1.1-µm Band Extended Wide-Bandwidth Wavelength-Swept Laser Based on Polygonal Scanning Wavelength Filter

Area of Science:

• Optoelectronics
• Laser Physics
• Materials Science

Background:

• Wavelength-swept lasers (WSLs) are crucial for various spectroscopic applications.
• Extending the operational bandwidth of WSLs, particularly in the 1.1-µm range, is an active area of research.
• Semiconductor optical amplifiers (SOAs) offer potential for broadband laser design.

Purpose of the Study:

• To demonstrate a novel 1.1-µm band extended wideband wavelength-swept laser (WSL).
• To investigate the performance characteristics of the WSL, including bandwidth and power.
• To showcase an application of the WSL in observing dynamic changes in a cholesteric liquid crystal (CLC) cell.

Main Methods:

• Constructed a wideband WSL combining two SOAs with center wavelengths at 1020 nm and 1140 nm.
• Configured the SOAs in a Mach-Zehnder interferometer arrangement.
• Employed a polygonal scanning wavelength filter for wavelength sweeping.
• Fabricated a CLC cell for application demonstration.

Main Results:

• Achieved a 10-dB spectral bandwidth of approximately 228 nm at a scanning speed of 1.8 kHz.
• Obtained an average output power of 16.88 mW.
• Observed a decrease in bandwidth with increasing scanning speed due to SOA nonlinear effects.
• Demonstrated instantaneous pitch jumps in the CLC cell's reflection band under applied electric fields.

Conclusions:

• The developed WSL effectively operates in the 1.1-µm band with significant bandwidth.
• The laser's performance is influenced by scanning speed and SOA nonlinearities.
• The WSL is a viable tool for observing dynamic optical responses in materials like CLC cells.