Design and Fabrication of Multimode Optical Switches.
Final technical rept. 5 Jun 80-5 Sep 81,
SPERRY RESEARCH CENTER SUDBURY MA
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A new optical switching component for multimode fiber-optic networks has been developed. This voltage-controlled switch is an 8-port device coupled by GRINrod lenses to four input fibers and to four output fibers graded index, 50 micron core diameter. The device switches light from any input fiber to any output fiber in a simultaneous 4-fold inputoutput pairing, and there are 24 such states in this nonblocking matrix switch. Switching is accomplished via controlled reflection from two 6 micron layers of nematic liquid crystal. This switch is the first multimode, electro-optic, fiber-optic matrix. Construction is simple and compact only four glass prisms and two liquid layers are used in the switch. The matrix architecture is based on a new dual-switching-array concept, a two stage interconnection that provides very low levels of optical crosstalk more than 53 dB below the optical input level. The 5-ms onoff response time is faster than that of electro-mechanical matrices, although the 40 Vrms addressing voltage is higher. The optical insertion loss had a minimum value of 6dB and an average value of 15 dB. The latter is due to misalignment of fibers during attachment to the switch, which can be remedied. Because the present switch does not use moving parts, it is quite reliable. Author
- Fiber Optics and Integrated Optics