Semiconductor laser arrangement and projector

Patent metadata

Field	Value
Publication number	US-10270225-B2
Application number	US-201615773162-A
Country	US
Kind code	B2
Filing date	Nov 2, 2016
Priority date	Nov 2, 2015
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

A semiconductor laser arrangement and a projector are disclosed. In an embodiment the semiconductor laser arrangement includes at least two electrically pumped active zones, each active zone configured to emit laser radiation of a different emission wavelength and a semiconductor-based waveguide structure, wherein the active zones are electrically independently operable of one another, wherein the active zones optically follow directly one another along a beam direction and are arranged in a descending manner with regard to their emission wavelengths, wherein at least in a region of a last active zone along the beam direction, a laser radiation of all active zones jointly runs through the waveguide structure, wherein at least the last active zone comprises a plurality of waveguides which are stacked one above the other and are oriented parallel to one another, wherein one of the waveguides is configured for the radiation emitted by the last active zone.

First claim

The invention claimed is:

1. A semiconductor laser arrangement comprising:
at least two electrically pumped active zones, each active zone configured to emit laser radiation of a different emission wavelength during operation by recombination of charge carriers in at least one semiconductor material; and
a semiconductor-based waveguide structure,
wherein the active zones are electrically independently operable of one another,
wherein the active zones follow directly one another optically along a beam direction along a straight line and are arranged in the semiconductor laser arrangement in a descending manner with regard to their emission wavelengths,
wherein at least in a region of the last active zone along the beam direction, a laser radiation of all active zones jointly runs through the waveguide structure,
wherein at least the last active zone comprises a plurality of waveguides which are stacked one above the other and are oriented parallel to one another, the waveguides being part of the waveguide structure,
wherein one of the waveguides is configured for the radiation emitted by the last active zone, the at least one active zone that precedes the last active zone radiates into a different one of the waveguides than the last active zone,
wherein the waveguides which are assigned to the last active zone, taken together in the direction perpendicular to the beam direction and viewed in cross-section, have an extent of at most 10 μm, and
wherein the waveguide structure is configured to guide the laser radiation generated during operation in the active zones by internal total reflection so that the waveguides in each case comprise a core material having a high refractive index for the corresponding laser radiation and the core material is surrounded by at least one layer made of a material having a lower refractive index.

2. The semiconductor laser arrangement according to claim 1 , wherein each of the active zones is accommodated in a separate edge-emitting semiconductor laser chip.

3. The semiconductor laser arrangement according to claim 2 , wherein precisely one of the semiconductor laser chips has exactly one waveguide.

4. The semiconductor laser arrangement according to claim 2 ,
wherein at least a last semiconductor laser chip comprises a plurality of stacked waveguides which are aligned parallel to one another,
wherein the stacked waveguides are part of the waveguide structure,
wherein one of the waveguides is provided for the active zone of the last semiconductor laser chip,
wherein the at least one semiconductor laser chip preceding the last semiconductor laser chip radiates into a different one of the waveguides than the active zone of the last semiconductor laser chip, and
wherein the waveguides of the last semiconductor laser chip, taken together in the direction perpendicular to the beam direction and viewed in cross-section, have an extent of at most 4 μm.

5. The semiconductor laser arrangement according to claim 2 ,
wherein a distance between at least one of radiation exit surfaces or facets of adjacent semiconductor laser chips is at most 50 μm, and
wherein a space between the adjacent semiconductor laser chips is free of a waveguide for the laser radiation.

6. The semiconductor laser arrangement according to claim 1 ,
wherein all active zones are produced on a common growth substrate, and
wherein a relative difference between at least two of the emission wavelengths is at least a factor of 1.05.

7. The semiconductor laser arrangement according to claim 6 , wherein all active zones, along a growth direction of a semiconductor layer sequence with the active zones, are stacked one above the other so that no two active zones are located at the same height in the direction parallel to the growth direction.

8. The semiconductor laser arrangement according to claim 1 , wherein a number of the waveguides, which are assigned to the respective active zone in the direction parallel to a growth direction of a semiconductor layer sequence, increases in a strictly monotonic manner along the beam direction.

9. The semiconductor laser arrangement according to claim 6 , wherein precisely one of the waveguides extends over all active zones with a constant extent and along a straight line.

10. The semiconductor laser arrangement according to claim 1 , wherein, between adjacent active zones and along the beam direction, at least one of a wavelength-selective mirror or a wavelength-selective optical grating are located.

11. The semiconductor laser arrangement according to claim 1 , wherein the waveguide structure essentially consists of one or more semiconductor materials.

12. The semiconductor laser arrangement according to claim 1 , wherein the semiconductor laser arrangement is free of phosphors and free of optically pumped laser structures.

13. The semiconductor laser arrangement according to claim 1 , wherein the semiconductor laser arrangement comprises one active zone for generating blue light, one active zone for generating green light and one active zone for generating red light.

14. The semiconductor laser arrangement according to claim 1 , wherein the semiconductor laser arrangement comprises one active zone for generating blue light or ultraviolet radiation and one active zone for generating near-infrared radiation.

15. The semiconductor laser arrangement according to claim 1 , wherein for each one of the different emission wavelengths an own plane parallel to a support is present, in which planes the respective radiation is guided, the planes have mutually different distances to the support.

16. A projector for projecting variable color images comprising:
a semiconductor laser arrangement according to claim 1 ; and
an imaging optical system,
wherein the projector is designed to emit laser radiation having an average luminous flux of at least 10 lm, and
wherein the semiconductor laser arrangement takes a volume of at most 10 mm×3 mm×3 mm in the projector.

Assignees

• Osram Opto Semiconductors Gmbh

Inventors

• Stojetz Bernhard
• Lell Alfred
• Eichler Christoph
• Löffler Andreas
• Somers André

Classifications

• H01S5/2031

  characterized by special waveguide layers, e.g. asymmetric waveguide layers or defined bandgap discontinuities · CPC title

• H01S5/426

  Vertically stacked cavities · CPC title

• H01S5/2018

  Optical confinement, e.g. absorbing-, reflecting- or waveguide-layers · CPC title

• H01S5/1028

  Coupling to elements in the cavity, e.g. coupling to waveguides adjacent the active region, e.g. forward coupled [DFC] structures · CPC title

• H01S5/02252

  Electricity · mapped topic