Apparatus for reducing spacing between a plurality of parallel, spaced apart plane-polarized laser-radiation beams delivered by a stack of laser-diode bars includes a ninety degree polarization rotator, and a compound prism including a total reflecting surface an internal polarization-selective surface parallel to each other. The polarization-selective surface is highly transmissive for radiation plane-polarized in one polarization orientation and highly reflective for radiation plane-polarized at ninety degrees to that orientation. The polarization rotator rotates the polarization of a portion of the beams. The beams are transmitted through the compound prism with the portion of polarization-rotated beams following a different path through the prism from that of the beams that are not polarization rotated. The beams exit the prism with spacing therebetween one-half of the spacing between beams entering the prism.

Apparatus for reducing spacing of beams delivered by stacked diode-laser bars

Arrangements for combination and fast-axis alignment of fast-axes of diode-laser beams are disclosed Alignment arrangements include providing each diode-laser with a corresponding alignable fast-axis collimating lens, providing individually alignable mirrors for steering an re-orienting beams from each diode-laser, and providing single diode-laser slab-modules in which the diode-laser beams can be pre-aligned to a common propagation-axis direction, and in which edges and surfaces of the slabs can be used to align the fast and slow-axes of the beams Beam combination methods include combination by dichroic elements, polarization-sensitive elements, and optical fiber bundles

High power and high brightness diode-laser array for material processing applications

A method of coupling laser-radiation into an optical fiber includes providing a stack of diode-laser bars and first and second parallel mirrors, the second mirror is selectively reflective only for one polarization plane of the laser-radiation. Each of the diode-laser bars includes at least two spaced-apart diode-laser emitters each emitting a plane-polarized beam of laser-radiation having a fast axis and a slow axis. The laser-radiation beams are collimated in the fast axis by a cylindrical lens located in front of each bar. In one arrangement the polarization orientation of one collimated beam from each diode-laser is rotated by 90 degrees and transmitted through the selectively-reflective mirror. The other collimated beam from each diode-laser bar is reflected onto the selectively-reflective mirror by the first mirror and reflected from the selectively-reflective mirror such that the reflected beam combines with the transmitted beam to form a combined beam. As many combined beams are formed as there are diode-laser bars in the stack. These combined beams are focused into an entrance face of the optical fiber.

Method and apparatus for coupling radiation from a stack of diode-laser bars into a single-core optical fiber

The invention relates to an optical arrangement for symmetrizing the radiation of a plurality of laser diodes that are arranged adjacently to each other and on top of each other, in a fixed manner relative to each other. The output radiation of each laser diode is unsymmetrical in relation to a first direction (the y axis) and a second direction (the x axis) which are perpendicular in relation to each other. The inventive optical arrangement is particularly for use for symmetrizing the radiation of laser diode bars that are stacked on top of each other, forming a laser diode stack. A plurality of microcylindrical lens units (2a, 2b, 2c) with sufficient isoplanacy are arranged in such a way that they are tilted about the optical axis (the z axis) of the designated linear array of laser diodes, collimate the output beam bundles of the individual laser diodes of the designated linear array of laser diodes in direction y, deviating said output beam bundles to different degrees and separating them as they do so. The bundles (8) output from the laser diodes that are arranged on top of each other in direction y coincide at a set distance. A directional element (3) is mounted downstream of the microcylindrical lens unit (2a, 2b, 2c). This directional element diverts the beam bundle (8) of the individual laser diodes that are arranged adjacently to each other in direction x with different angles of deflection respectively, so that the central points of the individual beam bundles (8) coincide at a set distance. A redirecting element (5) is located at a distance behind the directional element (3) and compensates the different angles of deflection of the beam bundles (8) introduced by the directional element (3) in the plane xz.

Optical arrangement for symmetrizing the radiation of two-dimensional arrays of laser diodes

By dividing at least the part of the correction optics of at least one row of emitter elements, ie the part acting as the fast axis collimator, into several segments, the degradation of beam quality at the focus, especially the widening of the focus, which is caused by the nonconformities between the diode laser bars, or between the row of emitter elements, and the correction optics, can be effectively prevented

Optical arrangement for the use during a laser diode arrangement as well as laser diode arrangement with such an optical arrangement

An optical arrangement is provided for balancing the beam of one or more high-power diode lasers (HP-DL) arranged one above another. The beam, which is known to diverge very differently in the direction of the pn junction and perpendicular to the pn junction of the emitters of an HP-DL arranged in a row is imaged at a point with high power density and high beam quality the arrangement. Present for this purpose are optical devices which spread out the radiation in a mutually offset fashion in the direction of the pn junction while the radiation is superimposed perpendicular to the pn junction.

Optical arrangement for balancing the beam of one or more high power diode lasers arranged one above another

Die bekanntlich in Richtung des pn-Ubergangs und senkrecht zum pn-Ubergang, der in einer Reihe angeordneten Emitter eines HL-DL, stark unterschiedlich divergente Strahlung, wird mittels der erfindungsgemasen Anordnung in einen Punkt mit hoher Leistungsdichte und hoher Strahlqualitat abgebildet. Zu diesem Zweck sind optische Mittel vorhanden, welche die Strahlung in Richtung des pn-Ubergangs zueinander versetzt auffachert, wahrend die Strahlung senkrecht zum pn-Ubergang uberlagert wird.

Optische anordnung zur symmetrierung der strahlung eines oder mehrerer übereinander angeordneter hochleistungsdiodenlaser

According to the inventive system, the highly diverging beam of a high-power diode laser emitter arranged in line in the direction of a pn junction and perpendicular to the pn junction is projected at a point with high power density and high beam quality. To this end, optical means are provided that spread the beams in the direction of the pn junction in a staggered manner in relation to each other while the beam is superimposed perpendicular to the pn junction.

Michael Nickel

Papers

Optical arrangement for balancing the beam of one or more high power diode lasers arranged one above another

Optische anordnung zur symmetrierung der strahlung eines oder mehrerer übereinander angeordneter hochleistungsdiodenlaser

Optical system for symmetrizing the beam of one or more superimposed high-power diode laser