locked emitters to lase across the entire width of the array. See, for example, the article of D.R. Scifres et a1 entitled, "Near and Far Field Patterns of Phased Locked Semiconductor Laser Arrays", Applied Physics Letters, Volume 42, No. 6, pp. 495-497, March 15, 1983. This is undesirable behavior if the laser beam is to be collimated or focused.

However, if 15, 20, 25, 30 or 40 or possibly more lasers in an array are phase locked, the far-field pattern remains stable to much higher output power levels than would be expected from a simple calculation of power per individual emitter. That is, if distortion occurs at 10 mW/emitter for a 10-emitter laser (100 mW total), then the patte...