Photonic synthesis of radiofrequency revived the quest for unrivalled microwave purity by its seducing ability to convey the benefits of the optics to the microwave world 1-11 . In this work, we perform a high-fidelity transfer of frequency stability between an optical reference and a microwave signal via a low-noise fiber-based frequency comb and cuttingedge photo-detection techniques. We demonstrate the generation of the purest microwave signal with a fractional frequency stability below 6.5 x 10 -16 at 1 s and a timing noise floor below 41 zs.Hz -1/2 (phase noise below -173 dBc.Hz -1 for a 12 GHz carrier). This outclasses existing sources and promises a new era for state-of-the-art microwave generation. The characterization is achieved through a heterodyne cross-correlation

He C., Wei Y. D. and Xie X. Globalization, institutional change, and industrial location: economic transition and industrial concentration in China, Regional Studies. Marketization and globalization in China may stimulate industrial clustering, while decentralization may lead to protectionism and industrial dispersion. This paper examines industrial distribution in China during 1980-2003. While Chinese industries have been increasingly concentrated geographically, the study found significant temporal and sectoral variations in concentration. Least protected industries have become increasingly concentrated, and most globalized industries are clustered in the coastal region. The analysis indicates that globalization and internal scale economies have contributed to geographical concentration, while protectionism has hindered industrial specialization. While industries are more likely to locate based on comparative advantages, external scale economies have not fostered industrial concentration. [image omitted] He C., Wei Y. D. et Xie X. La mondialisation, la transformation institutionnelle, et la localisation industrielle: la mutation economique et la concentration industrielle en Chine, Regional Studies. Il se peut que la commercialisation et la mondialisation en Chine encouragent l'etablissement de grappes industrielles, alors que la decentralisation amene au protectionnisme et a la dispersion industrielle. Cet article cherche a examiner la distribution industrielle en Chine entre 1980 et 2003. Tandis que l'industrie chinoise se concentre de plus en plus, il s'avere que cette concentration varie sensiblement des points de vue temporel et sectoriel. L'industrie la moins protegee se concentre de plus en plus et l'industrie la plus mondialisee s'agglomere pour la plupart dans la zone cotiere. L'analyse laisse voir que la mondialisation et les economies d'echelle internes ont contribue a la concentration geographique, alors que le protectionnisme a entrave la specialisation industrielle. Pendant que l'industrie se localise en fonction de l'avantage comparatif, les economies d'echelle externes n'encouragent pas la concentration industrielle. Mutation economique Mondialisation Decentralisation Agglomeration Concentration geographique Chine He C., Wei Y. D. und Xie X. Globalisierung, institutioneller Wandel und Industriestandorte: wirtschaftlicher Wandel und industrielle Konzentration in China, Regional Studies. Die Marktorientierung und Globalisierung in China kann sich fordernd auf die industrielle Clusterbildung auswirken, wahrend eine Dezentralisierung zu Protektionismus und industrieller Streuung fuhren kann. In diesem Beitrag untersuchen wir die industrielle Verteilung in China im Zeitraum von 1980 bis 2003. Die chinesischen Industrien haben sich geografisch zunehmend konzentriert, doch zugleich finden wir signifikante zeitliche und sektorale Schwankungen hinsichtlich der Konzentration. Die am wenigsten geschutzten Industrien haben sich zunehmend konzentriert, wahrend die am starksten globalisierten Industrien in Cl...

A widely tunable optoelectronic oscillator (OEO) based on a broadband phase modulator and a tunable optical bandpass filter is proposed and experimentally demonstrated. A tunable range from 4.74 to 38.38 GHz is realized by directly tuning the bandwidth of the optical bandpass filter. To the best of our knowledge, this is the widest fundamental frequency tunable range ever achieved by an OEO. The phase noise performance of the generated signal is also investigated. The single-sideband phase noise is below -120 dBc/Hz at an offset of 10 KHz within the whole tunable range.

Phase noise or frequency noise is a key metrics to evaluate the short term stability of a laser. This property is of a great interest for the applications but delicate to characterize, especially for narrow line-width lasers. In this letter, we demonstrate a digital cross correlation scheme to characterize the absolute phase noise of subhertz line-width lasers. Three 1,542 nm ultra-stable lasers are used in this approach. For each measurement two lasers act as references to characterize a third one. Phase noise power spectral density from 0.5 Hz to 0.8 MHz Fourier frequencies can be derived for each laser by a mere change in the configuration of the lasers. This is the first time showing the phase noise of sub-hertz linewidth lasers with no reference limitation. We also present an analysis of the laser phase noise performance.Laser phase noise describes how the phase of a laser output electrical field deviates from an ideal sinusoidal wave. This quantity which is defined to evaluate the short term stability of a laser can also be used to estimate the line-width or coherent length of a laser. In many applications, such as coherent optical communication [1], LIDAR [2], optical fiber-based interferometeric sensors [3], high resolution spectroscopy [4], ultra-low phase noise photonic microwave generation [5], and optical atomic clock [6], the laser phase noise can profoundly impacts the limitation of a system. Thus, lasers with ultra-low phase noise are actively studied [7][8][9][10]; while the precise characterization of such ultrastable laser is becoming more important.Phase noise characterization is a comparison process. Generally, laser phase noise measurement approaches can be divided into two categories according to the comparison method. The first one is comparing the laser under test with itself through the schemes of delayed self-homodyne, delayed self-heterodyne [11,12] or Michelson interferometer [13]. Several kilometers of fiber are usually used for these optical delay line methods in order to make the delay time longer than the laser coherent time. It is difficult to characterize the phase noise of lasers with hundreds-hertz linewidth or narrower via these delay line technique as thousands of kilometers of fiber would be required, and the fiber noise itself can also become a limitation. The second category, which is called the beat-note method [14][15][16][17], implies comparing the laser under test with a reference laser whose phase noise is much lower than that of the one under test. When the phase noise of the laser under test is lower than that of any available reference, two similar lasers must be built and compared. Assuming statistical independence and equal contribution of both lasers, the phase noise is revealed after division of the beat-note phase noise by √2. However, to realize two equally good lasers is not straightforward. Cross correlation is a well know approach to characterize the phase noise of RF and microwave oscillators with ultra-low level [5,[18][19][20][21][22]. Here, we extend ...