Rapid Linear Frequency Swept Frequency-Modulated Continuous Wave Laser Source Using Iterative Pre-Distortion Algorithm

Zhang, Yating; Yao, Jianquan

doi:10.3390/rs14143455

Cited by 15 publications

(6 citation statements)

References 27 publications

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“…Ten percent of the light waves enter the nonlinear correction optical path composed of two couplers, and the Mach Zehnder (M-Z) interference beat signal of the optical path is received by the photodetector and processed in the upper computer. This optical path uses an iterative predistortion algorithm to perform nonlinear frequency correction of the laser, stabilizing the frequency of the measured optical path beat signal [24].…”

Section: System Constructionmentioning

confidence: 99%

Frequency-modulated continuous-wave laser interferometry measurement method based on cross-correlation

Zhang,

Yan,

et al. 2024

Meas. Sci. Technol.

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Frequency-modulated continuous-wave (FMCW) laser interferometry technology holds significant potential for applications in the fields of ultraprecision manufacturing and high-precision sensing. This paper proposes a novel approach among current phase demodulation methods is based on cross-correlation to address the challenge of this technology. On the basis of nonlinear correction of a distributed feedback (DFB) laser, the intercepted beat frequency signal was first preprocessed with Z-score signal normalization and a smoothing filter. Subsequently, the interference beat signal was subjected to processing using a correlation method to derive the correlation function. Finally, the phase difference between adjacent beat signals was determined by pinpointing the maximum value of the cross-correlation function, enabling accurate displacement demodulation. Experimental validation was performed by constructing an FMCW laser interferometric displacement measurement system. The results indicated that the standard deviation of the displacement error for the cross-correlation method was 2.41 nm during static measurements. Compared to conventional maximum-point method, the static measurement error of the cross-correlation method has been reduced by 1.43 times. In dynamic measurements in the 500 µm range, The measurement error of the cross-correlation method has been reduced by 6.04 times, avoiding the dynamic measurement positioning problem of conventional feature point demodulation methods and making the measurement results more accurate. This advancement holds substantial practical value in the realm of phase demodulation in laser interferometry.

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Section: System Constructionmentioning

confidence: 99%

Frequency-modulated continuous-wave laser interferometry measurement method based on cross-correlation

Zhang,

Yan,

et al. 2024

Meas. Sci. Technol.

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“…As the most effective electronic reconnaissance equipment today, radar has been widely used in a variety of military equipment. In remote sensing technology, the linear frequency modulation (LFM) signal application is particularly prominent [2,3]. An LFM signal can increase radio frequency (RF) pulse width and average transmit power while maintaining sufficient spectrum width.…”

Section: Introductionmentioning

confidence: 99%

An Attention-Guided Complex-Valued Transformer for Intra-Pulse Retransmission Interference Suppression

Wang,

Li,

Zhou

et al. 2024

Remote Sensing

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With the maturation of digital radio frequency memory (DRFM) technology, various intra-pulse retransmission interference methods have emerged. These flexible and changeable retransmission interference methods pose significant challenges to radar detection tasks, particularly in modern battlefields. This paper proposes an attention-guided complex-valued transformer (AGCT) as a solution. First, the encoder maps the received signal contaminated by interference and noise into a high-dimensional space. Then, the dilated convolution block (DCB) group and attention block (AB) group in the mask estimator extract the delicate multi-scale features and large-scale features of the interference, respectively, to obtain a multidimensional space mask. Finally, the decoder restores interference to the time domain and outputs the estimated target echo using residual learning. Considering the characteristics of intra-pulse interference, we introduced the energy attention block (EAB) at the end of the DCBs and the ABs within our network. This addition ensures a heightened focus on extracting interference features. Furthermore, we implemented a curriculum learning strategy during the network training. This approach gradually acclimates the network to fit different types of retransmission interference, starting from simpler to more complex scenarios. Our extensive experiments, conducted under various conditions, have provided compelling evidence of the AGCT’s superior performance. Compared to the comparative network, the AGCT’s advantages are particularly pronounced under more harsh conditions, demonstrating its robustness and effectiveness.

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“…Currently, the research on the frequency-swept linearization can be roughly divided into two main approaches: the active control [6][7][8] and the passive control [9][10][11][12][13]. The active control approach is represented by the closed-loop correction approach.…”

Section: Introductionmentioning

confidence: 99%

“…Another passive correction approach focuses on producing a pre-distorted modulation current waveform using different iterative methods [10,12]. These approaches are capable of generating high linear frequency-swept light and are independent of specific lasers.…”

Section: Introductionmentioning

confidence: 99%

High-Linear Frequency-Swept Lasers with Data-Driven Control

Zhao,

Xu,

et al. 2023

Photonics

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The frequency-swept laser (FSL) is applied widely in various sensing systems in the scientific and industrial fields, especially in the light detection and ranging (Lidar) area. However, the inherent nonlinearity limits its performance in application systems, especially in the broadband frequency-swept condition. In this work, from the perspective of data-driven control, we adopt the reinforcement learning-based broadband frequency-swept linearization method (RL-FSL) to optimize the control policy and generate the modulation signals. The nonlinearity measurement system and the system simulator are established. Since the powerful learning ability of the reinforcement learning algorithm, the linearization policy is optimized off-line and the generated modulation signals reduce the nonlinearity almost 20 times, compared to the case without control. In the long-term operation, the regular updated modulation signals perform better than the traditional iteration results, demonstrating the efficiency of the proposed data-driven control method in application systems. Therefore, the RL-FSL method has the potential to be the candidate of optical system control.

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Rapid Linear Frequency Swept Frequency-Modulated Continuous Wave Laser Source Using Iterative Pre-Distortion Algorithm

Cited by 15 publications

References 27 publications

Frequency-modulated continuous-wave laser interferometry measurement method based on cross-correlation

Frequency-modulated continuous-wave laser interferometry measurement method based on cross-correlation

An Attention-Guided Complex-Valued Transformer for Intra-Pulse Retransmission Interference Suppression

High-Linear Frequency-Swept Lasers with Data-Driven Control

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