Photodiode-free Doppler velocimeter based on self-mixing effect in commercial VCSELs

Perchoux, Julien; Dougan, H.E.; Bony, Francis; Rakić, Aleksandar D.

doi:10.1109/icsens.2008.4716438

Cited by 8 publications

(5 citation statements)

References 14 publications

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“…G is the gain function. Compared with some other LSI system with more straightforward structure [28]- [30], the proposed method employs a pair of AOMs for the heterodyne modulation. This helps to make the sensor achieve a higher accuracy and resolution, in which the DC drift has been greatly decreased.…”

Section: Design and Principlementioning

confidence: 99%

High Sensitivity and Full-circle Optical Rotary Sensor for Non-cooperatively Tracing Wrist Tremor with Nanoradian Resolution

Xu¹,

Dai²,

Wang³

et al. 2021

Preprint

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<div> In this paper, a novel optical rotary sensor based on laser self-mixing interferometry is developed for the full-circle rotation measurement. The proposed sensor is convenient to use for it does not need any contact with the target or a cooperative mirror. A prototype is fabricated and tested. The measured results demonstrate a good performance compared with other optical rotary sensors, in terms of the 0.1 μrad resolution, the 2.33×10-4 linearity and 2 μrad stability over one hour. Additionally, the repeatability error is below 14.66 mrad under 9-group full-circle tests, which exhibits the potential to be instrumentalized reliably. Error analysis and limitation discussion have been also carried out. Although the accuracy needs further improvement compared with the best rotary sensor, this method has its unique advantages of high resolution, non-cooperative target sensing and electromagnetic immunity. Hence, the proposed optical rotary sensor provides a promising alternative in precise rotation measurement, tremor tracing and nano-motion monitoring.</div>In this paper, a novel optical rotary sensor based on laser self-mixing interferometry is developed for the full-circle rotation measurement. The proposed sensor is convenient to use for it does not need any contact with the target or a cooperative mirror. A prototype is fabricated and tested. The measured results demonstrate a good performance compared with other optical rotary sensors, in terms of the 0.1 μrad resolution, the 2.33×10-4 linearity and 2 μrad stability over one hour. Additionally, the repeatability error is below 14.66 mrad under 9-group full-circle tests, which exhibits the potential to be instrumentalized reliably. Error analysis and limitation discussion have been also carried out. Although the accuracy needs further improvement compared with the best rotary sensor, this method has its unique advantages of high resolution, non-cooperative target sensing and electromagnetic immunity. Hence, the proposed optical rotary sensor provides a promising alternative in precise rotation measurement, tremor tracing and nano-motion monitoring.

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Section: Design and Principlementioning

confidence: 99%

High Sensitivity and Full-circle Optical Rotary Sensor for Non-cooperatively Tracing Wrist Tremor with Nanoradian Resolution

Xu¹,

Dai²,

Wang³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…The classical approach to model the self-mixing effect transforms the three mirror cavity into an equivalent FabryPérot structure, a system sensitive to variations of the external cavity length and that originates a frequency shift of the backscattered light [13]. The self-mixing interference occurs inside the laser diode (LD) cavity when, the emitted light is reflected by a moving object and, afterwards, that backscattered light re-enters in the LD cavity.…”

Section: Introductionmentioning

confidence: 99%

New optical probe approach using mixing effect in planar photodiode for biomedical applications

