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ABSTRACT: We report the fabrication, characterization and application of extremely short linear-cavity distributed Bragg reflector fibre lasers (DBR-FLs) written in commercial erbium-doped fibres. The DBR-FL has a total length of 7 mm, of which the nominal cavity is 0.4 mm in length, making it the shortest DBR-FL being reported. Two distinct spectral properties are observed: ultra-narrow linewidth and ultra-low polarization beat frequency, which are measured to be 0.22 kHz and 18.9 MHz, respectively. For the former, the FLs find applications in high sensitivity interferometric sensing, optical frequency metrology and coherent optical communications, whereas for the latter, such a low beat frequency is beneficial to the construction of low-cost and simple demodulator electronics for sensor signal demodulation. The relative intensity noise measurement showed that the relaxation oscillation frequency and relative peak are 120 kHz and −75 dB Hz−1, respectively. The FL exhibited low-noise characteristics, with an intensity noise of −107 dB Hz−1 at 1 MHz. We demonstrate the use of these extremely short FLs in the construction of an efficiently pumped and serially multiplexed FL sensor array suitable for practical sensing applications. Two array configurations were tested, namely with individual FLs fabricated in short sections of EDF and connected via passive fibres and with all FLs fabricated along a single EDF.
Measurement Science and Technology 02/2011; 22(4):045202. · 1.49 Impact Factor
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ABSTRACT: Fiber Bragg gratings in pure-silica polarization-maintaining photonic crystal fiber were photowritten by use of two-photon ultraviolet excitation and characterized for their responses to temperature, axial strain, and hydrostatic pressure. The two resonance wavelengths corresponding to the two polarization axes show the same response to temperature and axial strain but different response to hydrostatic pressure. The differential pressure sensitivity is independent of temperature.
IEEE Photonics Technology Letters 01/2009; · 2.19 Impact Factor
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ABSTRACT: We report on fiber Bragg gratings in all-solid photonic bandgap fiber that composed of a triangular array of high-index Ge-doped rods in pure silica background with fluorine-doped index-depressed layer surrounding the Ge-doped rod. Fiber Bragg gratings were photowritten with 193 nm ArF excimer laser and characterized for their response to strain, temperature, bending and torsion. These gratings couple light from the forward core mode to not only backward core mode but also backward rod modes. This results in multiple resonance peaks in the reflection spectrum. All resonance wavelengths exhibited the same temperature and strain response with coefficient similar to that of Bragg gratings in standard single-mode fiber. The strength of the resonance peaks corresponding to the backward rod modes showed high sensitivity to bending and torsion.
Optical Fiber Sensors Conference, 2008. APOS '08. 1st Asia-Pacific; 12/2008
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ABSTRACT: We present a high-temperature-resistant distributed Bragg reflector fiber laser photowritten in Er/Yb codoped phosphosilicate fiber that is capable of long-term operation at 500 degrees C. Highly saturated Bragg gratings are directly inscribed into the Er/Yb fiber without hydrogen loading by using a 193 nm excimer laser and phase mask method. After annealing at elevated temperature, the remained gratings are strong enough for laser oscillation. The laser operates in robust single mode with output power more than 1 dBm and signal-to-noise ratio better than 70 dB over the entire temperature range from room temperature to 500 degrees C.
Optics Express 04/2008; 16(5):2958-64. · 3.59 Impact Factor
