Steffen Lorch

Orange-emitting frequency-doubled GaAsSb/GaAs semiconductor disk laser

We report on an orange-emitting intracavity frequency-doubled semiconductor disk laser based on the material system GaAsSb/GaAs. The infrared fundamental wavelength of λ=1220 nm corresponds to a second-harmonic wavelength of λ=610 nm. The second-harmonic generation is done using a lithium–triborate crystal as the nonlinear material. We have achieved an orange continuous-wave frequency-doubled laser output power of 30 mW in the fundamental transverse mode at a wavelength of λ=610 nm.

Efficient Gallium–Arsenide Disk Laser

Means that may optimize the efficiency of semiconductor disk lasers (optically pumped vertical external-cavity surface-emitting lasers) are discussed: the direct pumping of the quantum wells (QWs), the optimization of the interaction of the QWs with pump and laser field and the reduction of resonator losses by employing a dielectric/semiconductor Bragg reflector on the front face of the disk. GaAs-AlGaAs-quantum-well disk lasers designed accordingly achieved slope efficiencies of 67% and optical efficiencies of 55% (based on the absorbed pump power) with output powers well above 1 W and a pump absorption efficiency of 80%. With an additional simple pump re-imaging an output power of 1.6 W was realized with an optical efficiency of 50% related to the incident pump power.

Bidirectional Optical Interconnection at Gb/s Data Rates With Monolithically Integrated VCSEL-MSM Transceiver Chips

We present the operation characteristics of 850-nm wavelength GaAs-based monolithically integrated transceiver chips designed for low-cost short-distance bidirectional optical data transmission over a butt-coupled 200-mum core diameter polymer-clad silica fiber. The chips containing a vertical-cavity surface-emitting laser and a large-area metal-semiconductor-metal photodiode can well handle data rates of 2.5Gb/s in back-to-back mode and 0.5 Gb/s for 10-m fiber length

Design of Highly Efficient High-Power Optically Pumped Semiconductor Disk Lasers

In this paper, we present a carefully elaborated layer design for semiconductor disk lasers. Experimental results of devices mounted on simple copper heat spreaders reveal a conversion efficiency of 54% at 13.2 W for 970-nm wavelength laser emission and a differential quantum efficiency of 73%.

Monolithic integration of VCSELs and MSM photodiodes for bidirectional multimode fiber communications

The monolithic integration of 850 nm vertical-cavity surface-emitting laser diodes and GaAs-based metal-semiconductor-metal photodiodes is introduced as an approach to bidirectional optical data transmission in the Gbit/s range of data rates. Polymer-clad silica fibers and graded-index fibers with core diameters of 200 and 100 &mgr;m, respectively, serve as the transmission medium, covering link lengths relevant for in-car up to in-house communications and beyond.

Monolithically integrated transceiver chips for bidirectional optical interconnection

We report on the design, fabrication and test results of monolithically integrated transceiver chips consisting of GaAs metal-semiconductor-metal photodiodes and 850nm wavelength vertical-cavity surface-emitting lasers. These chips are well suited for low-cost and compact bidirectional optical interconnection at Gbit/s data rates in mobile systems and industrial or home networks employing large core size multimode fibers.

Complex coupled distributed feedback laser monolithically integrated with electroabsorption modulator and semiconductor optical amplifier at 1.3-micrometer wavelength

We report on the design and experimental results of monolithically integrated optoelectronic devices containing distributed feedback (DFB) laser, electroabsorption modulator (EAM), and semiconductor optical amplifier (SOA). Common InGaAlAs multiple quantum well (MQW) layers are used in all device sections. The incorporation of local lateral metal gratings in the DFB section enables device fabrication by single-step epitaxial growth. The emission wavelength is λ=1.3 micrometer. More than 2 mW single-mode fiber-coupled output power as well as 10 dB/2 V static extinction ratio have been achieved. Modulation experiments clearly show 10 Gbit/s capability.

Frequency-doubled GaAsSb/GaAs semiconductor disk laser emitting at 589 nm

We present the first frequency-doubled yellow emitting GaAsSb/GaAs semiconductor disk laser also referred to as VECSELs. Using a solid-source MBE, a GaAsSb-based semiconductor disk laser has been grown on GaAs. The laser cavity is formed by a Bragg mirror and an external dielectric mirror. Pumping of the GaAsSb quantum wells is done optically by a laser beam. A nonlinear crystal is placed inside the external cavity for frequency doubling. In continuous operation, we achieved a maximum second-harmonic output power of 15 mW at a pump power of 2.1 W. The yellow laser emission at 589 nm was well suitable for sodium absorption spectroscopy. Additionally, we have demonstrated the first semiconductor disk laser emitting in the infrared range 1080-1200 nm.