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The Experimental Advanced Superconducting Tokamak is a large fusion research device which aims at long-term and high parameters plasma operation. A distributed and continuous data acquisition system based on PXI/PXI Express technology has been developed for EAST. At present the system has more than 50 data acquisition units and more than 2000 raw channels, the maximum data throughput is about 5GBytes/s. How to access the large amount of data as fast as possible becomes a big problem. So we planned to design a special hierarchical data storage system for EAST. The system is composed of 4 storage tiers. The tier1 is based on PCIe SSD storage which provide the data access cache. The tier2 is the local SAS raid on MDSplus server cluster for real-time data collection from the data acquisition units. The tier3 is Lustre storage which stored all the current campaign data and can provide fast parallel data access for data processing. The tier4 is NAS storage for historic data achieving. A schedule program is designed to control the data flow between tier1 and tier2/tier3/tier4. The system has been designed and will be adopted in the next campaign and the system details will be given in the paper.

A data acquisition and control system has been realized for a Multi-Energy Soft X-Ray (ME-SXR) diagnostic, which has been built for EAST (Experimental Advanced Superconducting Tokamak) electron temperature profile in the edge plasma region. The system has two functions: long-pulse data acquisition and electronics' automatic gain-control. It provides 96 high-speed channels with optional sampling rates from 250 KSPS to 1 MSPS, which can long-pulse acquires signals of ME-SXR. In the meanwhile, it transfers the data to the MDSplus server in real-time and users can access to the data during the discharge. The signals from the diode array detectors are in the microampere range, which should be amplified by the electronics with the transimpedance in 8 stages. In the past, electronics' gain settings were totally man-control. In order to realize auto-control, it makes data de-noising and calculates appropriate gains, according to the pulse situation and ME-SXR's reference signals in the last shot. The goal of the system is to ensure long-pulse data acquisition and electronics' automatic gain-control. The system has been demonstrated in the 2015 EAST campaign. The details are presented in the paper.

FBGs are promising devices for DWDM networks [1]. Phase mask (PM) technique is one of the most versatile techniques for massive production of FBGs. However, ever increasing requirements of DWDM put stringent requirements on FBG sidelobe suppression and spectral skirt sharpness. In this paper, we report a detailed comparison of different apodization profiles with emphasis on narrow linewidth, sharp spectral skirt and a large figure of merit which is the ratio of bandwidth at -0.5 dB to that at -25 dB. Effective apodized PM was fabricated by using e-beam writing and reactive ion-milling (RIM) with stitching error-free. For a gaussian apodized FBG. it has a gaussian refractive index modulation, an inverse gaussian index background and a constant average index change along the FBG with no unwanted dispersion. FBG apodization using PM dithering technique suffers some drawbacks for pulsed UV excimer lasers and for very high UV photosensitive fibers. Scanning writing apodized FBG technique needs double UV exposures for FBG writing and background index change resulting in a lower control accuracy and a lower fabrication efficiency. Using apodization aperture and amplitude masks have the similar problems of double exposure and lower control accuracy resulting unwanted dispersion. Apodized PM technique is an efficient method for qualified DWDM FBGs production with a simple setup and an excellent fabrication repeatability.

FBGs have been widely used in DWDM devices with a channel spacing of 0.4 nm [1,2]. This requires a high λ accuracy and stability. However, the low temperature coefficient (TC) of 0.011 nm/°C of FBG cannot meet the requirements of DWDMs and other applications. In this paper, a specially designed multi-FBG temperature stabilized package is developed with precise control of center λ and a low TC. Design structure, tuning mechanism, measurement technique, experimental results and reliability of the multi-FBG package are presented.