Chunfeng Ge's research while affiliated with Tianjin University and other places

... This approach leveraged deep learning to overcome the limitations of traditional recognition algorithms in deep feature extraction. Similarly, Lyu et al. [13] developed a lightweight attention residual network (DLA-ResNet) and its application in marine environment monitoring, achieving a recognition accuracy of up to 96.50% by training signals in the form of two-dimensional images. Although the two-dimensional image transformation method is effective, it may introduce additional noise and information loss due to preprocessing. ...

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Research on broken wire identification method based on PoolConv for prestressed concrete cylinder pipe

... By modulating carrier density inside the laser cavity, the frequency can be directly tuned, typically exhibiting a strong correlation with the output intensity [14], which is known as linewidth enhancement effect. Based on such method, a DFB laser under pulse current driving can serve as a high-performance wavelength sweeping light source in the 4-D FMCW LiDAR system with a high velocity sensitivity [15,16]. Besides, linearization processes are usually employed to compensate for the nonlinearity during such wavelength sweeping process through the pre-distortion of laser driving waveform [8,17]. ...

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Linearization of wavelength sweeping lasers for the construction of 4-D FMCW LiDAR images of slow-moving objects using baseband beat note signals

... The OLT's price tag is critical in determining the final bill. It is possible to generate a wide range of frequencies from a single laser source using an optical multicarrier (OMC) generator [17][18][19]. The cascaded arrangement of a different or a single modulator is one of several recent ways of generating OMCs [20-23]. ...

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A High-Capacity Optical Metro Access Network: Efficiently Recovering Fiber Failures with Robust Switching and Centralized Optical Line Terminal

... Wavelet transform (WT) stands as a widely employed technique for denoising, filtering, and compressing signals in distributed fiber optic sensing systems, contributing to the enhancement of various sensing technologies, such as Brillouin optical time-domain analyzer (BOTDA), Brillouin optical time-domain reflectometry (BOTDR), Raman optical time-domain reflectometry (ROTDR), phase-sensitive optical time-domain reflection (φ-OTDR), and optical frequency-domain reflectometer (OFDR), among others technologies [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Its synergy with artificial intelligence methods also helps in time-frequency feature analysis and facilitates feature extraction [15][16][17][18][19][20][21][22]. ...

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Wavelet Decomposition Layer Selection for the φ-OTDR Signal

... In the past decade, numerous optical tactile sensors based on optical fiber have been reported. Fiber Bragg grating (FBG) has been widely used in the field of tactile sensing due to its favorable linearity and uncomplicated structure [8][9][10]. In 2023, Guan et al. introduced a tactile force sensor employing a square hole structure based on FBG for detecting touch in robotic fingers, with a detection sensitivity of 8.85 pm/N and a detection limit of 0.2 N [10]. ...

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Ultrasensitive measurement of tactile force based on a PDMS-embedded microfiber Mach-Zehnder interferometer

... The research indicates that the FBG will also occur axial deformation under axial stress, which increases the periodicity of the grating, and reduces the radius of the core and the shell of the fiber. The wavelength change of fiber grating under axial strain can be expressed as [36]: ...

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Immune to temperature interference sensor of carbon dioxide gas concentration based on a single modified fiber Bragg grating

... Nyquist OTDM (N-OTDM) attracts the attention of researchers with a Nyquist pulse featuring a sinusoidal time-domain waveform and rectangular spectrum. Based on this characteristic, N-OTDM is propitious to reduce the required bandwidth and improve spectrum efficiency in information transmission; thus it has potential to achieve an ultrahigh data transmission rate [1][2][3]. In addition, the newly developed Nyquist WDM (N-WDM) technique can realize comparable spectral efficiency as optical orthogonal frequency division multiplexing (O-OFDM), while the complexity of the receiver is reduced and the nonlinearities of the link are insensitive. ...

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Photonic generation of frequency-doubling Nyquist pulses using external modulation

... The structures of a multicarrier light source mainly include cascaded modulators [5][6][7], the cascade of modulators and highly nonlinear fibers (HNLFs) [8,9] and a recirculating frequency shift loop (RFSL) [10][11][12]. The common feature of these schemes is the utilization of an electro-optic modulator (EOM) driven by a radio frequency (RF) signal to modulate the optical carrier to generate multiple subcarriers. ...

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Ultra-flat multicarrier light source based on recirculating frequency shift loop driven by a parity–time symmetric optoelectronic oscillator

... Guo and Zhu [10] combined machine-vision technology and algorithm to directly identify and track the obvious features of large structures using a telephoto lens, which could realize longdistance vibration measurement of large structures. The projection fringe method is also a common vibration measurement method based on machine-vision [11][12][13]. This method is particularly suitable for structures whose surface features are not apparent. ...

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Modal analysis of beam-like structures using multipoint dynamic testing vision system based on composite fringe pattern

... (Corresponding author: Wei Fan) study the latter one whose fundamental principle is bandstitching. This principle has also been widely used in other applications when bandwidth extension is considered, such as channel sounding [11], channel emulation [12]- [14], and signal generation [15]. ...

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On Band Stitching for Wideband Vector Measurements With Vector Signal Analyzers