The VISIT Project focuses on strategic, high-value photonic components and subsystems for economic broadband access and local area networks.

The central objective is the research, development, test and exploitation of system-enabling optical transmitters with superior performance. This will be achieved by completely new laser designs, overcoming the limitations of present devices.

A key innovation is the use of a vertically integrated electro-optical modulator (EOM) in a vertical cavity surface emitting laser (VCSEL) as well as in an edge emitter. The electro-optic modulation changes the light output using electric field effects, while in a conventional laser the current is modulated. The EOM concept should therefore allow datarates beyond 40 Gbit/s without a loss of reliability and with similiar cost. With this concept VCSEL with the novel integrated electro-optically modulated bragg reflector, the EOM BR VCSEL, and the edge emitting tilted wave lasers with the integrated electro-optical modulator, the EOM TWL, will be realized.

In addition, to allow bench-marking of the EOM concept, advanced current modulated VCSELs for datarates up to 40 Gbit/s will also be developed. These novle direc­tly-modulated VCSELs target applications at 16-40 Gb/s (e.g. for the Fibre Chan­nel, InfiniBand standards) and bridge the inter­mediate bandwidth demand in the nearer future.

The VCSELs will cover the 850 nm wavelengths range used in very short links over multimode fiber (e.g. Storage Area Networks / SAN and Local Area Networks / LAN) and the wavelengths range around 980 nm which can be used in chip-to-chip interconnects and in active optical cable applications. The EOM-TWL targets the 1.3 µm range used in larger networks (LAN and access networks). While 850 nm and 1300 nm are already established standards, 980 nm may play an important role in very short links.

Epitaxial growth of these structures, processing and design of high-frequency modules are challenging tasks that demand detailed modelling. Low power driver circuitry, as well as system integration and performance requirements will also be dealt with.

The project further aims at creating economic impact. Therefore, it will establish an industrial supply chain from production of epitaxial wafers up to manufacturing and testing of prototype systems, and contribute to international standardization and roadmapping.