We present a new hybrid design for GaInNAs-based vertical-cavity surface emitting lasers (VCSELs) at 1285 nm emission wavelength. The VCSELs show record singlemode optical output powers of 1.2 mW from room temperature to 85 degrees C with series resistance of 120 Omega.. The remarkable overall performance is confirmed by a modulation capability at 6 Gbps demonstrated up to 85 degrees C.

We present long-wavelength vertical-cavity surface emitting laser (VCSEL) with a new approach for control of singlemode emission at 1285nm wavelength. The VCSELs show singlemode optical output powers of 1.0mW and a serial resistance between 70Ω and 100Ω.

Exciton photoluminescence (PL) in a GaInNAs/GaNAs quantum well was measured in the temperature range from 15 K to 300 K. Two striking features of the PL were observed: the nonmonotoneous temperature dependence of the Stokes shift and the abrupt increase of the PL linewidth in a rather narrow temperature range. These features are known to be strong indications of the hopping relaxation of excitons via localized states distributed in space and energy. Computer simulations of the hopping relaxation of excitons were carried out. Comparison between the simulation results and the experimental data provides an important and reliable information on the energy shape of the density of states and also on the energy range, in which localized states for excitons are distributed. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In this paper the realization, development and production of 1.3μm vertical cavity surface emitting lasers (VCSEL) with datacom suitable performance are presented. These low cost laser diodes are well suited for optical interconnect applications for LAN and MAN with transmission distances up to 15 km. The possibilities as well as the advantages and limits of shifting the wavelength from commercially available VCSEL emitting at 850nm to 1300nm are discussed. 1300nm VCSELs in a low cost SMD plastic package assembled into an intelligent SFP-module developed by Infineon Technologies are demonstrated.

Fourier transform infrared absorption measurements have been performed on thin films of GaAs1−xNx grown by metalorganic chemical vapour deposition or molecular beam epitaxy on semi-insulating GaAs substrates. The local vibrational mode absorption due to NAs is used to assess the substitutional nitrogen fraction. Based on a comparison with secondary ion mass spectroscopy and x-ray diffraction analysis, the calibration factor for the integrated absorption is derived. Quantitative determination of substitutional nitrogen is possible up to x ≈ 0.05, in epitaxial layers of thicknesses down to 10–100 nm.

In this work we present a study on the determination of N and In content in (Ga(1−x)Inx)(NyAs(1−y)) material system and discuss the incorporation behavior for metal-organic vapor phase epitaxy (MOVPE)-growth. An electrically pumped MOVPE-grown vertical-cavity surface-emitting lasers on GaAs substrate with a (GaIn)(NAs) active region emitting single-mode at 1293nm with record characteristics is presented. The cw output power at room temperature with 1.4mW, a threshold current of 1.25mA and a data transmission rate of 10Gbit/s has been realized.

We have investigated the optical properties of edge-emitting laser structures containing three Ga0.7In0.3N0.005As0.995 quantum wells embedded in GaNxAs1-x barriers grown by metal-organic vapour-phase epitaxy. In a series of three samples the nitrogen content x of the barrier was varied from 0% to 3%. We studied the optical transitions using pressure-dependent photomodulated reflectance (PR) up to 20 kbar at room temperature. Additionally we measured the pressure dependence of the lasing energy and the threshold current of the corresponding laser structures as function of hydrostatic pressure. Due to the large redshift of the Ga(N,As) band gap with increasing N of about 150 meV per percent N, the variation of x leads to a considerable change of the carrier confinement particularly of electrons. The strong increase of the threshold current of the laser device with pressure suggests a swiftly increasing threshold carrier density due to the increasing effective mass and non-parabolicity. Comparing the pressure dependence of the lasing energy and the conduction band edge supports this conclusion.

By measuring the spontaneous emission (SE) from metal organic vapour phase epitaxy (MOVPE) grown ∼1.3 μm GaInNAs/GaAs-based lasers during normal operation, we have quantitatively determined the variation of each of the current paths present in the devices as a function of temperature from 130 to 370 K and compared these with results previously obtained for molecular beam epitaxy (MBE) grown GaInNAs lasers. From the SE measurements we determine how the current, I, close to threshold, varies as a function of carrier density, n, which enables us to separate out the main current paths corresponding to monomolecular (defect-related), radiative or Auger recombination respectively. We find that at room temperature (RT), defect-related recombination contributes ∼360 A/cm2 (MBE) and ∼565 A/cm2 (MOVPE) to the total current density at threshold. Radiative recombination accounts for ∼110 A/cm2 (MBE) and 195 A/cm2 (MOVPE) of Jth with the remaining ∼180 A/cm2 (MBE) and 760 A/cm2 (MOVPE) are due to non-radiative Auger recombination. Our results suggest that a larger threshold carrier density in the MOVPE grown device in comparison to the MBE lasers, can reasonably explain the larger current densities of the different recombination processes at RT. We tentatively associate this with higher optical loss processes in the MOVPE grown material.

