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The optical transport network (OTN) based on 43-Gb/s channels is expected to be the carriers' next-generation core network. This paper discusses its system architecture, from the requirements of services, protection, and management, and shows a feasible scenario to ensure the rapid penetration of the 43-Gb/s-based OTN. It also describes the design concept and functions of the first 43-Gb/s OTN line terminal. The line terminal deploys time-division multiplexing to handle client signals and provides high-quality, multiple transparent services, such as synchronous optical network/synchronous digital hierarchy and gigabit Ethernet. The configuration and features of the actual fabricated system are described. [ABSTRACT FROM PUBLISHER]

We show the advantages of distributed erbium-doped fiber amplifiers (EDFAs) over lumped EDFAs. Using the distributed EDFA for 50%-100% of the transmission line lessens the signal degradation compared to the conventional transmission line. We also show the feasibility of the gain-flattened d-EDFA transmission line. An experiment shows that the gain peak is shifted and flattened at low pump powers [ABSTRACT FROM PUBLISHER]

This paper proposes a novel adaptive dispersion equalization system that equalizes the temperature-induced dispersion fluctuation in long-span ultra-high-speed optical transmission systems. The system monitors the dispersion fluctuation by measuring the relative delay between two wavelength division multiplexed (WDM) signals, and equalizes the dispersion fluctuation by wavelength tuning. A variable-dispersion equalizer can be used instead of wavelength tuning. Adaptive equalization is successfully demonstrated in 40-Gb/s (8-ps-RZ pulses) 400-km transmission. Furthermore, the proposed equalization system is shown to be applicable to WDM systems that use dispersion and dispersion slope compensation. Since the sensitivity to the dispersion fluctuation is improved by extending the wavelength spacing of the signal and monitor channels, the system is shown to operate even when polarization-mode dispersion (PMD) of the transmission fiber must be taken into account [ABSTRACT FROM PUBLISHER]

Reduction of mode partition noise induced by spectral filtering of Fabry-Perot lasers is demonstrated by using a semiconductor optical amplifier (SOA). Because the SOA acts as a high-pass filter, the mode partition noise appearing at low frequencies can be suppressed. A 16-dB recovery of the signal-to-noise ratio and a 6.2-dB recovery of the Q factor are obtained [ABSTRACT FROM PUBLISHER]

This paper proposes to combine prechirping with dispersion management scheme in such a way as to suppress the power penalty induced by self-phase modulation (SPM) and cross-phase modulation (XPM) in 40-Gb/s per channel wavelength-division multiplexed (WDM) transmission systems with long-amplifier spacing. First, we show that the optimum total dispersion to minimize SPM depends on prechirping and the local dispersion of the transmission fiber, unlike that for minimizing XPM. Next, it is shown that, by optimizing the combination of prechirping and local dispersion, these two optima can be made to match so as to improve the allowable maximum fiber input power. Finally, the operation of the proposed optimization scheme is confirmed experimentally, and 4×40-Gb/s WDM transmission over 400 km of nonzero dispersion-shifted fiber (NZDSF) is demonstrated successfully with the fiber input power of +10 dBm/ch and 250 GHz channel spacing [ABSTRACT FROM PUBLISHER]

This paper presents a fully electrical 40-Gb/s time-division-multiplexing (TDM) system prototype transmitter and receiver. The input and output interface of the prototype are four-channel 10-Gb/s signals. The prototype can be mounted on a 300-mm-height rack and offers stable 40-Gb/s operation with a single power supply voltage. InP high-electron mobility transistor (HEMT) digital IC's perform 40-Gb/s multiplexing/demultiplexing and regeneration. In the receiver prototype, unitraveling-carrier photodiode (UTC-PD) generates 1 Vpp output and directly drives the InP HEMT decision circuit (DEC) without any need for an electronic amplifier. A clock recovery circuit recovers a 40-GHz clock with jitter of 220 fspp from a 40-Gb/s nonreturn-to-zero (NRZ) optical input. The tolerable dispersion range of the prototype within a 1-dB penalty from the receiver sensitivity at zero-dispersion is as wide as 95 ps/nm, and the clock phase margin is wider than 70° over almost all the tolerable dispersion range. A 100-km-long transmission experiment was performed using the prototype. A high receiver sensitivity [-25.1 dBm for NRZ (27-1) pseudorandom binary sequence (PRBS)] was obtained after the transmission. The 40-Gb/s regeneration of the InP DEC suppressed the deviation in sensitivity among output channels to only 0.3 dB. In addition, four-channel 40-Gb/s wavelength-division-multiplexing (WDM) transmission was successfully performed [ABSTRACT FROM PUBLISHER]

