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.
By measuring the spontaneous emission from normally operating ~1.3um GaInNAs/GaAs-based lasers grown by MBE and by MOVPE we have quantitatively determined the variation of monomolecular (defect-related ~An), radiative (~Bn2) and Auger recombination (~Cn3) 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=11x10-8 sec-1, B=8x10-11 cm3 sec-1 and C= 6x10-29 cm6 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 ~1.3um 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.
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 5µm 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 N2 and MOCVD with unsymmetrical di-methylhydrazine 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.