Compact switch array provides fast packet routing

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Hassaun Jones-Bey

Researchers at the University of Bristol (Bristol, England) have used a compact indium gallium arsenide phosphide/ indium phosphide (InGaAsP/ InP) vertical coupler optical switch array for high-speed routing of optical data packets.1 The surface dimensions of the 4 × 4 switch array were 1 × 1 mm, and the switching time was less than 1.5 ns. The array was fabricated on an InP substrate, and it used carrier-induced refractive index and gain changes as the switching mechanism. Crosstalk was less than -50 dB, and optical bandwidth was measured in excess of 40 nm.

The researchers mounted the device on an RF submount without temperature control or cooling and modulated the output of a 1554-nm DFB laser with a 10-Gbit/s data stream to provide an input signal. The input signal was passed through a polarization controller and then coupled into the space switch using a lensed fiber (see figure). A pulse generator was synchronized to every other signal packet to send 5-V (80-mA injection current) pulses into the switch array with 10-ns leading and trailing edges. The optical signal was coupled out of the switch using another lensed fiber. The output signal was passed through an optical bandpass filter, detected by a lightwave converter and displayed on an oscilloscope.

Routing of the 10-Gbit/s optical data packets was achieved successfully with a 2-ns interpacket guard-based time, and the researchers expect significant potential for the device in high-speed, all-optical networks because it is bit-rate transparent. For more information, con- tact Richard Penty at


1. S. Yu et al., Electron. Lett. 36(6), 556 (2000).

Researchers at the University of Bristol Center for Communications Research have experimentally achieved optical packet routing at switching times less than 1.5 ns and crosstalk of less than -50 dB using a compact space switch array.

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