Summary form only given. We have succeeded to produce high performance VCSELs emitting at 1300nm with bitrates up to 10 Gbit/s and output-powers above 1 mW with both approaches. Our long-wavelength devices comprise intracavity contacts in order to reduce absorption losses due to doped layers. We present different devices and discuss the impact of design and growth methods.

VCSEL devices for 850nm and 1300nm emission wavelength are presented. suitable for operation in single-channel interconnects as well as parallel optical links. Necessary properties for applications such as 10 Gigabit Ethernet and actual limits for the use of VCSELs are discussed in some detail. Recent progress is demonstrated in developing devices with production-friendly diameters larger than 5mum for 10Gbit/s operation. Also devices with a temperature insensitive monolithically integrated monitordiode are presented and discussed. In order to reach the emission wavelength of 1300nm with a GaAs-based monolithic VCSEL-structure, we use GaInNxAs1-x quantum-wells with a small nitrogen concentration x between one and two percent. We have two different growth approaches, such as solid source MBE with a rf-plasma source to produce reactive nitrogen from nitrogen gas N-2 and MOCVD with unsymmetrical dimethylhydrazine as a precursor for nitrogen. The long-wavelength devices comprise intracavity contacts in order to reduce absorption losses due to doped layers. Bitrates up to 10Gbit/s per channel can be achieved within both wavelength regimes.

We review the status of InGaAsN-based vertical-cavity surface-emitting lasers (VCSELs) emitting in the wavelength range 1.2–1.3 μm and compare them with similar devices that have been realized using other approaches. To prove the potential of InGaAsN-based VCSELs, we present our results for monolithically MBE- and MOVPE-grown and electrically pumped VCSELs on GaAs substrates. Our MBE-grown devices emit at a wavelength of up to 1305 nm with cw output power at room temperature exceeding 1 mW and a threshold current of 2.2 mA. With an oxide-confined current aperture of about 5 μm diameter, they emit up to 700 μW in single-mode operation at room temperature. Bit-error rates of less than 10−11 are achieved for transmission over 20.5 km of standard single-mode fibre at 2.5 Gbit s−1. Our MOVPE-grown VCSELs with a similar device structure emit single mode at a wavelength of 1293 nm with a cw output power of 1.4 mW and a threshold current of 1.25 mA at room temperature. In back-to-back transmission, we reach a data rate of 10 Gbit s−1, proving the feasibility of high-speed data transmission using InGaAsN VCSELs.

In this work we present a detailed study on the determination of N and In content in (Ga(1-x)Inx)(NyAs(1-y)) material system and discuss the incorporation behaviour and the effect of alloy composition on device performance. (GaIn)(NAs)/GaAs heterostructures are grown on GaAs substrates by metalorganic vapour phase epitaxy (MOVPE). All layers are observed to be pseudomorphically strained as derived from comparison of symmetric and asymmetric high resolution x-ray diffractometry HRXRD reflexes. At first a series of about 60 nm thick GaNyAs(1-y) (0< y(N) <0.06) layers are gown. The nitrogen content was measured with SIMS and correlated with the strain results measured by HRXRD. This correlation is found to be consistent with Vegard's law. We have chosen the growth parameters of the GaNAs sample with the highest nitrogen content of y(N) =0.055 and investigated the incorporation of indium. It is observed that for increasing indium content the nitrogen incorporation decreases to y(N)=0.014 for x(In)=0.16. (GaIn)(NAs)/GaAs double quantum well (DQW) structures are grown to study the bandgap variation for indium amounts higher than 0.2. PL results show that only for high indium content superior PL-intensities can be observed. 3QW (GaIn)(NAs) laser structures exhibit threshold current densities of 0.67 kA/cm2 per quantum well at a wavelength of 1305nm.

The authors report an electrically pumped MOVPE-grown VCSEL on GaAs substrate with a GaInNAs active region emitting single mode at 1293 nm with record characteristics. Continuous wave output power at room temperature with 1.4 mW, a threshold current of 1.25 mA and a data transmission rate of 10 Gbit/s has been realised.

By measuring the spontaneous emission from normally operating similar to1.3mum GaInNAs/GaAs-based lasers grown by MBE and by MOVPE we have quantitatively determined the variation of monomolecular (defect-related similar toAn), radiative (similar toBn(2)) and Auger recombination (similar toCn(3)) as a function of temperature from 130K to 370K. We find that A, B and C are remarkably independent of the growth method. Theoretical calculations of the threshold carrier density as a function of temperature were also performed using a 10 band k.p Hamiltonian from which we could determine the temperature variation of A, B and C. At 300K A approximate to 11x10(-8) sec(-1), B approximate to 8x10(-11) cm(3) sec(-1) and C approximate to 6x10(-29) cm(6) sec-1. These are compared with theoretical calculations of the coefficients and good agreement is obtained. Our results suggest that by eliminating defect-related currents and reducing optical losses, the threshold current density of these GaInNAs/GaAs-based edge-emitting devices would be more than halved at room temperature. The results from studies of temperature and pressure variation of similar to1.3mum VCSELs produced by similar MBE growth could also be explained using the same recombination coefficients. They showed a broad gain spectrum and were able to operate over a wide temperature range.