High slope efficiency and low noise characteristics in tapered-active-stripe DFB lasers with narrow beam divergence

1999 ◽  
Vol 35 (12) ◽  
pp. 1765-1770 ◽  
Author(s):  
M. Kito ◽  
Y. Inaba ◽  
H. Nakayama ◽  
T. Chino ◽  
M. Ishino ◽  
...  
Keyword(s):  
Slope Efficiency ◽  
Low Noise ◽  
Beam Divergence ◽  
Narrow Beam ◽  
High Slope ◽  
Noise Characteristics ◽  
Active Stripe

scholarly journals A Four-Channel Low-Noise Readout IC for Air Flow Measurement Using Hot Wire Anemometer in 0.18 μm CMOS Technology

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4694
Author(s):  
Kyeongsik Nam ◽  
Hyungseup Kim ◽  
Yongsu Kwon ◽  
Gyuri Choi ◽  
Taeyup Kim ◽  
...  
Keyword(s):  
Supply Voltage ◽  
Air Flow ◽  
Low Noise ◽  
Cmos Process ◽  
Significant Information ◽  
Flow Measurements ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Op Amp ◽  
Noise Characteristics

Air flow measurements provide significant information required for understanding the characteristics of insect movement. This study proposes a four-channel low-noise readout integrated circuit (IC) in order to measure air flow (air velocity), which can be beneficial to insect biomimetic robot systems that have been studied recently. Instrumentation amplifiers (IAs) with low-noise characteristics in readout ICs are essential because the air flow of an insect’s movement, which is electrically converted using a microelectromechanical systems (MEMS) sensor, generally produces a small signal. The fundamental architecture employed in the readout IC is a three op amp IA, and it accomplishes low-noise characteristics by chopping. Moreover, the readout IC has a four-channel input structure and implements an automatic offset calibration loop (AOCL) for input offset correction. The AOCL based on the binary search logic adjusts the output offset by controlling the input voltage bias generated by the R-2R digital-to-analog converter (DAC). The electrically converted air flow signal is amplified using a three op amp IA, which is passed through a low-pass filter (LPF) for ripple rejection that is generated by chopping, and converted to a digital code by a 12-bit successive approximation register (SAR) analog-to-digital converter (ADC). Furthermore, the readout IC contains a low-dropout (LDO) regulator that enables the supply voltage to drive digital circuits, and a serial peripheral interface (SPI) for digital communication. The readout IC is designed with a 0.18 μm CMOS process and the current consumption is 1.886 mA at 3.3 V supply voltage. The IC has an active area of 6.78 mm2 and input-referred noise (IRN) characteristics of 95.4 nV/√Hz at 1 Hz.

980 nm high power, high slope efficiency distributed feedback lasers with nonabsorbing mirrors

1998 ◽  
Vol 34 (17) ◽  
pp. 1663 ◽  
Author(s):  
R.M. Lammert ◽  
J.E. Ungar ◽  
S.W. Oh ◽  
H. Qi ◽  
J.S. Chen ◽  
...  
Keyword(s):  
High Power ◽  
Slope Efficiency ◽  
Distributed Feedback ◽  
Distributed Feedback Lasers ◽  
High Slope

The multi-functional rotor aerodynamic and aeroacoustic test platform at HKUST

2021 ◽  
Vol 263 (2) ◽  
pp. 4410-4417
Author(s):  
Han Wu ◽  
Chuntai Zheng ◽  
Peng Zhou ◽  
Ryu Fattah ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Phase Locking ◽  
Axial Flow ◽  
Low Noise ◽  
Test Rig ◽  
Tunnel Wall ◽  
Noise Characteristics ◽  
Piv Measurement ◽  
Test Platform ◽  
Semi Empirical

This paper describes the multi-functional rotor noise and aerodynamics test platform at the Hong Kong University of Science and Technology (HKUST). To investigate the noise characteristics of propellers with aerodynamic flows, the test rig is installed in the 2.5×2 (m) low-speed and low-noise wind tunnel in the Aerodynamic and Acoustic Facility (AAF) at HKUST. The wind tunnel can facilitate flow from 0 to 40 m/s. The test rig is assembled in a turntable on the ceiling of the tunnel wall, which enables the testing range of pitch angle can vary from 0° (axial flow) to 90° (parallel flow), with an accuracy of 0.1°. The noise produced by the rotor is measured by a set of wall-mounted surface microphones. Semi-empirical calibration is conducted to quantify the noise reflection by the tunnel walls. A low-noise struct has been designed and manufactured to locate a set of far-field microphones equipped with nosecone, to improve the quality of acoustic measurement inside the flow. In addition, a synchronized system is developed to conduct the phase-locking Particle Image Velocimetry (PIV) measurement on the rotor, to study the flow pattern to better understand the noise generation mechanism.

scholarly journals Wide-field Astronomy with Tech Pan Film - A Positive Outlook for Schmidt Photography

1995 ◽  
Vol 148 ◽  
pp. 96-103 ◽  
Author(s):  
Quentin A Parker ◽  
Steven Phillipps ◽  
David Morgan
Keyword(s):  
Economic Benefits ◽  
Low Noise ◽  
Area Coverage ◽  
Wide Field ◽  
Medium Term ◽  
Significant Information ◽  
Field Surveys ◽  
Noise Characteristics ◽  
Co Addition ◽  
Positive Outlook

AbstractThe introduction of film-based Kodak Technical Pan emulsion at the UKST has led to a new lease of life for deep, wide-field astrophotography. This is because the excellent imaging, resolution and low noise characteristics of Tech Pan typically yield a one magnitude depth gain over equivalent IIIa-F plates. Many new projects are underway to take advantage of the significant information gains. The cheap cost of film and ease of transportation gives direct economic benefits too. Tech Pan could also offer a medium term, competitive alternative to CCD mosaics for providing new, deep, wide-field surveys via stacking of several digitised exposures of the same field. A one magnitude gain could result from the stacking of just 6 Tech Pan films to yield an R ∼ 23.5–24. Even without digital co-addition the largest current CCDs cannot hope to match Tech Pan’s inherent ∼ 3 µm resolution and the 40 square degree area coverage of the UKST.

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