Low-timing-jitter, stretched-pulse passively mode-locked fiber laser with tunable repetition rate and high operation stability

We design a low-timing-jitter, repetition-rate-tunable, stretched-pulse passively mode-locked fiber laser by using a nonlinear amplifying loop mirror (NALM), a semiconductor saturable absorber mirror (SESAM), and a tunable optical delay line in the laser configuration. Low-timing-jitter optical pulses are stably produced when a SESAM and a 0.16 m dispersion compensation fiber are employed in the laser cavity. By inserting a tunable optical delay line between NALM and SESAM, the variable repetition-rate operation of a self-starting, passively mode-locked fiber laser is successfully demonstrated over a range from 49.65 to 50.47 MHz. The experimental results show that the newly designed fiber laser can maintain the mode locking at the pumping power of 160 mW to stably generate periodic optical pulses with width less than 170 fs and timing jitter lower than 75 fs in the 1.55 mu m wavelength region, when the fundamental repetition rate of the laser is continuously tuned between 49.65 and 50.47 MHz. Moreover, this fiber laser has a feature of turn-key operation with high repeatability of its fundamental repetition rate in practice.

Atmospheric cu and pb deposition and transport in lake sediments in a remote mountain area；northern China

IEECAS SKLLQG

HIRFL—CSR循环冷却水温度远程测量系统设计；A Design of Remote Temperature-measuring System for HIFRL-CSR Recyclable Cooling Water System

介绍了一种基于一线总线数字温度传感器的HIFRL-CSR循环冷却水温度远程测量系统,阐述了以DT400模块为核心的温度测量的硬件模块和软件设计。该系统具有测温精度高、易扩展性、低成本、低功耗、可靠性高、抗干扰能力强等特点,根据不同需要可应用于多种温度测量系统中。