Direct time-response measurement of high-speed optical modulators based on stretched-pulse interferometry

Area of Science:

• Optoelectronics
• Signal Processing
• Applied Physics

Background:

• High-speed electro-optic (EO) modulators are critical components in modern communication systems.
• Accurate characterization of their complex temporal response is essential for optimizing performance.
• Existing methods may be complex or limited in bandwidth.

Purpose of the Study:

• To propose a simple and direct technique for measuring the complex temporal response of high-speed EO modulators.
• To enable accurate characterization of modulation bandwidths in the tens-of-gigahertz range.
• To demonstrate the technique by measuring a 2.5 Gbps intensity EO modulator.

Main Methods:

• The technique employs Fourier-transform interferometry with a chirped pulse (generated via linear dispersion).
• It exploits the time-to-frequency mapping induced by the pulse dispersion process.
• Detection can be performed in either the time or frequency domain.

Main Results:

• The method successfully recovers both amplitude and phase temporal profiles of instantaneous modulation.
• Accurate measurement of the complex temporal response of a 2.5 Gbps intensity EO modulator was achieved.
• The technique demonstrated capability for characterizing modulation bandwidths in the tens-of-gigahertz range.

Conclusions:

• The proposed technique offers a simple and direct approach for characterizing high-speed EO modulators.
• It provides a valuable tool for research and development in high-speed optical communications.
• The method's flexibility in detection domains enhances its applicability.