A movable-cavity cold atom space clock

We present an experimental scheme of a cold atom space clock with a movable cavity. By using a single microwave cavity, we find that the clock has a significant advantage, i.e. the longitudinal cavity phase shift is eliminated. A theoretical analysis has been carried out in terms of the relation between the atomic transition probability and the velocity of the moving cavity by taking into account the velocity distribution of cold atoms. The requirements for the microwave power and its stability for atomic pi/2 excitation at different moving velocities of the cavity lead to the determination of the proper working parameters of the rubidium clock in frequency accuracy 10(-17). Finally, the mechanical stability for the scheme is analysed and the ways of solving the possible mechanical instability of the device are proposed.

Differential cognitive responses to guqin music and piano music in Chinese subjects: an event-related potential study

目的 研究古琴(一种古老的中国乐器)和钢琴音乐对认知的影响.方法 记录和分析了中国被试在两种音乐背景(古琴音乐,钢琴音乐)下完成听觉oddball任务的行为和事件相关电位(event-related potential,ERP)数据.结果 中国被试在本土文化的音乐环境(古琴音乐)下,前额区诱导出更大的P300,这一结果和已有的相关研究是相符的.同时,不同音乐背景对ERP产生的影响在N1和LPC(包括P300和P500)上也表现出差别:中国被试在古琴音乐背景下比钢琴音乐背景下表现出更多的右前侧颞叶的参与.结论 因为古琴音乐的五声调式和汉语发音的音调具有对应关系,因此我们推断在古琴音乐下所表现出的这种特性与被试的汉语环境有关.

Crossmodal effects of Guqin and piano music on selective attention: An event-related potential study

To compare the effects of music from different cultural environments (Guqin: Chinese music; piano: Western music) on crossmodal selective attention, behavioral and event-related potential (ERP) data in a standard two-stimulus visual oddball task were reco

Crossmodal effects of Guqin and piano music on selective attention: An event-related potential study (vol 466, pg 21, 2009)

Special thanks to Christopher Blair and Mumtaz Baig for their suggestions. This work was supported by National Basic Research Program of China (973 Program, 2007CB411600), National Natural Science Foundation of China (30621092), and Bureau of Science and Technology of Yunnan Province.

All-optical clock recovery using a ridge width varied two-section partly gain-coupled DFB self-pulsation laser

A 1.55 mu m InGaAsP-InP partly gain-coupled two-section DFB self-pulsation laser (SPL) with a varied ridge width has been fabricated. The laser produces self-pulsations with a frequency tuning range of more than 135 GHz. All-optical clock recovery from 40 Gb/s degraded data streams has been demonstrated. Successful lockings of the device at frequencies of 30 GHz, 40 GHz, 50 GHz, and 60 GHz to a 10 GHz sidemode injection are also conducted, which demonstrates the capability of the device for all-optical clock recovery at different frequencies. This flexibility of the device is highly desired for practical uses. Crown Copyright

All-Optical Clock Recovery for 20 Gb/s Using an Amplified Feedback DFB Laser

We report all optical clock recovery based on a monolithic integrated four-section amplified feedback semiconductor laser (AFL), with the different sections integrated based on the quantum well intermixing (QWI) technique. The beat frequency of an AFL is continuously tunable in the range of 19.8-26.3 GHz with an extinction ratio above 8 dB, and the 3-dB linewidth is close to 3 MHz. All-optical clock recovery for 20 Gb/s was demonstrated experimentally using the AFL, with a time jitter of 123.9 fs. Degraded signal clock recovery was also successfully demonstrated using both the dispersion and polarization mode dispersion (PMD) degraded signals separately.

40 Gbits/s all-optical clock recovery for degraded signals using an amplified feedback laser

All-optical clock recovery for the return-to-zero modulation format is demonstrated experimentally at 40 Gbits/s by using an amplified feedback laser. A 40 GHz optical clock with a root-mean-square (rms) timing jitter of 130 fs and a carrier-to-noise ratio of 42 dB is obtained. Also, a 40 GHz optical clock with timing jitter of 137 fs is directly recovered from pseudo-non-return-to-zero signals degraded by polarization-mode dispersion (PMD). No preprocessing stage to enhance the clock tone is used. The rms timing jitter of the recovered clock is investigated for different values of input power and for varying amounts of waveform distortion due to PMD.