Abstract

The photonic asynchronous transfer mode (ATM) switch is promising because it may overcome the throughput limitations of electrical systems, and various ATM architectures have been proposed [1 ]-[3J. The optical gates are key components in these photonic ATM systems. These gates should be able to switch between cells within a guard time of a few nanoseconds, and their extinction ratio should be sufficiently large, typically more than 30 dB. The dynamic switching characteristics of an optical gate is usually estimated by directly observing the waveform using an oscilloscope, and the switching speed is determined from the 10%-to-90% rise/fall time. However, it is difficult to estimate the switching speed with a 30-dB extinction ratio by using the conventional method. Here, we propose a new and very simple measurement method for optical gates; this method has a high time resolution of 30 ps and a wide dynamic range of over 30 dB. We measured the dynamic extinction ratio of an electroabsorption (EA) optical gate module using this method, and found that the switching speed of an EA gate remains high even in a saturated condition.

© 1997 Optical Society of America