Synthetic-wavelength interferometry improved with frequency calibration and unambiguity range extension

Weimann, C.; Fratz, Markus; Wölfelschneider, H.; Freude, W.; Höfler, H; Koos, C.

doi:10.1364/ao.54.006334

Cited by 6 publications

(4 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This range could be extended by, e. g., subsequent measurements with different comb line spacings mod,sig f [1,12], by a combination with longerrange time-of-flight measurement schemes [21], or by using special schemes in which the LO comb also propagates to the measurement target [41].…”

Section: Measurement Principle and Data Processingmentioning

confidence: 99%

“…Important requirements are high measurement precision, fast acquisition, and the ability to cope with natural technical surfaces characterized by roughness and strongly varying backscattered power levels. In the context of fast and precise distance metrology, optical frequency combs have emerged as valuable tools, either as light sources for the distance measurement itself [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], or as a means for calibrating lasers, e.g., for synthetic-wavelength interferometry (SWI) [19][20][21] or for frequency-modulated continuous wave (FMCW) laser ranging [22,23]. However, all these demonstrations rely on rather complex and sensitive setups that cannot cope with the stringent requirements that are associated with industrial applications.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fast high-precision distance metrology using a pair of modulator-generated dual-color frequency combs

et al. 2018

View full text Add to dashboard Cite

We demonstrate fast high-precision non-contact distance measurements to technical surfaces using a pair of dual-color electro-optic frequency combs for synthetic-wavelength interferometry (SWI). The dual-color combs are generated from continuous-wave (cw) lasers at 1300 nm and 1550 nm, which are jointly fed to a pair of high-speed dual-drive Mach-Zehnder modulators. The dual-color approach is used for continuous and dead-zone-free compensation of temperature-induced fiber drift. We achieve standard deviations below 2 µm at an acquisition time of 9.1 µs for measurements through 7 m of single-mode fiber. Despite the technical simplicity of our scheme, our concept can well compete with other comb-based distance metrology approaches, and it can maintain its accuracy even under industrial operating conditions. The viability of the concept is demonstrated by attaching the fiber-coupled sensor head to an industrial coordinate measuring machine for acquisition of surface profiles of various technical samples. Exploiting real-time signal processing along with continuous fiber drift compensation, we demonstrate the acquisition of point clouds of up to 5 million data points during continuous movement of the sensor head. The paper is structured as follows: Section 2 provides details on the experimental setup and the comb-based distance measurement principle. Section 3 is dedicated to an in-depth characterization of the system performance and to a comparison with competing concepts. In Vol. 26, No. 26 | 24 Dec 2018 | OPTICS EXPRESS 34306 Section 4, we give a detailed description of our experimental demonstrations. The appendices A-F give mathematical details of the multi-heterodyne detection scheme and of the impact of noise on the measurement accuracy. Experimental setup and measurement principle Experimental setup of measurement systemA schematic of the measurement system is depicted in Fig. 1. The optical setup is entirely based on fiber-coupled, commercially available telecom-grade equipment. The light from two cw lasers with wavelengths of cal 1300nm   and obj 1550 nm   and power levels of 15 dBm and 18 dBm respectively is split and combined by fiber couplers, feeding two Mach-Zehnder modulators (MZM1 and MZM2) for frequency comb generation. The light entering MZM2 is additionally frequency-shifted by a pair of acousto-optical modulators (AOM). The carrier at wavelength cal  is shifted by 80 MHz, the carrier at obj  by 55 MHz. The lithium-niobate MZM are driven by sinusoidal electrical signals with frequencies of 39.957 GHz for MZM1 and 40.000 GHz for MZM2. Both signal generators are referenced to a common clock signal (not depicted). The phase-modulated light shows broadband frequency comb spectra with line spacings that are precisely defined by the respective driving frequencies. By adjusting the bias voltage, the relative phase and the amplitudes of the driving signals between both arms of the modulator, spectrally flat frequency combs can be obtained [28,29].The measured spectra are depicted in Fig. 1, Inset...

show abstract

Section: Measurement Principle and Data Processingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fast high-precision distance metrology using a pair of modulator-generated dual-color frequency combs

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Using digital signal processing, phase differences ∆φ between neighboring lines of FC1 are extracted from the individual RF beat tones in the photocurrent, Fig. 1(d), and the distance is evalu-ated by a linear fit according to the relation L =∆φ•c/(4π•FSRFC1), see [2] for details. We use the fit error to quantify the quality of a distance measurement, which allows for automatic removal of bad data points.…”

Section: Dual-comb Distance Measurement Setup and High-precision Meas...mentioning

confidence: 99%

“…Fast and precise optical distance measurement (ODM) techniques are key for many industrial and scientific applications [1]. Among the various techniques, concepts based on frequency combs (FC) and synthetic wavelength interferometry (SWI) are particularly attractive: The precisely defined spacing of comb lines leads to high measurement accuracy independently of the absolute optical wavelength, and the large dynamic range of multi-heterodyne detection ensures robustness with respect to varying sample reflectivity [2][3][4]. The performance of such systems strongly depends on the underlying frequency comb.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast Dual-Comb Distance Metrology Using Dissipative Kerr Solitons

Ganin

Trocha

Pfeiffer

et al. 2017

Conference on Lasers and Electro-Optics

View full text Add to dashboard Cite

Fig. 1: Experimental setup. (a) Soliton Kerr comb generation in high-Q microresonators. Our experiment relies on single-soliton comb states which consist of only one ultra-short pulse circulating around the cavity. This leads to a broadband comb spectrum with a smooth envelope (b) Distance measurement setup. (c) Optical spectrum of FC after amplification. (d) Radio-frequency (RF) spectrum of the photocurrent signal.

show abstract