Use of a multimode short-external-cavity laser diode for absolute-distance interferometry

Area of Science:

• Optics and Photonics
• Laser Physics
• Metrology

Background:

• Fabry-Perot laser-diode cavities are crucial for optical measurements.
• Multiple-color interferometry requires precise wavelength control for absolute distance determination.
• Dispersive gain media influence laser cavity emission spectra.

Purpose of the Study:

• To investigate the resonant-mode structure of a three-wall Fabry-Perot laser-diode cavity.
• To explore the generation of synthetic wavelengths for absolute distance measurement.
• To demonstrate the experimental application of these techniques.

Main Methods:

• Theoretical analysis of the resonant-mode structure.
• Modeling the emission spectrum of a dispersive gain medium (GaAIAs).
• Experimental validation using a short-external-cavity laser diode.

Main Results:

• A single laser diode can generate synthetic wavelengths ranging from sub-200 µm to over a meter.
• The theoretical emission spectrum directly relates to achievable synthetic wavelengths.
• Experimental results confirm the feasibility of the proposed method.

Conclusions:

• The resonant-mode structure of Fabry-Perot laser cavities enables versatile synthetic wavelength generation.
• This approach offers a novel method for absolute distance measurements using a single laser diode.
• The findings have implications for advanced metrology and optical sensing.