Dynamic saturation in semiconductor optical amplifiers: accurate model, role of carrier density, and slow light

We developed an improved model in order to predict the RF behavior and the slow light properties of the SOA valid for any experimental conditions. It takes into account the dynamic saturation of the SOA, which can be fully characterized by a simple measurement, and only relies on material fitting parameters, independent of the optical intensity and the injected current. The present model is validated by showing a good agreement with experiments for small and large modulation indices.Comment: 9 pages, 5 figure

Spectral signature of nonlinear effects in semiconductor optical amplifiers

Optical spectra of signals at the output of semiconductor optical amplifiers (SOA) provide useful insight into amplifier nonlinearities. In this work, we determine the parameters of an analytical SOA model with a pump-probe experiment by evaluating the measured spectra of the pump and probe pulses at the SOA output. The analytical lumped SOA model considers carrier depletion, carrier recovery, spectral hole burning, two-photon absorption, and we include an additional effect termed ‘two-photon induced free-carrier absorption’, that is responsible for creating an identifiable blue-shifted component in the spectra. We are able to relate the underlying physical nonlinear effects to the spectral peculiarities of the output pump and probe spectra, and give guidelines for the exploitation of these nonlinear effects for optical signal processing. In addition, with a much-simplified SOA model and by replacing the pump pulse with modulated data we show that the output spectrum is altered in a manner consistent with phase patterning effects

Tridentate Directing Groups Stabilize 6-Membered Palladacycles in Catalytic Alkene Hydrofunctionalization

Removable tridentate directing groups inspired by pincer ligands have been designed to stabilize otherwise kinetically and thermodynamically disfavored 6-membered alkyl palladacycle intermediates. This family of directing groups enables regioselective remote hydrocarbofunctionalization of several synthetically useful alkene-containing substrate classes, including 4-pentenoic acids, allylic alcohols, homoallyl amines, and bis-homoallylamines, under Pd(II) catalysis. In conjunction with previous findings, we demonstrate regiodivergent hydrofunctionalization of 3-butenoic acid derivatives to afford either Markovnikov or anti-Markovnikov addition products depending on directing group choice. Preliminary mechanistic and computational data are presented to support the proposed catalytic cycle

Efficient modulation cancellation using reflective SOAs

Modulation cancellation and signal inversion are demonstrated within reflective semiconductor optical amplifiers. The effect is necessary to implement colorless optical network units for network end-users, where downstream signals need to be erased in order to reuse the carrier for upstream transmission. The results presented here indicate that reflective semiconductor optical amplifiers possess the perfect high-speed all-optical gain saturation characteristics to completely cancel the downstream modulation at microwatt optical power levels and are thus the prime candidate to be constituents of future optical network units. Theoretical considerations are supported by experiments that show the cancellation of signals with a 6 dB extinction ratio at 2.5 Gbit/s

Enhanced optical frequency comb generation by pulsed gain-switching of optically injected semiconductor lasers

We report on the experimental generation of broad and flat optical frequency combs (OFC) in a 1550 nm laser diode using gain switching with pulsed electrical excitation together with optical injection. The combination of both techniques allows the generation of high-quality OFCs at a repetition frequency of 500 MHz, showing a low-noise optical spectrum with unprecedent features in terms of width (108 tones within 10 dB) and flatness (56 tones within 3 dB) in comparison with those previously reported for this modulation frequency. The influence of the injection conditions on the OFC quality is studied. Using these two techniques, it has been possible to reduce the separation between tones, generating high spectral performance OFCs with a repetition rateof 100 MHz.Ministerio de Economia y Competitividad of Spain (TEC201565212-C3-1-P, TEC201565212- C3-2-P)

Joh. Niclas Quillen, gewesenen Predigers zu Wolffenhausen an der Langen-Heck in der Graffschafft Wied-Runckel, Anitzo Weg-Weisers zu dem Brunnen des Lebens zu Eckhardshausen, in der Graffschaft Büdingen, Send-Schreiben An seine Hinterlassene wertheste Brüder und Schwestern, durch den Geist des Herrn Jesu gezeuget, zu Wolffenhausen und hin und wieder in der Grafschafft Wied-Runckel, Als Zeugen des Lammes in Säcken

JOH. NICLAS QUILLEN, GEWESENEN PREDIGERS ZU WOLFFENHAUSEN AN DER LANGEN-HECK IN DER GRAFFSCHAFFT WIED-RUNCKEL, ANITZO WEG-WEISERS ZU DEM BRUNNEN DES LEBENS ZU ECKHARDSHAUSEN, IN DER GRAFFSCHAFT BÜDINGEN, SEND-SCHREIBEN AN SEINE HINTERLASSENE WERTHESTE BRÜDER UND SCHWESTERN, DURCH DEN GEIST DES HERRN JESU GEZEUGET, ZU WOLFFENHAUSEN UND HIN UND WIEDER IN DER GRAFSCHAFFT WIED-RUNCKEL, ALS ZEUGEN DES LAMMES IN SÄCKEN Joh. Niclas Quillen, gewesenen Predigers zu Wolffenhausen an der Langen-Heck in der Graffschafft Wied-Runckel, Anitzo Weg-Weisers zu dem Brunnen des Lebens zu Eckhardshausen, in der Graffschaft Büdingen, Send-Schreiben An seine Hinterlassene wertheste Brüder und Schwestern, durch den Geist des Herrn Jesu gezeuget, zu Wolffenhausen und hin und wieder in der Grafschafft Wied-Runckel, Als Zeugen des Lammes in Säcken ([1]) Titelseite ([1]) Text ([3]

De Iudiciis Censoriis, Vulgo Ruge-Gerichten Speciatim De Iis, Quae In Dynastia Wedano-Rocaliensi Semel Per Annum Solemniter Celebrantur

Marburg, Univ., Jur. Diss., 1758Autopsie nach Ex. der SBB und der ULB Sachsen-AnhaltVorlageform des Erscheinungsvermerks: Marbvrgi Cattorvm Typis Philippi Casimiri Mülleri Acad. Typogr