High-accuracy optical vector network analyzer for optical notch and bandpass responses.

Area of Science:

• Photonics and Optical Engineering
• Measurement Science and Instrumentation

Background:

• Traditional optical vector network analyzers (OVNA) face limitations in accuracy and measurement range.
• Existing methods struggle with even-order sideband errors and complex postprocessing.

Purpose of the Study:

• To propose and demonstrate a high-accuracy OVNA using carrier-suppressed double sideband (CS-DSB) modulation.
• To overcome limitations of conventional OVNA techniques, including band-pass response measurement and optical filter immunity.

Main Methods:

• Generation of ±1st-order sideband signals via CS-DSB modulation.
• Utilizing the Pound-Drever-Hall (PDH) technique for optical carrier alignment.
• Detection and processing of double the radio frequency (RF) signal for band-stop/band-pass response determination.

Main Results:

• Demonstrated improved measurement accuracy by eliminating even-order sideband errors.
• Achieved single-step measurement, reducing complexity and avoiding postprocessing.
• Successfully measured band-stop responses (6 GHz range, 1.2 MHz resolution) and band-pass responses (0-13 GHz range) of a Fabry-Perot interferometer.
• Exhibited optical filter immunity for accurate near-carrier measurements.

Conclusions:

• The proposed CS-DSB based OVNA offers enhanced accuracy, stability, and simplified operation.
• This technique overcomes limitations of traditional OVNA, enabling precise measurements for diverse photonic applications.
• The method provides a robust and efficient tool for characterizing optical devices.