Self-calibrating measurement of high-speed electro-optic phase modulators based on two-tone modulation

Area of Science:

• Photonics and Optical Engineering
• Electrical Engineering and Applied Physics

Background:

• Accurate characterization of electro-optic phase modulators is crucial for high-frequency optical systems.
• Traditional methods for measuring modulator frequency response often require complex calibration procedures and are susceptible to photodetection fluctuations.

Purpose of the Study:

• To introduce a novel self-calibrating method for high-frequency response measurement of electro-optic phase modulators.
• To eliminate the need for manual correction of responsivity fluctuations in photodetection during measurements.

Main Methods:

• The proposed method employs two-tone modulation of the optical signal.
• It utilizes electrical domain measurement of the heterodyning spectrum between the modulated optical signal and a frequency-shifted optical carrier.
• High-resolution electrical spectrum analysis is used for precise measurements.

Main Results:

• Experimental demonstration successfully measured high-frequency modulation depth and half-wave voltages.
• Results were compared favorably against the traditional optical spectrum analysis method.
• The self-calibrating approach demonstrated its capability for accurate frequency response determination.

Conclusions:

• The developed method offers a calibration-free and accurate approach for characterizing electro-optic phase modulators.
• This technique simplifies the measurement process by leveraging electrical domain analysis.
• It provides a robust solution for high-frequency response assessment in photonic devices.