Optical interconnects using vcsels based on as/n compounds

Project Information

OPTIVAN

Grant agreement ID: BRPR980721

Start date 1 July 1998

End date 30 September 2001

Funded under

• Specific research and technological development programme in the field of industrial and materials technologies, 1994-1998

Total cost € 0,00

EU contribution No data

Coordinated by

INFINEON TECHNOLOGIES AG
Germany

Deliverables

Development of GaInNAs based 1.3µm VCSEL chips for data-communication applications

Monolithic GaInNAs VCSELs for 1.3µm emissions have been developed and characterised. Material growth conditions and physical properties of the novel GaInNAs/GaAs material system have been investigated by MOVPE and MBE technology. Due to complex gas phase reactions the controllability of the MOVPE process is much more complex than the GaInNAs growth by MBE. According to problems with optical losses in the Bragg mirror structure part, an intracavity contacted VCSEL configuration with undoped AlGaAs/GaAs layers has been realised. The MBE grown VCSELs emit at wavelengths up to 1306nm and exhibit output-powers of more than 1mW at room-temperature and cw-operation up to 80°C. Single mode emission with a side mode suppression ratio of more than 35dB is achieved up to a driving current of 7mA. Data transmission at a rate of 10Gbit/s has also been demonstrated. These 1.3µm GaInNAs VCSEL chips are going to be further developed to a commercial product including the development of a full datacom transmitter module.

Improved precursors for dilute nitride MOVPE

A range of nitrogen precursors for the deposition of dilute N containing semiconductor alloys were investigated. The highest potential sources were purified using techniques developed on the project. Monitoring of their quality was performed using analytical techniques also developed on the project to ensure the highest specification products were isolated. Production processes for these new precursors have now been developed to allow their supply on a commercial basis to allow the fabrication of state of the art devices using MOVPE. A high purity EpiPure grade of Dimethylhydrazine has proved most popular.

Development of GaInNAs QW laser structures by MOVPE with emission at 1.3µm

IQE has been developing an MOVPE-based epitaxial growth technology for the realisation of InGaAsN layers with emission around 1.3 mm suitable for incorporation into edge-emitting and vertical cavity (VCSEL) laser structures. The technology is based on the use of dimethylhydrazine as the nitrogen precursor and edge-emitting laser structures have been successfully demonstrated with emission at 1.3 mm wavelength and threshold current density around 1200 A/cm-2. This result is equivalent to the state-of-the-art for MOVPE material. Similar structures at 1.25 mm gave a threshold current density around 400 A/cm-2. However 1.3 mm VCSEL structures were not successfully achieved. This result is in agreement with published work confirming the difficulty of this task using MOVPE.Further work is required to commercialise the MOVPE technology for 1.3 mm VCSELs and may not be possible without some significant scientific breakthrough. Nevertheless the customers for such a product are numerous since it is expected that the 1.3 mm VCSEL will replace the 850 nm VCSEL in future data communications applications.

Development of strain-balanced MQW epitaxial structures by MOVPE

IQE have established optimised MOVPE growth conditions for strain-balanced InGaAs/GaAsP MQW structures. Such structures are capable of strong luminescence at wavelengths as long as 1.2 mm with narrow linewidths (FWHM < 45 meV) and are compatible with the production of long wavelength lasers in the range 1.0 to 1.2 mm. Previously the maximum wavelength for InGaAs based QW’s was limited to around 1.0 mm. These layers can be used in many applications requiring emission or absorption in this wavelength range such as 1.0-1.2 mm lasers or Saturable Bragg Reflectors for high power mode-locked 1.064 mm lasers. The Institute of Photonics have developed the technology for SBR’s and demonstrated working parts using IQE material.The basic growth principles established for the InGaAs/GaAsP strain-balanced structure can also be applied to other materials systems. Currently IQE is involved in ‘THE REV’ EC project (ERK6-CT-1999-00019) where we are developing strain balanced InGaAs/InGaAs (tensile/compressive) layers on InP for Thermo Photo Voltaic (TPV) cell applications.