Simultaneous frequency response measurement of electro-absorption modulation transceivers based on a self-referenced pilot operation.

An electro-optic method based on a self-referenced pilot operation is proposed for simultaneously characterizing electro-absorption modulation optoelectronic transceivers with a shared setup. Through inserting and extracting the self-referenced pilot, the frequency responses of electro-absorption modulated lasers (EMLs) and photodetectors (PDs) are independently obtained in a single measurement, and any extra optical-to-electrical or electrical-to-optical calibration is avoided. Specifically, the relative frequency response of the EML at fm is determined through the extracted difference-frequency pilot at fp (close to DC), realizing the low-frequency analysis for an EML. The relative frequency response of PD at 2fm+fp is obtained from the amplitude ratio of the extracted sum- and difference-frequency pilots at 2fm+fp and fp under the microwave driving signal at fm, verifying the doubled measuring frequency range. In the proof-of-concept demonstration, the frequency response of an electro-absorption modulation transceiver is measured up to 40 GHz. Thereinto, the frequency response of the EML is obtained by detecting the fixed low-frequency pilot of 10 kHz, and the frequency response of the PD is extracted with frequency-swept modulation to 20 GHz. The experiment results are compared with those obtained with the electro-optic frequency sweeping method to check for accuracy.