Multi-quantum-well lasers emitting at 1.55 mu m grown by GSMBE

GaInAs/GaInAsP multi-quantum-well structures emitting at 1.55 mu m have been realised by gas source molecular beam epitaxy (GSMBE) over a large range of growth temperature. Threshold current densities as low as 0.81 kA/cm/sup 2/ have been obtained. The first BH lasers fabricated by GSMBE from these heterostructures exhibit low threshold current (18 mA) and linear DC light-current characteristics up to 20 mW.<>     

Reliability studies of gain-guided 0.85 μm GaAs/AlGaAs quantumwell surface emitting lasers

A reliability study of gain-guided 0.85 μm GaAs/AlGaAs quantum well surface emitting lasers is reported for the first time. 32 lasers were randomly selected to operate at 25 or 50 C with bias currents up to 15 mA, about 4 times the threshold values. The power outputs of the 32 lasers showed no noticeable degradation after 2000-3000 hours of operation     

Optimisation of a-factor for quantum dot InAs/GaAs fabry-perot lasers emitting at 1.3 /spl mu/m

Dynamic measurements of the Henry factor alpha_H of InAs/GaAs Fabry-Perot lasers are compared for 3-, 5- and 10-QD layers. While alpha_H dramatically increases with the bias current for 3- and 5-QD stacks, it only amounts to <4 for the 10-layer stack at high currents, a value similar to that of QW-lasers     

Long wavelength GaInAsSb-AlGaAsSb distributed-feedback lasers emitting at 2.84 /spl mu/m

Room-temperature continuous-wave operation of a singlemode GaInAsSb/GaSb/AlGaAsSb distributed feedback (DFB) laser is presented at a record long emission wavelength for this material system of 2.843 /spl mu/m. The threshold current at 20/spl deg/C is 75 mA. Mode selection was realised by metal gratings laterally patterned to a ridge waveguide. By varying the grating period, DFB emission from 2.738 up to 2.843 /spl mu/m is obtained.     

Strained InGaAs quantum well vertical cavity surface emitting lasers emitting at 1.3 /spl mu/m

Results on strained InGaAs quantum well vertical cavity surface emitting lasers for optical interconnection applications are reported. Fundamental mode continuous-wave lasing at wavelengths beyond 1300 nm is demonstrated at room temperature. The metal-organic vapour-phase epitaxy grown structure was processed as top p-type distribute Bragg reflector oxide-confined devices.     

Type-II interband cascade lasers emitting at wavelengths beyond 5.1 /spl mu/m

Type-II interband cascade lasers have been demonstrated at emission wavelengths longer than 5.1 /spl mu/m at temperatures up to 163 K and 240 K in continuous wave and pulsed modes, respectively. The emission wavelengths are the longest attained among III-V interband diode lasers. The threshold current density is as low as 36 A/cm/sup 2/ at 80 K.     

Quantum cascade lasers emitting at lambda greater than 100 /spl mu/m

Quantum-cascade lasers based on a bound-to-continuum transition and emitting at /spl lambda//spl sim/106 /spl mu/m (2.8 THz) are reported. They produce peak output powers of a few milliwatt and can be operated up to a heatsink temperature of 65 K. The devices demonstrate the feasibility of this technology for frequencies below 3 THz.     

Effects of zinc doping in DFB lasers emitting at 1.3 and 1.55 mu m

Reports on the performance of GaInAsP/InP DFB lasers with Zn-doped active region. At both 1.3 and 1.55 mu m the authors achieved a large bandwidth owing to the increased differential gain. The carrier lifetime of the lasers decreased with doping level. The decreased carrier lifetime had the effect of reducing the pattern effect, and they could obtain a clear eye opening with 4 Gbit/s NRZ modulation.<>     

High power operation of GaInAsP/GaInAs MQW ridge lasers emitting at 1.48 mu m

Multi-quantum-well (MQW) ridge lasers have been produced with CW light outputs in excess of 100 mW at 500 mA. The wavelength of operation is 1480 nm and the lasers are suitable for pumping erbium-doped-fibre amplifiers. These are the highest power ridge lasers yet produced in the 1500 nm wavelength region.<>     

GaInAsSb-AlGaAsSb distributed feedback lasers emitting near 2.4 /spl mu/m

We have investigated fabrication and characteristics of continuous wave (cw) GaInAsSb-AlGaAsSb distributed feedback (DFB) lasers in the 2.4-/spl mu/m range. Single-mode DFB emission is obtained without overgrowth by first order Cr-Bragg gratings on both sides of a laser ridge. The cw threshold currents for a cavity with a length of 800 /spl mu/m and a width of 4 /spl mu/m are around 30 mA. At 20/spl deg/C and at an injection current of 190 mA output powers of 8.5 mW were realized. Monomode emission with a side-mode suppression ratio (SMSR) of 33 dB has been obtained.     

Continuous-wave operation of GaInAsSb-GaSb type-II ridge waveguide lasers emitting at 2.8 /spl mu/m

We have realized compressively strained GaInAsSb-GaSb type-II double quantum-well lasers with an emission wavelength of 2.8 /spl mu/m. Using broad area devices, an internal absorption of 9.8 cm/sup -1/ and an internal quantum efficiency of 0.57 is determined. For the increase of the threshold current with temperature, a T/sub 0/ of 44 K is obtained. Narrow ridge waveguide lasers show continuous-wave laser operation at temperatures up to 45 /spl deg/C, with room-temperature (RT) threshold current of 37 mA. At RT, the maximum optical output power per facet of an uncoated 800/spl times/7 /spl mu/m/sup 2/ ridge waveguide laser exceeds 8 mW.     

