Monolithically Integrated Michelson Interferometer Using an InGaAs/InAlAs Quantum Cascade Laser at λ = 4 µm

Abstract

In the present article, we propose a monolithically integrated Michelson interferometer using a λ = 4 µm InGaAs/InAlAs quantum cascade laser as the light source. By using simple fringe detection and a four-point interpolation on each fringe, we will be able to detect minimal object displacements of 500 nm—corresponding to 25% of half the laser emission wavelength. Such an interferometric photonic integrated circuit has interesting applications for precision computerized numerical controlled machines. Since the industrial standard of such machines currently consists of glass-based linear encoders with a resolution of 5 µm, our interferometer-based system will enable an improvement of at least one order of magnitude.

Keywords

• InGaAs/InAlAs
• QC laser
• Michelson interferometer
• 500 nm resolution
• precision CNC machines
• position sensor