High peak power laser systems of up to petawatt [1] are based on chirped pulse amplification (CPA) technique [2]. In the CPA laser system, ultrashort pulses from an oscillator are first stretched below the nonlinear pulse distortion threshold to reduce the peak power and the amplified pulses are recompressed at the output by a compressor. Stable ultrashort pulse oscillator is necessary for CPA ...

This paper demonstrates, for the first time to our best knowledge, the application of a tunable external-cavity fiber Bragg grating diode laser in spectroscopic chemical sensing. A tunable fiber Bragg grating external-cavity semiconductor laser is demonstrated with over 10 nm of tuning range. A piezo-actuator was implemented to stretch the grating for rapid wavelength tuning of the laser. The a...

We have measured the refractive index change (RIC) induced in a fiber Bragg grating (FBG) written in a Yb-doped fiber amplifier (YB-FBG) because of the amplifier pumping. The measurement was performed by exploiting the high sensitivity of the YD-FBG transmission to the RIC. We have separated between electronic and thermal contributions to the RIC based on the difference between the time-scales ...

We report results from a fiber Bragg grating (FBG) based scheme for vibration sensing in combustion engines. The vibration sensing is carried out using a commercial high speed spectrometer. We compare the performance of the FBG sensor with commercial PZT-based sensors and find that the FBGs perform as well.

We report the fabrication and characterization of a fiber Bragg grating (FBG) with 870 nm resonance wavelength in a single-mode TOPAS microstructured polymer optical fiber (mPOF). The grating has been UV-written with the phasemask technique using a 325 nm HeCd laser. The static tensile strain sensitivity has been measured as 0.64 pm/μstrain, and the temperature sensitivity was -60 pm/C. This is...

Chirped fiber Bragg grating (CFBG) provides an attractive solution for low cost dispersion compensation in a fiber optic transmission system. This kind of grating can be produced with a large chirp parameter and period sampled distribution along the grating length. The present work carries out the design optimization of a chirped FBG in respect of chirp bandwidth and apodization in achieving op...

High temperature is one of the important reasons causing the fire in power system. Therefore, the early warning could be told by monitoring the temperature and effective measures could be taken. The corresponding accidents will be reduced. The traditional transformer winding temperature monitoring methods are electrical signal measurement and infrared measurement. Such electrical signal sensors...

Fiber Bragg grating (FBG) is fabricated in the microfiber by the use of femtosecond laser pulse irradiation. Such a grating can be directly exposed to the surrounding medium without etching or thinning treatment of the fiber, thus possessing high refractive index (RI) sensitivity while maintaining superior reliability. The grating in the microfiber may have a number of propagation modes in its ...

We present a new type of fiber Bragg grating (FBG) in which we etch the grating into the flat surface of a D-shaped optical fiber. Instead of being written in the core of the fiber, as are standard FBGs, these surface-relief FBGs are placed in the cladding above the core. These gratings are a viable alternative to standard FBGs for sensing applications. We describe the fabrication process for e...

Fiber Bragg Grating (FBG) sensors are among the most popular elements for fiber optic sensor networks used for the direct measurement of temperature and strain. Modern FBG interrogation setups measure the FBG spectrum in real-time, and determine the shift of the Bragg wavelength of the FBG in order to estimate the physical parameters. The problem of determining the peak wavelength of the FBG fr...