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In this study, we demonstrate In-line fiber Mach-Zenhder interferometer measuring for vibration in this device we using the hydrogen flame, this sample device can excited high order cladding mode then we used such interferometer to measure vibration.
We review our contribution in the half-wave plate based technique to eliminate birefringence in PLC-based direct D(Q)PSK receiver and arrayed waveguide grating (AWG). In a direct DPSK receiver, a half-wave plate and heating electrodes are added on the arm waveguides of the DLI, to eliminate the PDFS of the delay-line interferometer (DLI). By applying a proper heating current, a residual PDFS of practically...
We developed a new technique for constructing humidity sensor comprised of two cascaded peanut-shape structure which were coated with polyvinyl alcohol (PVA) and in between was also coated with PVA. The coating changes with the humidity which resulting in the change of the effective refractive index, and lead to the change of the interference wavelength. Experiments show that, with the humidity changes...
A distributed sensing network using a chirped ultra-weak fiber Bragg grating array is proposed and experimentally demonstrated. This network is based on time-division multiplexing (TDM) technique. We use a path-match interferometry to obtain interference signal, then amplitude, phase, frequency and location information can be demodulated from interference signal by employing the passive 3 × 3 coupler...
Recently, Φ-OTDR based on optical I/Q demodulation has been proposed as a promising solution for distributed acoustic sensing. This paper characterizes the imbalance of coherent-receiver optical front-end, and analyses its impact on phase demodulation in Φ-OTDR with coherent detection.
We demonstrate a silicon PAM-4 optical modulator, which is based on a symmetric Mach-Zehnder interferometer. Two uncorrelated binary electrical signals with different peak-to-peak voltages are applied to the phase shifters of the silicon optical modulator. Accordingly, two different phase shifts are generated in the two arms. After the permutation, there are totally four phase differences between...
A method of adding squared signals of three polarization diversity receiver to overcome the polarization induced fading (PIF) in the optical fibre hydrophone is proposed and experimentally verified. This triple polarization diversity receiver (tri-PDR) is first analysed and theoretically demonstrated. Then, a Mach-Zehnder interferometric sensor with polarization rotator in the reference arm is fabricated...
A high-quality nanolayer graphene (NLG) coated hollow core fiber (HCF) platform has been demonstrated for accurate monitoring of refractive index (RI) changes so far mainly operate in liquids but not in air. The NLG with high index is deposited on the outer surface of the HCF, and an enhanced anti-resonant reflecting guidance is formed, which induces sharp periodic lossy dips in the transmission spectrum...
In this paper, a kind of theoretical method of how to find out the dominant cladding modes in the all in-fiber interferometer is proposed. The relationship between the cladding modes spatial frequency and its modal order and sensing optical fiber length are simulated. It can be found that the fiber length increasing can make the value of the dominant cladding spatial frequency linearly increase. The...
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