Characterization of a FBG sensor interrogation system based on a mode-locked laser scheme

Madrigal, Javier; Fraile-Peláez, F.J.; Zheng, Di; Barrera, David

doi:10.1364/oe.25.024650

Cited by 13 publications

(7 citation statements)

References 8 publications

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“…The modulation depth of the refractive index and the grating period are constant, and the wave vector direction of the grating is consistent with the axial direction of the fiber [3,4]. This kind of gratings has an important application value in fiber lasers, fiber sensors, a dense wavelength division multiplexing (DWDM) system, and a high-speed fiber sensing demodulation system [5][6][7][8][9]. There are many side lobes on both sides of the reflection spectrum of a uniform FBG with high reflectivity, which is caused by Fabry-Perot cavity resonance formed by an abrupt change of the refractive index at both ends of the grating.…”

Section: Introductionmentioning

confidence: 86%

Femtosecond Laser Fabricated Apodized Fiber Bragg Gratings Based on Energy Regulation

et al. 2021

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In this paper, an energy regulation method based on the combination of a half-wave plate (HWP) and a polarization beam splitter (PBS) is proposed for the fabrication of apodized fiber gratings, which can effectively improve the side lobe suppression ratio of high-reflectivity fiber Bragg gratings (FBGs) fabricated by femtosecond laser. The apodized FBGs prepared by this method has good repeatability and flexibility. By inputting different types of apodization functions through the program, the rotation speed of the stepping motor can be adjusted synchronously, and then the position of the HWP can be accurately controlled so that the laser energy can be distributed as an apodization function along the axial direction of the fiber. By using the energy apodization method, the gratings with a reflectivity of 75% and a side lobe suppression ratio of 25 and 32 dB are fabricated in the fiber with a core diameter of 9 and 4.4 μm, respectively. The temperature and strain sensitivities of the energy-apodized fiber gratings with a core diameter of 4.4 μm are 10.36 pm/°C and 0.9 pm/με, respectively. The high-reflectivity gratings fabricated by this energy apodization method are expected to be used in high-power narrow-linewidth lasers and wavelength division multiplexing (WDM) systems.

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Section: Introductionmentioning

confidence: 86%

Femtosecond Laser Fabricated Apodized Fiber Bragg Gratings Based on Energy Regulation

et al. 2021

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“…In order to avoid edge effects and to maximise temperature uniformity in the immersed fibre, the pulse duration was limited to 900 ps (i.e., the laser feedback came from a central 9.0 cm long fibre section). An optical spectrum analyser was used to monitor the frequency (wavelength) shift, similar to monitoring the spectrum of simple intra-cavity FBG systems [40,41]. Fig.…”

Section: Applicationmentioning

confidence: 99%

A mode-locked random laser generating transform-limited optical pulses

Weid

Correia

Tovar

et al. 2023

Preprint

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Ever since the mid-1960’s, locking the phases of modes enabled the generation of laser pulses of duration limited only by the uncertainty principle, opening the field of ultrafast science. In contrast to conventional lasers, random lasers usually lack at least a mirror and generally emit broadband low-coherence light. They have, nevertheless, cavity modes that distinguish them from amplifiers and superluminescent light sources. Mode spacing in random lasers is ill-defined because optical feedback comes from scattering centres at random positions. Although progress has been made towards locking spatial and longitudinal modes in random lasers, the literature lacks reports on transform-limited pulse generation despite the many decades of the field. Here the generation of sub-nanosecond transform-limited pulses from a mode-locked random fibre laser is described. Exceedingly weak (<-73 dB) Rayleigh backscattering from decimetre-long sections of telecom fibre serves as laser feedback, providing narrow spectral selectivity to the Fourier limit. This unique laser is adjustable in pulse duration (0.34-20 ns), repetition rate (0.714-1.05 MHz) and can be temperature tuned. The high spectral-efficiency pulses are applied in distributed temperature sensing with 9.0 cm and 3.3x10-3 K resolution, exemplifying how the results can drive advances in the fields of spectroscopy, telecommunications, and sensing.

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“…The SOA-based FRL operates as a switchable pulsed modelocked laser [35], which works fundamentally differently than traditional continuous wave (CW) or mode-locked lasers. The cavity dynamics are much more complicated than either CW or mode-locked lasers because of the multiple physical effects involved.…”

Section: Introductionmentioning

confidence: 99%

Dual pulse heterodyne distributed acoustic sensor system employing SOA-based fiber ring laser

2023

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Distributed Acoustic Sensor (DAS) has potential in applications such as hydroacoustic detection. In this paper, a dual-pulse heterodyne distributed acoustic sensor (DAS) system using a semiconductor optical amplifier (SOA)-based fiber ring laser (FRL) is proposed. Unlike the previous DAS system configurations, the SOA-based FRL replaces the narrow linewidth laser (NLL) and pulse modulator, reducing costs and simplifying the system. The system is demonstrated theoretically and validated experimentally. The adaptability of the SOA-based FRL in the heterodyne DAS system has been demonstrated in the experiments. Using the dual-pulse heterodyne detection method, the sensor system responds well to distributed acoustic detection and achieves accurate demodulation and positioning. A high signal-to-noise ratio (SNR) of 42.51 dB at 3 kHz is demonstrated as a demodulation result. The system’s frequency range is 5 Hz to 5 kHz with a spatial resolution of 12 m. The proposed approach shows a broad application prospect for low-cost, large-scale, high-SNR distributed acoustic detection in maritime surveillance.

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Characterization of a FBG sensor interrogation system based on a mode-locked laser scheme

Cited by 13 publications

References 8 publications

Femtosecond Laser Fabricated Apodized Fiber Bragg Gratings Based on Energy Regulation

Femtosecond Laser Fabricated Apodized Fiber Bragg Gratings Based on Energy Regulation

A mode-locked random laser generating transform-limited optical pulses

Dual pulse heterodyne distributed acoustic sensor system employing SOA-based fiber ring laser

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