High-performance 1.3 /spl mu/m InGaAs vertical cavity surface emitting lasers

A report is presented on high-performance InGaAs/GaAs double quantum well vertical cavity surface emitting lasers (VCSELs) with record long emission wavelengths up to 1300 nm. Due to a large gain-cavity detuning these VCSELs show excellent temperature performance with very stable threshold current and output power characteristics. For 1.27 /spl mu/m singlemode devices the threshold current is found to decrease from 2 to 1 mA between 10 and 90/spl deg/C, while the peak output power only drops from 1 to 0.6 mW. Large-area 1300 nm VCSELs show multimode output power close to 3 mW.     

InAsSbP-InAsSb-InAs diode lasers emitting at 3.2 /spl mu/m grown by metal-organic chemical vapor deposition

InAsSb-InAsSbP double heterostructure diode lasers have been grown by metal-organic chemical vapor deposition on (100) InAs substrates. High-output powers of 660 mW in pulse mode and 300 mW in continuous wave operation with 400-/spl mu/m cavity length and 100-/spl mu/m-wide aperture at 78 K have been obtained. These devices showed low threshold current density of 40 A/cm/sup 2/, low internal loss of 3.0 cm/sup -1/, far-field /spl theta//sub /spl perp// of 34/spl deg/ with differential efficiency of 90% at 78 K, and high operating temperatures of 220 K.     

Highly uniform, high quantum efficiency GaInAsSb/AlGaAsSb double heterostructure lasers emitting at 2.2 mu m

GaInAsSb/AlGaAsSb double heterostructure lasers with low pulsed threshold current density were grown previously by liquid-phase epitaxy using a complicated five-layer structure to relieve the strain arising from graded cladding layers. Double heterostructures have now been grown over a narrow temperature range to minimise this grading. These simpler three-layer DH lasers have high room-temperature quantum efficiencies (5.4% per facet) and low broad-area threshold current densities (2.6 kA/cm/sup 2/) which are uniform from chip to chip.<>     

High-T/sub 0/ strain-compensated InGaAsSb-AlGaAsSb quantum-well lasers emitting at 2.43 /spl mu/m

Strain-compensated InGaAsSb-AlGaAsSb quantum-well (QW) lasers emitting near 2.5 /spl mu/m have been grown by solid-source molecular beam epitaxy. The relatively high arsenic composition causing a tensile strain in the Al/sub 0.25/GaAs/sub 0.08/Sb barriers lowers the valence band edge and the hole energy level, leading to an increased hole confinement and improved laser performance. A 60% external differential efficiency in pulsed mode was achieved for 1000-/spl mu/m-long lasers emitting at 2.43 /spl mu/m. A characteristic temperature T/sub 0/ as high as 163 K and a lasing-wavelength temperature dependence of 1.02 nm//spl deg/C were obtained at room temperature. For 2000 /spl times/ 200 /spl mu/m/sup 2/ broad-area three-QW lasers without lateral current confinement, a low pulsed threshold of 275 A/cm/sup 2/ was measured.     

InGaAsSb-AlGaAsSb distributed-feedback lasers emitting at 1.72μm

We have developed distributed-feedback ridge waveguide lasers based on AlGa(In)AsSb emitting at 1.72 μm. The distributed feedback is obtained by first-order Cr-Bragg gratings defined on both sides of the laser ridge. The threshold current under pulsed operation at room temperature was around 180 mA and an output power of 1.5 mW was obtained. The gratings lead to a side-mode suppression ratio of 27 dB     

GaInAsSb-AlGaAsSb tapered lasers emitting at 2 μm

Tapered oscillators fabricated from GaInAsSb-AlGaAsSb quantum-well structure are reported for the first time. The quantum-well laser structure, grown by molecular beam epitaxy, has broad-stripe pulsed threshold current densities as low as 330 A/cm² at room temperature. One tapered laser emitting at 2.02 μm has exhibited continuous wave (CW) output power up to 750 mW, with power in the near-diffraction-limited central lobe as high as 200 mW     

High-performance 1.5 /spl mu/m GaInNAsSb lasers grown on GaAs

Substantially reduced threshold current density and improved efficiency in long-wavelength (>1.4 /spl mu/m) GaAs-based lasers are reported. A 20/spl times/1220 /spl mu/m as-cleaved device showed a room temperature continuous-wave threshold current density of 580 A/cm/sup 2/, external efficiency of 53%, and 200 mW peak output power at 1.5 /spl mu/m. The pulsed threshold current density was 450 A/cm/sup 2/ with 1145 mW peak output power.     

Reliable InGaAs quantum well lasers at 1.1 mu m

Strained-layer InGaAs quantum well lasers operating CW at 1.1 mu m have been life tested to over 18000 h, exhibiting a degradation rate of <.8% per kh. These uncoated lasers were life tested at 70 mW (per facet) in constant-power mode at a heatsink temperature of 30 degrees C. The laser structure, grown by metalorganic chemical vapour deposition, incorporates a step-graded quantum well heterostructure with a 30 AA In/sub 0.45/Ga/sub 0.55/As quantum well.<>     

Long wavelength MOCVD grown InGaAsN-GaAsN quantum well lasers emitting at 1.378-1.41 /spl mu/m

Low threshold InGaAsN QW lasers with lasing wavelength at 1.378 and 1.41 /spl mu/m were demonstrated by metal organic chemical vapour deposition (MOCVD). The threshold current densities are 563 and 1930 A/cm/sup 2/ for the 1.378 and 1.41 /spl mu/m emitting lasers, respectively. The significant improvement of device performance is believed due to utilisation of high temperature annealing and introduction of GaAsN barriers to suppress the resulting wavelength blue shift. A comparable characteristic temperature coefficient of the external differential quantum efficiency, T/sub 1/, is observed for the InGaAsN-GaAsN QW laser compared to similar InGaAsN/GaAs structures.