High stability laser source for Taiji-1 satellite

2021 ◽  
pp. 2140006
Author(s):  
Guang-Wei Sun ◽  
Di-Jun Chen ◽  
Guo-Feng Xin ◽  
Hai-Wen Cai ◽  
Wei-Biao Chen ◽  
...  
Keyword(s):  
Temperature Control ◽  
High Stability ◽  
Current Control ◽  
Ring Oscillator ◽  
Laser Source ◽  
Frequency Noise ◽  
Driving Current ◽  
Ground Test ◽  
Power Noise ◽  
Solid Laser

A high stability Laser source at 1064 nm for Taiji-1 satellite is reported. The key component of the Laser source is a nonplanar ring oscillator (NPRO) solid laser with linewidth of 260 Hz. Frequency noise and power noise of Laser source are greatly improved by applying precision driving current control and temperature control. The frequency noise of 0.1 MHz/sqrt(Hz)@ 0.1 Hz and the power noise of 0.02%@0.1 Hz are obtained. Its working performances in-orbit are analyzed and compared with the ground test, showing negligible variation.

Field oriented predictive control strategy for induction machine drives

2017 ◽  
Vol 37 (1) ◽  
pp. 103-113 ◽  
Author(s):  
Xin Qi ◽  
Lin Wu ◽  
Xiaomin Zhou ◽  
Xianghua Ma
Keyword(s):  
Predictive Control ◽  
Control Strategy ◽  
Induction Machine ◽  
Sampling Frequency ◽  
Current Control ◽  
Switching Frequency ◽  
Frequency Noise ◽  
Boundary Circle ◽  
Content Type ◽  
Simulation Step

Purpose This study aims to drive the induction machine system with a low switching frequency. Design/methodology/approach An unconventional inverter control strategy – field-oriented predictive control (FOPC) – is presented. The strategy limits current distortion by setting a boundary circle. The voltage vector, which could keep current trajectories in boundary, is selected to obtain a low switching frequency. Findings A dual simulation step technique is developed to investigate the influence of sampling frequency on current distortion control and switching frequency. Current control distortion can be improved, i.e. reduced, by increasing the sampling frequency; however, the switching frequency will also increase. Such a law is discovered by the dual simulation step technique and finally verified by experiments. Originality/value A new predictive control method, FOPC, is derived from the rotor filed coordinate machine model and presented in this paper. FOPC circumvents derivative calculations, and thus avoids high-frequency noise amplification.

Analysis, Selection and Control of Optimal Driving Current Combinations in Wavelength Switching for DBR Lasers

2013 ◽  
Vol 284-287 ◽  
pp. 2593-2597
Author(s):  
Hsien Wei Tseng ◽  
Yang Han Lee ◽  
Chih Yuan Lo ◽  
Chao Chung Huang ◽  
Ming Hsueh Chuang ◽  
...  
Keyword(s):  
Control Method ◽  
Switching Time ◽  
Current Control ◽  
Bragg Reflector ◽  
System Structure ◽  
Distributed Bragg Reflector ◽  
International Telecommunication Union ◽  
International Telecommunication ◽  
Driving Current ◽  
And Control

In this paper we exploit a basic type of three-stage Distributed Bragg Reflector (DBR) laser that by adjusting its input driving currents in the tri-electrode to generate signals with wavelengths that are in the International Telecommunication Union (ITU)-Band. Many driving current combinations can generate the same ITU wavelength; we will consider in this paper the situation when the input currents are restricted within certain range and to find for all those input current combinations that generate output signals with wavelengths locating in the ITU defined wavelength range. And we will through simulations to determine which set of current combinations will generate the shortest switching time. We will also propose a new current control method, when we know in advance the signal will be switched to certain band, to determine the best current switching combinations that resulting in faster and shorter switching time than that of the conventional system structure which has the drawback that it has only one fixed current combinations for each channel.

scholarly journals High stability, fast tunable single frequency laser source for space based lidar applications

2017 ◽  
Author(s):  
Klaus Schieber ◽  
Thomas Schwander ◽  
Robert Lange ◽  
Berry Smutny ◽  
Frank Heine ◽  
...  
Keyword(s):  
High Stability ◽  
Single Frequency ◽  
Laser Source ◽  
Frequency Laser

110 W high stability green laser using type II phase matching KTiOPO4 (KTP) crystal with boundary temperature control

2005 ◽  
Vol 245 (1-6) ◽  
pp. 341-347 ◽  
Author(s):  
De-Gang Xu ◽  
Jian-Quan Yao ◽  
Bai-Gang Zhang ◽  
Rui Zhou ◽  
Enbang Li ◽  
...  
Keyword(s):  
Temperature Control ◽  
High Stability ◽  
Green Laser ◽  
Phase Matching ◽  
Type Ii ◽  
Boundary Temperature ◽  
Ktp Crystal

Frequency Noise Reduction of Integrated Laser Source with On-Chip Optical Feedback

2017 ◽  
Author(s):  
Bowen Song ◽  
Keisuke Kojima ◽  
Sergio Pinna ◽  
Toshiaki Koike-Akino ◽  
Bingnan Wang ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Optical Feedback ◽  
Laser Source ◽  
Frequency Noise ◽  
On Chip

High Stability of Temperature Control Using Vacuum Insulated Wall for Gauge Block Measurement

2014 ◽  
Vol 613 ◽  
pp. 133-138 ◽  
Author(s):  
Monludee Ranusawud ◽  
Pichet Limsuwan ◽  
Ketsaya Vatcharanukul ◽  
Thammarat Somthong
Keyword(s):  
Heat Transfer ◽  
Temperature Control ◽  
Measurement System ◽  
Heat Conductivity ◽  
High Stability ◽  
Temperature Stability ◽  
Rotary Pump ◽  
Gauge Block ◽  
Critical Effect ◽  
Aluminum Plates

The temperature has a critical effect on long gauge block measurement by interferometry. To reduce this effect, we developed a vacuum insulated wall for long gauge block measurement system. The long gauge block chamber has the dimension of 1.2 m x 2 m. The vacuum insulating walls are mainly composed of 8-mm and 10-mm thick Aluminum plates as the chamber walls and a rotary pump. Using this technique, the vacuum insulator is treated to have the pressure of 0.9 mbar. This technique can reduce heat transfer from outside environment to the chamber due to low heat conductivity of the system. The temperature stability of the chamber had been continuously investigated using 5 Pt100 probes and their temperature stability are below 15 mK at 17 OC, 20 OC and 23 OC

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