In this work a compact green laser light source is presented based on a single-pass second harmonic generation (SHG) in
non-linear material. The green light source consists of a distributed feedback (DFB) laser with a monolithically
integrated power amplifier (PA) and a periodically poled lithium niobate (PPLN) crystal with a ridge waveguide. To
achieve the smallest size and to reduce the number of parts to be assembled, a direct coupling approach is implemented
without using any lens. The waveguide of the laser is bent and the facet of the crystal is tilted and AR-coated in order to
reduce undesired reflections and to increase the stability of operation. By varying the injection current of the amplifier
the infrared output power of the laser changes proportionally. The wavelength remains stable during current variation
and in that way the green optical output power can also be modulated. No additional external modulator is required for
the generation of distinct green light levels. At a wavelength of 530 nm, a green optical output power of more than
35 mW is achieved for injection currents of 93 mA and 400 mA through the DFB section and amplifier section
The authors have developed a new compact integration concept for a green laser emitter. Compact green light sources
are of great interest for several applications such as in spectroscopy and mobile displays. The requirements for such
sources are low noise, high-frequency modulation capability, compactness, reliability, low power consumption, and low
cost. The developed green-light source fulfils these requirements due to its dense integration while allowing larger
tolerances within the fabrication processes. The green-laser emission of 30 mW is generated using second harmonic
generation (SHG) in a nonlinear crystal. As pumping light source, a reliable GaAs semiconductor laser diode with an
emission wavelength at 1060 nm has been developed. This
single-wavelength distributed feedback (DFB) laser diode has
a sidemode suppression ratio better than 40 dB and an optical power of up to 325 mW. The SHG device is a periodically
poled lithium niobate (PPLN) waveguide. The 1060 nm pump light is directly coupled to the passive nonlinear
waveguide. To enable the precise operating temperature conditions for DFB and PPLN, both components are mounted
on separate temperature controllers. As confirmed also by
thermo-mechanical simulations, the presented compact,
reliable integration of green-light emitter enhances the overall yield by introducing a fabrication process tolerant
We present a compact green light emitter for laser displays and focus on the pump source for a SHG waveguide in
single-pass configuration. The developed pump source has a RW-structure consisting of three sections: a DFB, a spacer
and an amplifier section. The optical output power is 305mW for currents of 120mA and 400mA in DFB and amplifier
section. The control of the current in the amplifier section allows a modulation of the output power from 5mW to
305mW. Spectral characteristics as well as measured beam divergence are well suited for pumping SHG waveguide
crystals. Results on the hybrid 530nm emitter are summarized.
A photo-convertible protein is found in several species of the coral genus <i>Lobophyllia</i>. Its green fluorescence is
converted to red by irradiation in the 340-400nm range. It also exhibits a wider range of photo-reactive properties,
including a reversible photo-bleaching when in a partially-converted state. We present data on its behaviour under
single and multiphoton irradiation.
Experimental results on RW and BA DFB lasers emitting at 785 nm suitable for Raman spectroscopy are presented.
Optical spectra of the RW DFB laser reveal single mode operation with a side-mode suppression ratio of more than 45 dB at optical output powers up to 163 mW. A reliable operation of more than 8800 h of these devices is demonstrated. Within a spectral width of 0.6 nm, more than 99.9% of 1.1 W optical power of the BA DFB laser emitting at 785 nm are included. Raman measurements with RW and BA DFB lasers as excitation light sources and polystyrene as a test sample are presented. At an output power of 1.1 W of the BA device the integration time for the Raman measurement could be reduced to 50 ms.
A master-oscillator power-amplifier system at λ=1083 nm with 5.3 Watt output power and a narrow spectral linewidth was realised. The master oscillator was a distributed Bragg reflector (DBR) laser with a 3-μm wide ridge waveguide (RW) and a total length of 2 mm. The power amplifiers were a 4 mm long antireflection coated tapered laser diodes with 500 μm or 1000 μm long straight RW sections. At a temperature of 40<sup>o</sup>C and an injection current of 160 mA, the DBR laser had a wavelength of 1083 nm. The emitted light of the DBR laser was focused into the tapered amplifier with a seed power of up to 36 mW. At 10<sup>o</sup>C and at a current through the tapered amplifier of 8.6 A, a maximum output power of 5.3 W was measured. Over the full operating range single longitudinal mode operation at a wavelength of λ=1083 nm was maintained with a side mode suppression ratio better than 35 dB. The vertical far field angle was below 22<sup>o</sup> (FWHM).