Optical Head Design for 1 TB Optical Tape drive

A multi-channel Optical Head has been developed to be incorporated with an Optical Tape Drive that enables greater than 1TB capacity and greater than 25 MB/s data transfer rate on a 0.5 mil thick, 0.5 inch wide optical tape that fits in a 3480 style cartridge. The optical design has been optimized to perform at 532 nm with maximum through put in the write path. With use of a 0.6 NA objective lens, sub-micron size marks can be written on a WORM type phase change medium. A single laser, a hologram, and a multichannel modulator increase reliability and manufacturability of this design. Introduction The need for a high capacity and a fast data transfer rate tertiary storage device is continually increasing. With the abundance of inexpensive high capacity magnetic disk drives, the explosive growth of information content on the Internet, and the need to save and keep data electronically for a long period of time, an increasing demand is continuously generated for high capacity tertiary data storage devices. We are developing a high performance Optical Tape Drive at LOTS Technology as a solution to this huge data storage problem. This Optical Tape Drive provides a nominal 25 MB/s data transfer rate and a nominal 1TB capacity in a 3480 style cartridge form factor. Some of the advantages of optical tape drive are as follows. Optical tape provides much higher capacity per removable media unit than any storage device in the market. Very high data transfer rate is readily available for a given tape speed with increasing number of laser beams acting as parallel channels. Media is archival with greater than 30 years life span. The optical tape drive offers non-contact recording and read-back which result in zero head and tape wear. The tape transport mechanics have minimal physical contact with the tape further enhancing tape operational lifetime by reducing tape wear. Last but not the least, the high tape capacity results into fewer media mounts; thus causing less wear in robotics and cartridge. The Optical Tape Drive consists of an optical head, a tape transport, and electronics. A multi-channel Optical Head has been developed to be incorporated with the Optical Tape Drive that supports the underlying required system specifications. I will discuss the intricate system design tradeoffs as they relate to the Optical Head design.