Pereira

Vaz

Oliveira

et al. 2013

Optical Sensors 2013

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The laser diode self-mixing technique is a well-known and powerful interferometric technique that has been used in biomedical applications, namely for the extraction of cardiovascular parameters. However, to construct an optical probe using the self-mixing principle which is able to acquire signals in the human carotid artery, some problems are expected. The laser diode has a small aperture area, which means that, for physiological sensing purposes, it can be considered as a point-like detector. This feature imparts difficulties to quality recording of physiological signals since the number of photons collected and mixed in the cavity of the photodiode is very small. In order to overcome this problem, a new mixing geometry based on an external large area planar photodiode (PD) is used in the probe, enabling a much larger number of photons to be collected, hence improving the quality of the signal. In this work, the possibility to obtain the mixing effect outside the laser cavity using an external photodetector, such as a planar photodiode, is demonstrated. Two test benches were designed, both with of two reflectors. The first one, which reflects the light beam with the same frequency of the original one is fixed, and the second one, is movable, reflecting the Doppler shifted light to the photodetector. The first test bench has a fixed mirror in front of the movable mirror, creating an umbra and penumbra shadow above the movable mirror. To avoid this problem, another test bench was constructed using a wedged beam splitter (WSB) instead of a fixed mirror. This new assembly ensures the separation of a single input beam into multiple copies that undergo successive reflections and refractions. Some light waves are reflected by the planar surface of WSB, while other light beams are transmitted through the WSB, reaching the movable mirror. Also in this case, the movable mirror reflects the light with a Doppler frequency shift, and the PD receives both beams. The two test benches were designed to demonstrate that it is possible to obtain mixing effect outside the laser cavity, using a planar photodiode. The Doppler spectrograms from the signals acquired in the test benches show that the signal frequency changes along time which correspond to the modulus of the derivative of the mirror movement, as expected in the self-mixing signals. Nevertheless, the test bench A showed better results than the test bench B. This fact probably results from the attenuation that the original beam suffers in each reflection and refraction in the WBS. Tests developed in the test benches opened the possibility to construct a probe that uses a planar photodiode with a large area to collect medical signals, and improve the quality of the acquisition with a better SNR. Keyword: mixing effect; self-mixing interference, Doppler effect, biomedical optics, laser diode, planar photodiode, wedged beam splitter.

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“…The basic theory of the self-mixing effect is explained by the presence of two Fabry-Perot cavities whose parameters are sensitive to variations of the external cavity length and frequency shift of the back-scattered light [8][9][10]. The light from the LD is focused on the remote target and undergoes a Doppler frequency shift proportional to the target surface orthogonal velocity.…”

Section: Self-mixingmentioning

confidence: 99%

Submicron Surface Vibration Profiling Using Doppler Self-Mixing Techniques

et al. 2014

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Doppler self-mixing laser probing techniques are often used for vibration measurement with very high accuracy. A novel optoelectronic probe solution is proposed, based on off-the-shelf components, with a direct reflection optical scheme for contactless characterization of the target's movement. This probe was tested with two test bench apparatus that enhance its precision performance, with a linear actuator at low frequency (35 m, 5-60 Hz), and its dynamics, with disc shaped transducers for small amplitude and high frequency (0.6 m, 100-2500 Hz). The results, obtained from well-established signal processing methods for self-mixing Doppler signals, allowed the evaluation of vibration velocity and amplitudes with an average error of less than 10%. The impedance spectrum of piezoelectric (PZ) disc target revealed a maximum of impedance (around 1 kHz) for minimal Doppler shift. A bidimensional scan over the PZ disc surface allowed the categorization of the vibration mode (0, 1) and explained its deflection directions. The feasibility of a laser vibrometer based on self-mixing principles and supported by tailored electronics able to accurately measure submicron displacements was, thus, successfully demonstrated.

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Photodiode-free Doppler velocimeter based on self-mixing effect in commercial VCSELs

Cited by 8 publications

References 14 publications

High Sensitivity and Full-circle Optical Rotary Sensor for Non-cooperatively Tracing Wrist Tremor with Nanoradian Resolution

High Sensitivity and Full-circle Optical Rotary Sensor for Non-cooperatively Tracing Wrist Tremor with Nanoradian Resolution

New optical probe approach using mixing effect in planar photodiode for biomedical applications

Submicron Surface Vibration Profiling Using Doppler Self-Mixing Techniques

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