Spectra-physics Gmbh

Opto Power Corporation

Hans-Georg Treusch

Guido Bonati

Raman Srinivasan

An assembly for providing a concentrated, vertically stacked array of laser beams from a horizontally offset array of electrically serially-connected metallic microchannel heat sinks each bearing a laser diode bar. The heat sinks are mounted on horizontally offset planes of the manifold which has coolant channels serving adjacent heat sinks that are separated from each to increase the electrical resistance of the fluid path between adjacent ones of said heat sinks. Stepped optical deflectors re-arrange the horizontally emitted laser beams into vertical stack.

Stepped manifold array of microchannel heat sinks

A laser bar is soldered to a conventional microchannel copper heat sink whose coefficient of thermal expansion (CTE) is locally modified in the area where the laser bar is soldered to better match the CTE of the laser bar. A strip of ceramic material having a CTE lower than that each of the laser bar and of the copper heat sink is soldered to portions of the metallic heat sink located adjacently to the surface area on which the laser bar is located. The inclusion of the ceramic strips enables a laser bar having a nominal CTE of 6.6&#xd7;10/K, to be soldered directly to a copper heat sink having a nominal CTE of 16.5&#xd7;10/K without incurring thermal distortions at the interface that would limit the useful life of the laser bar.

CTE compensation of semiconductor laser bars

A laser diode stack includes a serially connected plurality of laser diode bars mounted on heat sinks. Connected in parallel with each laser diode is a respective safety diode which has a higher band gap than its associated laser diode. The safety diode remains nonconductive so long as the associated laser diode is operational. Should the laser diode fail in an open circuit condition, the respective safety diode responds to the open circuit voltage to restore continuity to the serially connected chan of laser diodes.

Reliable diode laser stack

A stack of parallel but laterally separated laser beams emitted from a pair of laterally separated laser diode bars are focused into a single vertical plane through the use of an interleaved array of stacked, angular glass plates. Successive plates oppositely refract laser beams from successive radiating levels of the stacks of laser bars so that beams emerging from the glass plates lie in the same vertical plane, thereby overcoming the lateral displacement among beams emerging from the laser bars.

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Tucson, AZ, United States of America

Hans-Georg Treusch