High-power 980 nm quantum dot broad area lasers

High-power quantum dot broad area lasers emitting at 980 nm are presented. Continuous-wave output powers of 4.3 W from a 50 /spl mu/m stripe width laser and of 6.3 W from a 100 /spl mu/m stripe width laser were achieved at 15/spl deg/C     

Device performance and wavelength tuning behavior of ultra-short quantum-cascade microlasers with deeply etched Bragg-mirrors

The fabrication and characteristics of edge-emitting quantum-cascade (QC) lasers and microlasers with monolithically integrated deeply etched semiconductor-air Bragg-mirrors based on GaAs is reported. We observe a reduction of the threshold current density by 25% and an increase of the operation temperature by 23 K to a maximum of 315 K for 800 /spl mu/m long devices by employing Bragg-mirrors. Devices with ultra-short cavities of about 100 /spl mu/m (/spl sim/40 times the wavelength) operate up to 260 K. At 80 K, these devices show threshold currents as low as 0.63 A and output levels up to 56 mW. In these devices, longitudinal single mode operation with output levels exceeding 7.7, 5.6, and 2.8 mW was measured at 180, 200, and 240 K, respectively. This can be attributed to the limited gain bandwidth of QC lasers and the large mode spacing in these devices. By temperature control the emission wavelength can be tuned without mode jumps over 80 nm. The feasibility to pre-select the emission wavelength by a direct control of the Fabry-Perot mode was demonstrated by microlasers with 1 /spl mu/m cavity length difference.     

High frequency characteristics of InAs/GaInAs quantum dotdistributed feedback lasers emitting at 1.3 μm

The high frequency properties of InAs/GaInAs quantum dot distributed feedback (DFB) lasers emitting at 1.3 μm have been examined. The lasers display a small static linewidth of 1.3 MHz and a chirp as low as 83 MHz/mA. More than 5 GHz small-signal modulation bandwidth was observed in the first devices indicating the potential for high-speed operation of quantum dot lasers     

High-power quantum dot lasers with improved temperature stability of emission wavelength for uncooled pump sources

915 nm quantum dot lasers with temperature stable emission wavelengths have been realised for uncooled high-power applications. Broad area lasers with optimised dot geometry exhibit a thermal induced wavelength shift of 0.09 nm/K, which is 3.5 times lower than for quantum well lasers. Despite this improvement the lasers show high output powers of more than 3 W and wallplug efficiencies of 55% in continuous-wave operation.     

Laterally coupled DBR laser emitting at 1.55 /spl mu/m fabricated by focused ion beam lithography

By using focused ion beam lithography high performance 1.55-/spl mu/m emitting distributed Bragg reflector lasers were realized suitable for high-speed optical telecommunication. Threshold currents of 8 mA and continuous-wave efficiencies of 0.37 W/A for 600-/spl mu/m-long devices were achieved. Stable single-mode emission with sidemode suppression ratios of > 40 dB were observed for the entire operation range. By relative intensity noise measurements an intrinsic 3-dB modulation frequency of > 10 GHz was estimated for a single-mode output power of 23 mW.     

Singlemode InAs/InP quantum dash distributed feedback lasers emitting in 1.9 μm range

Laterally coupled, complex distributed feedback lasers based on InAs/ InGaAs/InAlGaAs/InP quantum dash-in-a-well layers emitting in the 1.9 mum wavelength range were fabricated. Total CW powers above 25 mW at room temperature and sidemode suppression ratios of more than 35 dB are demonstrated, which makes the devices promising for gas sensing applications.     

InAs/GaInAs quantum dot DFB lasers emitting at 1.3 μm

Singlemode operation of 1.3 μm InAs/GaInAs quantum dot lasers has been achieved using the concept of complex coupled distributed feedback. Mode selection was realised by laterally patterned metal gratings. At room temperature the lasers show stable singlemode emission with sidemode suppression ratios of up to 55 dB, threshold currents as low as 17 mA and output powers of up to 8 mW under continuous wave operation     

Transform-limited picosecond optical pulses from a mode-lockedInGaAs/AlGaAs QW laser with integrated passive waveguide cavity and QWmodulator

Using a novel single-top molecular beam epitaxy growth technology on nonplanar substrates, an InGaAs/AlGaAs laser amplifier has been integrated with a 4-mm-long passive waveguide cavity and a QW modulator. Lasing action of the entire structure was achieved by a current of 60 mA flowing through the amplifier section. Mode-locking experiments in which an RF signal was applied to the modulator segment led to nearly-transform-limited pulses with a duration of 4.4 ps and a time-bandwidth product of 0.43     

50 mW CW-operated single-mode surface-emitting AlGaAs lasers with45° total reflection mirrors

The authors report on the fabrication and testing of surface-emitting AlGaAs 3.5 μm ridge lasers with etched mirrors and 45° internal deflectors. The 45° mirror coupling coefficient and the resulting threshold current penalty have been analyzed theoretically and experimentally. A surface-emitted optical power of 50 mW CW at 26 mA threshold current and external differential efficiency of 57% has been achieved in lateral fundamental-mode operation. The optical power density of 14 mW CW per micrometer ridge width is the highest reported to date and produces two-dimensional surface-emitting laser arrays of diffraction-limited beam quality suitable for optical storage applications