An equivalent corrugation pitch-modulated （ECPM） distributed feedback （DFB） semiconductor laser with two equivalently assisted phase shifts （EAPS） was theoretically studied and experimentally demonstrated. The s...An equivalent corrugation pitch-modulated （ECPM） distributed feedback （DFB） semiconductor laser with two equivalently assisted phase shifts （EAPS） was theoretically studied and experimentally demonstrated. The simulated results showed that the longitudinal photon density distribution of the ECPM ＋ EAPS DFB lasers was much more uniform than that of a sole ECPM DFB laser without EAPS, and the longitudinal spatial hole burning was therefore suppressed more effectively. The results of experiment showed that good single longitudinal mode operation was achieved, with side mode suppression ratio （SMSR） being over 35 dB, and the wavelength range was from 1,559.64 to 1,563.02 nm when the operation current was from 50 to 160 mA at the temperature of 25 ℃, and the SMSR increased to 46.29 dB when the injection current was 130 mA.展开更多
基金supported by the National Natural Science Foundation of China(61306068 and 61435014)the Natural Science Foundation of Jiangsu Province of China(BK20130585 and BK20140414)+1 种基金the National High Technology Research and Development Program(SS2015AA012302)the Applied Basic Research Project of Suzhou City(SYG201309)
文摘An equivalent corrugation pitch-modulated （ECPM） distributed feedback （DFB） semiconductor laser with two equivalently assisted phase shifts （EAPS） was theoretically studied and experimentally demonstrated. The simulated results showed that the longitudinal photon density distribution of the ECPM ＋ EAPS DFB lasers was much more uniform than that of a sole ECPM DFB laser without EAPS, and the longitudinal spatial hole burning was therefore suppressed more effectively. The results of experiment showed that good single longitudinal mode operation was achieved, with side mode suppression ratio （SMSR） being over 35 dB, and the wavelength range was from 1,559.64 to 1,563.02 nm when the operation current was from 50 to 160 mA at the temperature of 25 ℃, and the SMSR increased to 46.29 dB when the injection current was 130 mA.
文摘为研究大位移井井眼清洁与摩阻扭矩的关系,以及岩屑对当量循环密度(equivalent circulation density,ECD)的影响,利用瞬态岩屑运移模型模拟岩屑在井筒中的瞬态运移过程,并结合实钻井数据分析岩屑对ECD的影响,检验几种常用井眼的经验清洁方法;在实际钻井过程中,考虑到井筒中岩屑的数量和ECD控制要求,提出了大位移井井眼清洁新标准。结果表明:岩屑对ECD的影响随着水平段长度的增加而增加,岩屑对ECD的影响可以通过调节循环频率或机械钻速(rate of penetration,ROP)来控制;从ECD和扭矩-摩阻分析中获得井筒允许的最大岩屑量,综合考虑防止卡阻所需的流速和循环时间这2个因素,并将所得结果作为大位移井井眼清洁的新标准;研究成果还可用于从ECD管理角度确定大位移井裸眼的延伸极限长度。
