A novel kind of optical fiber Raman amplifiers using time-division-multiplexed (TDM) pumping is analyzed. The equations governing the evolution of the pumps and signals are presented for both TDM forward and TDM backward pumping. Simulation results show that the performance in gain profile and ASE noise figure can be effectively improved. The optimal TDM pump repetition rates are between 2 and 8 MHz.
A novel configuration for the transducer of magnetostrictive fiber-optic sensors was proposed and implemented. It is composed of a rectangle and two half-circles. The transducer with the novel configuration has not only higher sensitivity than that of traditional configurations, but good directivity. The magnetostriction was analyzed compared with that of cylindrical transducers. It is shown that the system sensitivity can be improved by increasing the long-side of rectangle and shortening the perimeters of the two half-circles.
Two transducers with cylindrical and racetrack configurations were fabricated. Moreover, an experimental setup to measure the low-intensity magnetic field detection responses was built up. Experimental results verified the analysis.
For its good directivity, three of them can be compounded as a vector magnetometer to measure three orthogonal components of magnetic field.
In this paper, a novel semi-analytical algorithm for calculating backward-pumped Raman amplifier is proposed. The algorithm does not need iteration and can greatly save the computational time. Simulation results for Raman amplifiers with 25 km and 50 km fibers show that the accuracy of the method is quite satisfying in comparison with the shooting algorithm and the deviation is within 0.02 dB.
A novel fast tunable electro-optic (EO) polymer waveguide grating is proposed and designed. Its resonant wavelength can be linearly tuned by first-order EO effect with a high sensitivity of 6.1pm/V. Its spectrum characteristics depend strongly on many grating parameters, such as refractive index modulation, modulation function, grating period and period number. Material selection, fabrication technology, EO tuning ability and polarization dependence of EO polymer waveguide grating are also discussed. This waveguide grating not only overcomes the shortages of optic fiber gratings, such as slow wavelength tuning ability, and large-scale integration inconveniency, but has many advantages, such as high resonant wavelength tune sensitivity, same fabrication technology as semiconductor, and polarization independence.