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Now showing items 1 - 16 of 68


    The present invention provides an optical signal processing device having a transponder aggregator function that does not increase fundamental loss regardless of the increase of the number of necessary transponders. Optical signals inputted from input ports (a, b, c) are inputted to a PLC (10). In the PLC (10), SBTs (11_0 to 11_4) are installed, the input ports (a, b, c) are connected to the input-side SBT (11_0), and planar waves are outputted at different angles for each of the input ports from an output end of the PLC (10) to the space side. The optical paths of the optical signals outputted from the PLC (10) are converted within an x-z plane by a cylindrical lens (Lsp) having a refraction action in an x-axis direction, and the optical signals are reflected in different regions that are regions (A, B, C) on an LCOS according to the positions of the input ports (a, b, c). The reflected optical signals are incident on the SBTs (11_1 to 11_4) on the output side of the PLC (10), and outputted to output ports (1-4) via merging parts (13_1 to 13_4).
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    Provided is an organic light emitting element which exhibits stable performance in the atmosphere. This organic light emitting element comprises a positive electrode, a negative electrode and a first organic compound layer that is arranged between the positive electrode and the negative electrode. This organic light emitting element also comprises a first organic compound layer that is arranged between the negative electrode and a light emitting layer and a second organic compound layer that is arranged between the light emitting layer and the first organic compound layer and is in contact with the first organic compound layer. The first organic compound layer contains a first organic compound, and the second organic compound layer contains a second organic compound. The first organic compound is an organic compound represented by general formula [1], and the second organic compound is an organic compound that is different from the first organic compound.
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    Provided is an organic light emitting device having high emission efficiency and a long continuous driving lifetime. The organic light emitting device includes: an anode; a cathode; and an emitting layer placed between the anode and the cathode, in which: the emitting layer contains an emitting material that emits fluorescence; and in an emission wavelength region of the emitting material, an absorption peak of an absorption spectrum in a minimum excited triplet state of a material having a smallest minimum excited triplet energy out of constituent materials in the emitting layer is absent.
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    This semiconductor element is equipped with: an active region, which has a first conductivity-type emitter region that is provided on the upper surface side of a first conductivity-type substrate, a second conductivity-type base region that is provided on the upper surface side of the substrate, and a second conductivity-type collector layer that is provided on the lower surface side of the substrate; and a diode region, which has a second conductivity-type anode layer that is provided on the upper surface side of the substrate, and a first conductivity-type cathode layer that is provided on the lower surface side of the substrate. The cathode layer is separated from the active region in a plan view, and on the upper surface side of the active region, a second conductivity-type high-concentration region having an impurity concentration higher than that of the anode layer is formed.
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  • Low-Loss Transponder Aggregator Using Spatial and Planar Optical Circuit

    Ikuma, Yuichiro   Suzuki, Kenya   Nemoto, Naru   Hashimoto, Etsu   Moriwaki, Osamu   Takahashi, Tetsuo  

    We propose a compact transponder aggregator (TPA) consisting of a wavelength selective switch (WSS) array and a direction switch array. It has no intrinsic splitting loss and therefore the number of ports can exceed that of a conventional multicast switch. Awaveguide-based frontend that incorporates spatial beam transformers enables us to increase the number of ports and integrate multiple WSSs in a simple optical system. The direction switch array is integrated in the frontend. We describe an 8 x 24 prototype, which is the largest port count yet achieved for a TPA with no intrinsic splitting loss.
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    Provided is an optical switch which suppresses deterioration due to crosstalk caused by imperfect spatial light modulation elements. This optical switch includes at least one input port, at least one output port, and a spatial light modulation unit in which the optical signal from the input port is incident and which deflects the optical signal to a selected output port of the output ports. In the spatial light modulation unit, multiple phase distribution units are configured continuously in the switching axis direction, and each of the phase distribution units has one region in which the phase modulation amount increases linearly in accordance with the position of incidence of the signal light onto the spatial light modulation unit, and one region in which the phase modulation amount decreases linearly. The region in which the phase modulation amount increases linearly is larger than the region in which the phase modulation amount decreases linearly, the slope of increase of the phase in one of the phase distribution units is the same as the slope of increase of the phase in an adjacent phase distribution unit, and the period of one of the phase distribution units is configured to be different from the period of an adjacent phase distribution unit.
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    Aspects of the present invention provide a blue organic light-emitting device having a continuous operation lifetime. An organic light-emitting device includes a light-emitting layer containing a dopant having the ability to trap electrons or holes, and a hole- blocking layer or electron-blocking layer, in which the difference between the LUMO of the dopant and the LUMO of a host material, the size relationship between the HOMO of the host material and the HOMO of the dopant, and the difference between the T1 of the host material and the T1 of the hole-blocking layer or between the T1 of the host material and the T1 of the electron-blocking layer, are specified.
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  • Wide-Range Variable Gain Fiber Amplifier With Erbium-Doped Fiber Switching

    Ono, Hirotaka   Watanabe, Toshio   Suzuki, Kenya   Mori, Atsushi   Takahashi, Tetsuo   Sakamoto, Tadashi  

