Optical beam direction compensating system for board-to-board free space optical interconnection in high-capacity ATM switch

In interconnections between bookshelf-assembled asynchronous transfer mode (ATM) switch boards, a large number of micro-optical signal beams can be optically interconnected by a beam direction compensating system using a vertical cavity surface emitting laser, an x-y beam positioning sensor and a beam deflector made of an adjustable liquid prism, This beam direction compensating system can suppress the decrease in coupling efficiency between transmitters and receivers to no more than 15%, even if boards are inserted and extracted repeatedly, and are shocked repeatedly at a high intensity of 100 G. The compensation is very fast (20 ms), Furthermore, various optical interconnections necessary for ATM switching networks can be achieved by beam deflectors of a liquid crystal microprism array, In this preliminary study, we fabricate no more than eight-channel optical interconnections, However, since one surface emitting laser diode can have many channels in a small area (64 channels per 4 mm, and the aperture of this adjustable liquid prism is wide (28 mm in diameter) and uniform, a huge number of optical interconnection channels will be is possible using this system.