Broadband Optoelectronic Frequency Response Measurement Using Optical Amplifier with Automatic Level Control

摘要

Optoelectronic frequency response calibration using high extinction ratio (ER) Mach-Zehnder Modulator (MZM) in a heterodyne system is simple and has the potential of traceability to the transfer standard. The response can be calculated from overall optical power of the stimulus signal and the detected RF power. In this paper, the bandwidth of the measurement is enhanced using Optical Amplifier with Automatic Level Control. The amplifier is able to compensate for the optical loss in the MZM which varies with modulating frequencies, thus improving signal to noise ratio of the RF response. The double-sideband suppressed-carrier (DSB-SC) output from the MZM is passed through the amplifier giving constant level output across all frequencies; the optical power only need to be measured once, hence the calibration method is further simplified.