Fast-switching frequency-converted laser light source for display applications

We report a passively Q-switched two-component visible laser light source based on frequency conversion. The device consists of a monolithic single transverse mode ridge-waveguide infrared laser diode and a waveguide-type periodically poled magnesium oxide doped lithium niobate crystal for second harmonic light generation. An integrated 45-degree folding mirror and a coupling lens are formed by etching on opposite sides of the monolithic gallium arsenide -based laser diode for coupling the infrared emission into the waveguide-type nonlinear crystal for efficient single pass frequency conversion. Passively Q-switched operation is realized by an integrated electro-absorber section coupled with the in-plane multi-quantum well gain structure. Stable high-repetition rate self-pulsating operation was achieved by reverse-biasing the electro-absorber section and reduced speckle visibility of the second harmonic light was observed when compared to continuous-wave operation of the same laser.