Sdl Inc.

Derek W Nam

Robert G Waarts

David F Welch

Donald R Scifres

Jo S Major

Robert J Lang

Jonas Webjorn

A harmonic generator laser system which features a distributed Bragg reflector (DBR) or distributed feedback (DFB) tunable diode laser coupled to a quasi-phase matched (QPM) waveguide of optically nonlinear material. Tuning of the DBR laser may be achieved either thermally or via current injection, or both, halving the wavelength of a red laser into the visible blue spectral band. Thermal tuning may provide a coarse tuning adjustment, while injected current may provide fine tuning accessible to a user. Separately or in combination with current tuning, a modulation signal may be applied to the DBR laser for achieving an intensity modulated or a pulsed output. In another embodiment, modulation may be achieved by frequency modulation of the laser. A very compact tunable blue laser is formed. In yet another embodiment a double clad fiber amplifier is disposed between the tunable laser and the waveguide. The fiber amplifier is pumped by a high power laser, while the core guides light to be frequency doubled in the nonlinear material from a continuously tunable laser.

Tunable blue laser diode

Several embodiments are described for induced electric field or E-field poling of QPM nonlinear crystal materials, such as LiNbO.sub.3, LiTaO.sub.3 and KTP, utilizing approaches which, for the most part, avoid the necessity of depositing or otherwise forming a series of spatially disposed conductive electrodes on one surface of the nonlinear crystal material. E-field poling is accomplished by applying a high voltage electric field in excess, for example, in the range of several kilovolts per cm to several 100 kilovolts per centimeter, at room temperature to provide inverted domains in a pattern of continuously alternating domains corresponding to the regions formed on the first z surface of the crystal. The employment of single, planar-applied liquid electrodes is preferred eliminating any necessity of forming and removing previously formed metal electrodes in the poling process.

Periodic electric field poled crystal waveguides

A harmonic generator laser system which features a distributed Bragg reflector (DBR) or distributed feedback (DFB) tunable diode laser coupled to a quasi-phasematched (QPM) waveguide of optically nonlinear material. Tuning of the DBR laser may be achieved either thermally or via current injection, or both, halving the wavelength of a red laser into the visible blue spectral band. Thermal tuning may provide a coarse tuning adjustment, while injected current may provide fine tuning accessible to a user. Separately or in combination with current tuning, a modulation signal may be applied to the DBR laser for achieving an intensity modulated or a pulsed output. In another embodiment, modulation may be achieved by frequency modulation of the laser. A very compact tunable blue laser is formed. In yet another embodiment a double clad fiber amplifier is disposed between the tunable laser and the waveguide. The fiber amplifier is pumped by a high power laser, while the core guides light to be frequency doubled in the nonlinear material from a continuously tunable laser.

A compact semiconductor laser light source providing short wavelength (ultraviolet, blue or green) coherent light by means of frequency doubling of red or infrared light from a high power diode heterostructure. The high power diode heterostructure is a MOPA device having a single mode laser oscillator followed by a multimode, preferably flared, optical power amplifier. A tunable configuration having an external rear reflector grating could also be used. A lens could be integrated with the MOPA to laterally collimate the light before it is emitted. Straight or curved, surface emitting gratings could also be incorporated. An astigmatism-correcting lens system having at least one cylindrical lens surface is disposed in the path of the output from the MOPA to provide a beam with substantially equal lateral and transverse beam width dimensions and beam divergence angles. A nonlinear optical crystal or waveguide is placed in the path of the astigmatism-free symmetrized beam to double the frequency of the light. Single pass or multipass configurations with reflectors could be used, as well as external resonator and segmented, periodically poled waveguide configurations.

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Sunnyvale, CA, United States of America

Derek W Nam