Storage Area Network (SAN) has gradually developed as the demand for storage capacity and fast access has increased. The traditional way of attaching storage directly to the servers over a SCSI bus has limited scalability. Several drawbacks and limitations have turned up. Switched Fibre Channel SAN resolves all of these issues. In this paper, the architecture of the switch fabric for the SAN is discussed. The complete design of the free-space optical switching core based on the diffractive element and the PLZT shutter is proposed.
Passive optical interconnection is being used in large packet switches to allow size scale up and more efficient heat dissipation from the electronic processors. The line card is the electronic island whose size is determined by thermal dissipation technology. We have selected an optical interconnection technology that is low cost, fiber ribbon, and we are working on the shutter arrays, which allow active routing. This will reduce the demands on the electronic processors. Progress on a 180 Gbps switch will be reported.
Optical switches based on liquid crystal SLM (Spatial Light Modulators) have traditionally been considered unsuitable for packet switching due to slow reconfiguration speed. In this paper we investigate the constraint of reconfiguration time in an optically interconnected packet switch. A system architecture based on the established knockout principle and input/output buffers is simulated with self-similar traffic patterns and packet length statistics obtained from NLANR. Analysis includes packet delay distribution, queue length growth. A physical realisation of the system will use VCSEL arrays, detector arrays and multi-mode ribbon fibre. Data granularity of the system is chosen to match the specification of modern line cards used in routers. It is found that a reconfiguration time in the order of micro seconds is sufficient for an acceptable delay and loss rate. Relationships between required reconfiguration time and system parameters are established.