Optical feedback interferometry for sensing application

Optics & Laser Technology, 2008

The coherence length of a single mode laser diode (LD) can reach more than 10 m. It allows the application of this source of light to interferometric distance measurement, with a measurement range of several meters. However, the LD's wavelength tunability, which is a result of the dependence of the lasing wavelength on the injection current, prevents the realization of the theoretically possible metrological parameters of the interferometer. In this study, we analyze the influence of a low-frequency signal disturbance, e.g., noise or disturbing modulation inherent to the injection current of the LD, on the repeatability and measurement range of an LD interferometer used for displacement measurements. Both the measurement range and the resolution of the interferometer are found to be highly limited by this factor.

— Laser interferometers have found wide usage in a variety of precision measurement applications. The ability to gain precise position information with minimal change to the dynamics of the device being measured has a large set of advantages. This allows interferometer systems to be used in feedback loops for precision systems. This paper presents a tutorial on laser interferometers, their use in precision motion feedback systems, the issues faced by such systems, and some of the solutions that have been applied to these issues.

Applied Optics, 1987

A method for measuring absolute distance by the wavelength shift of laser diode light has previously been proposed. In this work three serious systematic error sources for the method are discussed and some of the discussion is confirmed by experiment. The error sources are optical feedback effect, longitudinal mode distribution of laser light, and unwanted light reflected from optical devices (coherent noise). The optical feedback effect influences the wavelength shift of the emitted light. The mode distribution causes the periodic error dependent on the measured distance, and the maximum error is determined by the change in the intensity ratio of the submodes to the main mode. Coherent noise causes the periodic error also dependent on the distance, and the maximum error is determined by the amplitude ratio of the measuring lightwave to the noise. These systematic errors are observed in some demonstrative experiments.

Optics Communications, 1995

We describe a diode laser interferometer with an electronic adaptive system of fringe pattern stabilization and vibrations suppression. The interferometer allows to obtain up to four high-quality images with relative phase shifts. Also an algorithm for fringe pattern processing has been proposed.

IEEE Transactions on Instrumentation and Measurement, 2007

We present a new method for the measurement of the absolute distance of a remote target based on the laser diode self-mixing interferometry technique, which is assisted by an electronic feedback loop that is capable of improving the measurement accuracy. The feedback loop supplies a periodic change of the emitted wavelength that exactly corresponds to a single interferometric fringe. This allows the measurement of the target distance with higher accuracy, which, in principle, is limited only by the detection shot noise and not by the fringe quantization error that is typical for the conventional fringe-counting approaches. We developed a prototype that is capable of measuring the target distance with 0.3-mm accuracy in the 0.2-to 3-m range.

Optics Letters, 2019

We demonstrate a nanometric sensor based on feedback interferometry in a DFB laser by using a measurement of either the optical frequency or laser voltage. We find that in an optimal range of optical feedback, the sensor operates reliably down to an extrapolated 12 nm; for the sensor demonstrated here at ∼1550 nm, this provides a minimum detectible displacement of λ/130.

IEEE Photonics Technology Letters, 2013

We propose differential optical feedback interferometry, a technique able to measure nanometer-size amplitude displacements by comparing the optical power of two lasers subject to optical feedback. In this letter, the principles of the technique are explained in detail, and its limits are explored by simulation. Theoretical results are presented showing that the technique can measure nanometer scale displacements with resolution within the angstrom scale. An experimental setup for validation has been built, and a series of experimental tests were performed using a capacitive sensor as a reference. Results show good agreement between theory and experiment with a reasonable reduction in performance due to mechanical coupling and signal noise. The proposed technique, thus, provides measurements of a very high resolution using an extremely simple and robust experimental setup.

AIAA Journal, 1995

A dual beam differential laser interferometer/vibrometer measurement system was developed for studying the steady-state and dynamic behavior of low-weight high-performance mechanical systems. This newly developed optical system employs many optical and mechanical design tactics to achieve design targets such as nanometer displacement accuracy, ease of use, capability of measuring untreated structural surfaces, high-measurement bandwidths, and large-dynamic ranges. Both the optical/mechanical configurations and the design approaches adopted are discussed in detail. A flying slider and thin-film disk system currently used in the disk drive industry were used as the testbed to verify the capabilities of this newly developed nanometer structural displacement/velocity measurement system.

Sixth International Conference on Education and Training in Optics and Photonics, 2000

This paper reviews the theoretical basis of two laser interferometry vibration measuring methods of high accuracy, i.e., frequency ratio and Bessel function minimum point. These techniques are used for low and high vibration frequencies, respectively. The most recent experimental developments are highlighted and contributions to the classic models are shown.

Optics Express, 2011

We demonstrate that a single all-optical sensor based on laser diode self-mixing interferometry can monitor the independent displacement of individual portions of a surface. The experimental evidence was achieved using a metallic sample in a translatory motion while partly ablated by a pspulsed fiber laser. A model based on the Lang-Kobayashi approach gives an excellent explanation of the experimental results.

Applied Optics, 1991

The combined optical spectrum of a pair of multimode laser diodes is composed of a large number of welldefined wavelengths. This work reports the use of three of these wavelengths in a phase-modulated interferometer to measure absolute distance over 360-JLm intervals with a resolution of 0.5 nm. The laboratory demonstration system is composed of a three-wavelength source coupled by single-mode fiber to a compact interferometric probe. This system has been used for displacement measurement and profiling of optical surfaces.

Journal of Optics, 1998

We review the major features of laser diode feedback interferometry for sensing applications. The ensembles of the feedback effects on the optical field can be exploited for several non-contact measurements such as displacement, distance, vibration amplitude and frequency. Methods of signal processing are also discussed.

Laser Interferometry: Quantitative Analysis of Interferograms: Third in a Series, 1990

Laser Diode Technology and Applications II, 1990

Smali amounts of scattered light have strong effects on the behavior of laser diodes.

1996

We discuss the fabrication of a monolithically integrated optical displacement sensors using III-V semiconductor technology. The device is configured as a Michelson interferometer and consists of a distributed Bragg reflector laser, a photodetector and waveguides forming a directional coupler. Using this interferometer, displacements in the 100 nm range could be measured at distances of up to 45 cm. We present fabrication, device results and characterization of the completed interferometer, problems, limitations and future applications will also be discussed.