Optoelectronic directional couplers for optical switching fabrics

Optical switching fabrics (optical cross-connects) require arrays of highly interconnected optical switching devices. Such fabrics require a high density of optical and electronic interconnect.  The optical switching devices are also required to switch configurations in sub-ns time intervals to enable reconfiguration times between packets that introduce little if any latency. Currently such fabrics do not exist commercially (8x8 demonstrated) and all routing is done with circuit switched architectures.  Possible candidates include MEMS mirror arrays, electro-optic switches, interferometric switches, digital optical switches, liquid crystal switches, bubble switches, acoustooptic switches  and semiconductor amplifier switches. The issues are insertion loss, crosstalk, extinction ratio, polarization dependence and scalability. The only approach with high speed potential is the electro-optic switch. The only electro-optic switch with small size and scalability is the semiconductor based directional coupler. The only semiconductor directional coupler that can be scaled to lengths <500um and that may be integrated with other optical and electronic circuits is fabricated in POET a new platform technology for OE integrated circuits. In this SBIR, ODIS will develop the directional coupler as the key switching device within the fabric and demonstrate the potential for sub-ns switching, low insertion loss, high density and connectivity to a router processor. BENEFIT: marketed by the major server suppliers and telecommunication networking companies such as Ciena, Juniper, Cisco, Netgear etc. The optoelectronic chip developed here will outperform and other challenging technology by an order of magnitude. Therefore market penetration is assured. This technology platform will also address the other issues in optical routers such as wavelength conversion, optical DRAM, high speed logic within the router processor etc. One can therefore expect a proliferation of communications products based on optoelectronic designs.