Rugged all-fibre endless polarisation controller

Neural networks as a tool for recognition of partial discharges

“…In these formulas, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] is the electrooptical constant [14], no is the ordinary refractive index of LiNbO3 (= 2.2125 for X = 1523 nm), E,, and E,, represent the x-and y-components of the external electrical field strength, respectively, caused by the voltage differences between the electrodes while w and c are the frequency and velocity of light in vacuum. Since the two waves propagate with different phase velocities, they show a phase retardation r at the output of the waveguide which is described by:…”

“…From these techniques the one using a polarization controller yields the best receiver sensitivity. Until now mechanical polarization controllers have been realized, using electrical fiber squeezers, fiber cranks which can be rotated or polarization preserving fibers wound around piezo-electrical cylinders [7]- [9]. To keep receivers small, reliable and operating at low voltages (< 100 V), however, an integrated broad-band optical polarization controller on a lithium niobate (LiNb03) substrate [lo], [11] is the most likely candidate for future production.…”

DPSK coherent field demonstration system, and use of optical amplifier repeaters

“…However, two new features were essential to allow this demonstration to take place outside the laboratory, namely miniaturised external cavity lasers [8] and automated endless polarisation control [ 9 ] . These developments are described first, followed by an account of the system experiment using installed cable.…”