77 research outputs found
Dynamical regimes in a monolithic passively mode-locked quantum dot laser
Operation regimes of a two section monolithic quantum dot (QD) mode-locked laser are studied experimentally and theoretically, using a model that takes into account carrier exchange between QD ground state and 2D reservoir of a QD-in-a-well structure, and experimentally. It is shown analytically and numerically that, when the absorber section is long enough, the laser exhibits bistability between laser off state and different mode-locking regimes. The Q-switching instability leading to slow modulation of the mode-locked pulse peak intensity is completely eliminated in this case. When, on the contrary, the absorber length is rather short, in addition to usual Q-switched mode-locking, pure Q-switching regimes are predicted theoretically and observed experimentally
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Dynamical regimes in a monolithic passively mode-locked quantum dot laser
Operation regimes of a two section monolithic quantum dot (QD)
mode-locked laser are studied experimentally and theoretically, using a model
that takes into account carrier exchange between QD ground state and 2D
reservoir of a QD-in-a-well structure, and experimentally. It is shown
analytically and numerically that, when the absorber section is long enough,
the laser exhibits bistability between laser off state and different
mode-locking regimes. The Q-switching instability leading to slow modulation
of the mode-locked pulse peak intensity is completely eliminated in this
case. When, on the contrary, the absorber length is rather short, in addition
to usual Q-switched mode-locking, pure Q-switching regimes are predicted
theoretically and observed experimentally
Time-bin entanglement at telecom wavelengths from a hybrid photonic integrated circuit
Mass-deployable implementations for quantum communication require compact,
reliable, and low-cost hardware solutions for photon generation, control and
analysis. We present a fiber-pigtailed hybrid photonic circuit comprising
nonlinear waveguides for photon-pair generation and a polymer interposer
reaching 68dB of pump suppression and photon separation with >25dB polarization
extinction ratio. The optical stability of the hybrid assembly enhances the
quality of the entanglement, and the efficient background suppression and
photon routing further reduce accidental coincidences. We thus achieve a
96(-8,+3)% concurrence and a 96(-5,+2)% fidelity to a Bell state. The generated
telecom-wavelength, time-bin entangled photon pairs are ideally suited for
distributing Bell pairs over fiber networks with low dispersion
Herr Seminardirektor Ferd. Lentz in Karlsruhe und die "Allgemeine Deutsche Lehrerzeitung"
Über die Notwendigkeit des französischen Sprachunterrichts in den Lehrerseminaren : Vortrag, auf der 8. Hauptversammlung des Allg. Sachsischen Lehrervereins zu Chemnitz den 30. Sept. 1889
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