Method and apparatus for synchronizing a mode locked laser with a device under test

摘要

A method and an apparatus for synchronizing a mode locked laser with a device under test. The present invention provides a stroboscopic technique that synchronizes the free running laser pulses of a mode locked laser to a DUT enabling the optical testing of integrated circuits to be performed and waveform measurements to be acquired from a DUT at random operating frequencies. In one embodiment, a laser synchronizing apparatus is configured to be used to test a device under test . The laser synchronizing apparatus includes a mode locked laser generating repeating laser pulses having a first period. A test pattern operating in M clocks when executed on the device under test is constructed. M is an integer and each one of the M clocks has a second period. A time per test pattern is computed such that the time per test pattern provides a sufficient amount of time to execute the constructed test pattern operating in the M clocks. The time per test pattern is a common multiple of the first period and the second period such that N laser pulses are generated during the time per test pattern with N being an integer. The test pattern is looped on the device under test with the laser synchronizing apparatus synchronized with the mode locked laser and each loop of the test pattern taking the time per test pattern to execute.