Self-calibrated optical vector analyzer with a largely extended measurement range based on linearly...

Area of Science:

• Optoelectronics
• Metrology
• Optical Engineering

Background:

• Accurate characterization of optical components and systems is crucial for advanced applications.
• Existing optical vector analyzers often face limitations in measurement range and speed.
• Broadband characterization requires efficient methods to sweep across wide frequency spectra.

Purpose of the Study:

• To propose and demonstrate a novel optical vector analyzer (OVA) with an extended measurement range.
• To enhance the frequency range of optical signals using a recircuiting frequency shifter (RFS) loop.
• To achieve high-speed and high-resolution characterization of optical devices and gas samples.

Main Methods:

• Utilizing a linearly frequency-modulated (LFM) waveform within a recircuiting frequency shifter (RFS) loop to extend the signal's frequency range.
• Employing a Mach-Zehnder interferometer (MZI) incorporating the device under test (DUT) and a delay line.
• Implementing a second MZI for system self-calibration and post-digital signal processing for data extraction.

Main Results:

• Demonstrated a significantly increased measurement range of up to 418 GHz.
• Achieved a high frequency resolution of 0.5 MHz.
• Obtained measurement results for a fiber ring resonator and a hydrogen cyanide gas chamber within a short measurement time of 400 µs.

Conclusions:

• The proposed OVA method, leveraging LFM waveforms and an RFS loop, effectively extends the measurement range.
• The system offers a compelling combination of a large measurement range, high speed, and high resolution.
• This technique provides a powerful tool for the characterization of various optical systems and materials.