Browsing by Subject "Phase relation"

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    Generation of parabolic bound pulses from a Yb-fiber laser
    (Optical Society of American (OSA), 2006) Ortaç, B.; Hideur, A.; Brunel, M.; Chédot, C.; Limpert J.; Tünnermann, A.; Ilday F.Ö.
    We report the observation of self-similar propagation of bound-state pulses in an ytterbium-doped double-clad fiber laser. A bound state of two positively chirped parabolic pulses with 5.4 ps duration separated by 14.9 ps is obtained, with 1.7 nJ of energy per pulse. These pulses are extra-cavity compressed to 100 fs. For higher pumping power and a different setting of the intra-cavity polarization controllers, the laser generates a bound state of three chirped parabolic pulses with different time separations and more than 1.5 nJ energy per pulse. Perturbation of this bound state by decreasing pump power results in the generation of a single pulse and a two-pulse bound state both structures traveling at the same velocity along the cavity. A possible explanation of the zero relative speed by a particular phase relation of the bound states is discussed. ©2006 Optical Society of America.
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    Using phase relations in microstrip directional couplers to achieve high directivity
    (2013) Tas, V.; Atalar, Abdullah
    We analyze the microstrip directional couplers with a special focus on the phase difference between the coupled and isolated ports. The analysis uses the even-odd mode decomposition technique and network theory. The results show that the phase difference between the signals at the coupled port and the isolated port is close to \pi in a very wide band. This property can be used to achieve a broadband directivity by inducing a voltage cancellation at the isolated port of the couplers. Two different cancellation methods are investigated. Analytical formulas for the required component values of both methods are given. Higher directivity can be obtained at the expense of reduced bandwidth.