Construction and performance of a 576×576 single-stage OXC

With the explosive growth in data communications, management of fiber networks becomes a crucial issue. Optical Cross-Connects (OXCs) are ideal for this application, if they satisfy several critical requirements: large fiber count, transparency (to allow future increase of bit rates), and low-loss performance. One practical way to create such an OXC uses a single-stage, free-space design. In this design, an optical unit attached to each fiber creates an expanded beam, which is directed in space. A large number of such optical units can interconnect to form a large, transparent, low-loss OXC. This basic free-space architecture is used in an existing commercial 72×72 multi-mode fiber cross-connect. Excellent performance has been demonstrated by these systems in the field. In this design, beam manipulation is performed with piezoelectric actuators which move the fiber in two degrees of freedom. In the new OXC under development, MEMS mirrors are used to direct the beams rather than the earlier piezo devices. Four control LEDs surround each mirror, emitting short-wave infrared light at 880 nm. These control signals are used for servo control of the position of the MEMS mirrors