    A variable gain erbium-doped fiber amplifier (EDFA) with a wide gain range and a small noise figure (NF) variation is analyzed numerically and demonstrated experimentally. The EDFA can change the total erbium-doped fiber length by selecting six combinations of three EDFs with optical switches (SWs). The numerical calculation of the NF and the pump power using the analytical model of an EDFA indicates that such a variable gain EDFA has an advantage over a conventional multi-stage EDFA in terms of NF variation and required pump power. These characteristics are demonstrated by constructing a variable gain EDFA that employs SWs and variable optical attenuators (VOAs) integrated on a silica-based planar lightwave circuit (PLC). The variable gain EDFA exhibits a smaller NF variation of 1.2 dB for the 24-dB variable gain range than conventional two-and four-stage EDFAs, which have NF variations of 12.6 and 2.0 dB, respectively, for the same variable gain range. The power consumption of these EDFAs is also discussed by comparing the operating electric power of the SWs and VOAs with that of the pump laser.
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    The present invention provides a novel fused polycyclic compound suitably used for a blue light emitting element and an organic light emitting element including the fused polycyclic compound. A fused polycyclic compound is represented by at least one of the general formulas [1] and [2] according to Claim 1. In the general formulas [1] and [2], R1 to R20 each represent a hydrogen atom or a substituent.
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    This intrusion prevention device (10) receives from a device to be controlled (30) a notification indicating the state of the device to be controlled (30). The intrusion prevention device (10) additionally receives a control command which has been transmitted from a control device (20) to the device to be controlled (30). Upon receiving the control command, the intrusion prevention device (10) assesses whether to allow or to block the passage therethrough of the control command, according to the received state of the device to be controlled (30).
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    Provided is a multiplex transmission system which adds a managing overhead to a client signal and multiplexes or contains the client signal in a transparent for transmission. The multiplex transmission system contains a plurality of client signals having different bit rates including client signals other than a signal having a bit rate multiplied or divided by an integer and adjusts some or all of the client signals so that the their bit rates are equal to the other client signals which are multiplied or divided by integers.
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  • Pump Light Source for Distributed Raman Amplification in MCFs With LD Sharing Circuit

    Suzuki, Kenya   Ono, Hirotaka   Mizuno, Takayuki   Hashizume, Yasuaki   Abe, Yoshiteru   Takahashi, Tetsuo   Takenaga, Katsuhiro   Matsuo, Shoichiro   Takara, Hidehiko  

    We report an integrated pump source for distributed Raman amplification (DRA) in multicore fiber (MCF) where the MCF cores share pump laser diodes (LDs). The DRA requires many LDs and passive components if it is to obtain a flat and polarization-insensitive gain spectrum, especially in MCF transmission. To reduce the number of optical components, we propose a pump configuration where two cores share a pump LD set. The number of LDs is reduced almost by half. We integrate passive components, such as wavelength division multiplexers and polarization beam combiners, in a planar lightwave circuit to realize the LD sharing circuit. With our proposed pump sharing configuration, we obtain a DRA gain of more than 5.7 dB over the entire C-band in an MCF.
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  • Ambipolar light-emitting transistors of a tetracene single crystal

    Takahashi, Tetsuo   Takenobu, Taishi   Takeya, Jun   Iwasa, Yoshihiro  

    The first ambipolar light-emitting transistor of an organic molecular semiconductor single crystal, tetracene, is demonstrated. In the device configuration, electrons and holes injected from separate magnesium and gold electrodes recombined radiatively within the channel. By varying the applied voltages, the position of the recombination/emission zone could be moved to any position along the channel. Because of the changes made to the device structure, including, the use of single crystals and polymer dielectric layers and the adoption of an inert-atmosphere fabrication process, the set of materials that can be used for light-emitting transistors has been expanded to include monomeric molecular semiconductors.
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  • Electron transport in rubrene single-crystal transistors RID A-7097-2008 RID G-9009-2011

    Bisri, Satria Zulkarnaen   Takenobu, Taishi   Takahashi, Tetsuo   Iwasa, Yoshihiro  

    We report a study of impurity effects on the electron transport of rubrene single crystals. A significant improvement of electron carrier mobility up to 0.81 cm(2)/V s is achieved by performing multiple purifications of single crystals and device aging inside an N(2)-filled glove box. The hole/electron mobility ratio obtained is in good agreement with the reported theoretical calculation, suggesting that the intrinsic electron transport of organic semiconductors is also exploitable in a manner similar to that of hole transport. (C) 2010 American Institute of Physics. [doi:10.1063/1.3419899]
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  • Recent Development and Future Prospects of Optical Metro Networks and their Technologies

    Inui, Tetsuro   Sahara, Akio   Takahashi, Tetsuo  

    This paper describes the broadband situation in Japan and the recent development of optical metro networks, their future prospects and technologies. First, the situation as regards the broadband infrastructure and internet traffic in Japan is overviewed. Then, the recent development of reconfigurable optical add drop multiplexers (ROADMs) in optical metro networks is reviewed. Finally, the future prospects for optical metro networks are described with particular emphasis on 100Gbit/s standardization, sub-lambda function, and colorless/directionless ROADMs.
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  • Evolution of photonic network technologies

    Takahashi, Tetsuo  

    This paper describes photonic network technologies from the viewpoint of optical switching functionality and photonic network transparency, and presents an analysis of the various types of current photonic nodes. The analysis results show that the most important choice is whether or not the photonic network node system is constructed in an optically transparent manner. This paper also describes various types of photonic node architecture. Regarding the optical add drop multiplexing (OADM) system, the merits of the reconfigurable OADM (ROADM) are precisely analyzed.
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