Low-cost plastic packaging of laser diodes and photodiodes mounted on planar lightwave circuit (PLC) platform are developed and its reliability is confirmed under various environmental and endurance tests. The high performance of the module is maintained under reliability tests, such as high-humidity high-temperature tests (85°C, 85%RH) and temperature cycling tests (-40°C/85°C). No laser diodes show any device characteristics change during environmental tests and their stability has very little dependence on current bias. Although the photodiodes show an increase in leakage current under high-temperature high-humidity tests and the rate of leakage current increase is proportional to the square root of bias voltage, the increase is negligible for system use. These plastic modules can be applied to actual access networks and other fiber-optic networks [ABSTRACT FROM PUBLISHER]

Changes in the wavelength and lamp characteristics due to the degradation of distributed Bragg reflector (DBR) lasers are investigated and the lasers are confirmed to be reliable enough for application as the light sources in WDM systems. The change in wavelength characteristics is due to degradation of the DBR or phase control region and the change in lamp characteristics is due to the degradation of active region. These changes in the characteristics are caused by diminished recombination carrier lifetime. The wavelength stability is strongly correlated with the injected current density. The lamp characteristics is confirmed to be almost as stable as in conventional Fabry-Perot lasers. The applicability of DBR lasers as the light source for wavelength division multiplexing (WDM) systems is demonstrated for actual-use conditions [ABSTRACT FROM PUBLISHER]

We clarify the impact of a bulk detection layer in an optical transceiver diode for low-cost time compression multiplexing (TCM) transmission systems. By optimizing the detection layer for both transmitter and receiver operations, we obtain temperature- and wavelength-insensitive responsivity, and the power penalty of sensitivity is within 0.55 dB over a wide-wavelength range in the receiver mode. The pulsation due to the detection layer is also effectively suppressed in the transmitter mode. We demonstrate a switching operation for 156-Mb/s nonreturn-to-zero burst signals, which is indispensable for TCM transmission systems [ABSTRACT FROM PUBLISHER]

The feasibility of using narrow-spectral-linewidth distributed-feedback lasers as subcarrier multiplexing video distribution sources in optical heterodyne FM converters is shown by investigating degradation modes of the lasers. There is no change in the dynamic properties, such as the FM response and the composite second-order and composite triple-beat figures, though spectral linewidth is increased by degradation. The main degradation appears as an increase in spectral linewidth due to 1/f noise caused by buried heterointerface degradation. The FM response, composite second-order, and composite triple-beat, however, hardly change in the degradation process [ABSTRACT FROM PUBLISHER]

Female F1 mice (BDFI: C57B1/6 × DBA/ 2, BCFI: CS7BL/6×C3H/HeN. BBF1: C578L/ 6× BA LB/c) were preimmunized with rat erythrocytes and then received splenic T cells from parental female C57BL/6 mice injected with hydrocortisone acetate before killing. In BDFI and BCF1 mice, direct Coombs' test (DCT) positivity persisted for more than 4 months in almost all mice. They also showed haematological sign of anaemia, and the survival of infused 51Cr-labelled parental C57BL/6 erythrocytes was reduced. In BBFI mice, DCT positivity returned to negative within 2 months. Autoantibodies were eluted from DCT-positive erythrocytes and their specificities were examined. They were capable of binding equally well to erythrocytes from all strains of mice tested, including the donor mice. They also cross-reacted with rat erythrocytes but not with sheep, rabbit or human erythrocytes. Isotypes of the autoantibodies eluted were also examined. Interestingly, isotypes of the autoantibodies obtained from individual mice were confined to one or other subclass of IgG isotype: lgGl, IgG2a or IgG2b. [ABSTRACT FROM AUTHOR]

Copyright of American Potato Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of American Potato Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)