Abstract

As the bandwidth of optical modulators increases, it becomes more difficult to measure their frequency response. A number of methods are currently in use, including direct detection using a fast, calibrated photodiode [1], the a.m. sideband technique [2], and an optical sampling technique [3]. The first of these is straightforward, but requires a calibrated photodiode with a bandwidth comparable to the modulator under test. The a.m. sideband technique requires non-linear behavior by the modulator. Further, it exhibits a second order dependence of the measured signal on the modulator response and drive voltage, leading to a decreased signal-to-noise ratio. The third technique requires the use of two r.f. sources as well as a source of fast optical pulses (e.g. a mode-locked laser).

© 1988 Optical Society of America