Cheng H.,Beijing University of Posts and Telecommunications |
Li Y.,Beijing University of Posts and Telecommunications |
Zhang F.,Beijing University of Posts and Telecommunications |
Zhang F.,Nanjing University of Aeronautics and Astronautics |
And 3 more authors.
A pilot-symbols-aided phase unwrapping (PAPU), which utilizes the time-division multiplexed pilot symbols that are transmitted with data, is proposed to do cycle slip detection and correction with the carrier phase estimation (CPE). Numerical simulations for 10 Gbaud dual-polarization 16-ary quadrature amplitude modulation (DP-16QAM) systems show that the block averaging quadrature phase-shift keying (QPSK) partitioning with PAPU greatly eliminates the performance degradation caused by cycle slips, maintains a low CS probability with less influence of filter length, and achieves a bit-error-rate (BER) performance below soft-decision forward error correction (FEC) limit 2 × 10-2 at 15 dB optical signal-to-noise ratio with only 1.56% overhead and 6 MHz combined laser linewidth. © 2013 Optical Society of America. Source
Lian H.-Z.,FiberHome Telecommunication Technologies Co.
Guangdianzi Jiguang/Journal of Optoelectronics Laser
For the PCVD optical fiber preform manufacture system, all the ways which maybe introduce metallic ions are analyzed, such as raw material for optical preform, chemical delivery system, bubbler in the gas cabinet, and the response pipeline. Finally, the corresponding methods to prevent and reduce metallic ions for increasing the quality of the multi-mode optical fiber are given. After cleaning the metal bubblers of equipment by "Removing and Cleaning procedure for Bubblers", the A-level fibers more than 60% of all fibers for the general 62.5/125 μm multi-mode fibers. Source
Huang C.,Shanghai JiaoTong University |
Tang Y.,Shanghai JiaoTong University |
Li H.,Shanghai JiaoTong University |
Wang Y.,Shanghai JiaoTong University |
And 2 more authors.
Journal of Lightwave Technology
We have derived a model to provide a unique insight into the temperature-dependent effects in Tm-doped silica fiber lasers with consideration of important energy transfer processes and full spectra of laser transition. By fitting experimental measurements, the dependence of emission and absorption cross sections on temperature was characterized. With careful thermal management to control the influence of thermomechanical and thermooptical effects, a good agreement was achieved between simulations and experiments, even in the kilowatt power domain. On the basis of the model, the investigation shows that the thermal distribution of ions over the Stark sublevels contributes a higher threshold and a lower laser power as the temperature increase. Fortunately, this degradation of laser performance can be largely weakened when higher pump intensity is employed. The simulations also show that lower output coupling and longer operational wavelength can mitigate the output power variation arising from the temperature. The model was further used to analyze the dependence of laser spectrum on the fiber length and pump power when temperature changes. In addition, the laser output power and temperature distribution in kW-level are also studied. © 2013 IEEE. Source
Fiberhome Telecommunication Technologies Co. | Date: 2013-07-24
A maintenance method of intelligent ODN management system comprises the following steps: carrying out mutual exclusion protection on a same operation task, wherein each executable operation task is protected by operation authorization, and any one maintenance and management terminal needs to acquire the operation authorization of the operation task before executing the operation task and release the corresponding operation authorization after the execution is finished; and carrying out mutual exclusion protection on different maintenance and management terminals, wherein after a local maintenance center obtains control right on the intelligent ODN management system, a remote maintenance center and a local maintenance terminal need to apply for authorization from the local maintenance center before operating the intelligent ODN management system, and can deliver an operation instruction after successfully applying for the authorization. A system exception caused by conflicted operations is therefor effectively prevented.
Fiberhome Telecommunication Technologies Co. | Date: 2012-08-10
The present invention discloses a smart ODN system of low power consumption, and the system is related to the ODN field and includes a smart management terminal, a master control management board, and several wiring management boards, where the smart management terminal is directly connected to the master control management board, and is also connected to the master control management board through the Internet and a mobile terminal, the master control management board is connected with several wiring management boards, each wiring management board includes a PMU and a PQU, which are independent from each other, the PQU is connected to a CPU of a wiring management board through a control line; the PMU is configured to collect and store information data of a port and communicate with the master control management board or the smart management terminal; the PQU independent from the CPU independently performs the query operation on a wiring port, and promptly obtains a port connection status. The present invention more than doubles operation time of a smart ODN management system, extends battery life of the whole system when a mobile power supply provides power for the system, shortens a time span taken by the system to respond to port changes, and improves operation efficiency of the system.