Stable, tunable calibration source for large-beam optical systems

Area of Science:

• Optical Engineering
• Metrology
• Laser Technology

Background:

• Accurate calibration is crucial for free-space optical systems.
• Existing sources may lack the required beam size, stability, or tunability.
• Large beam diameters present unique challenges for optical source design.

Purpose of the Study:

• To present a novel optical calibration source designed for free-space systems with large beams.
• To detail the source's performance characteristics, including power, wavelength tunability, and beam quality.
• To demonstrate its suitability for demanding calibration applications.

Main Methods:

• Development of a high-power, tunable laser system.
• Integration of optical elements to generate a large diameter beam (370 mm).
• Implementation of control systems for power and polarization stability.

Main Results:

• The source produces a 2 W beam tunable from 1545-1570 nm.
• Achieved wavefront error is <λ/15 peak to valley and <0.013λ RMS at 1550 nm.
• Demonstrated power stability of <±0.02 dB and polarization stability of <±1°/h.

Conclusions:

• The developed optical calibration source meets stringent requirements for large free-space beams.
• Its precise control over wavelength, power, and polarization enables high-fidelity optical system calibration.
• This technology advances the capabilities for testing and calibrating complex optical systems.