There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

/pdf/the-observation-of-gravitational-waves-from-a-binary-black-58srpupgg9.pdf

The Observation of Gravitational Waves from a Binary Black Hole Merger

Microwave photonics, which brings together the worlds of radiofrequency engineering and optoelectronics, has attracted great interest from both the research community and the commercial sector over the past 30 years and is set to have a bright future. The technology makes it possible to have functions in microwave systems that are complex or even not directly possible in the radiofrequency domain and also creates new opportunities for telecommunication networks. Here we introduce the technology to the photonics community and summarize recent research and important applications.

Microwave photonics combines two worlds

An overview of analog microwave photonics will be presented. The performance requirements for externally-modulated analog microwave photonic links will be reviewed with specific emphasis placed on modulator efficiency, laser noise, detected photocurrent, and link linearity.

http://ieeexplore.ieee.org/iel5/6387506/6403300/06403360.pdf

Microwave photonics

A method of manufacturing a semiconductor device suitable for optoelectronic switching in response to light of wavelengths in the range 1200 nm to 1600nm, comprising forming an undoped InGaAs layer on an insulative semiconductor substrate and bonded on opposed sides to a pair of electrical contact layers adapted to constitute the electrodes of a switch, comprising forming bulk point defects by irradiating the InGaAs layer with Nitrogen ions.

Semiconductor device for optoelectronic switching

Small-signal experiments with a 2.5 mm-long quantum dot narrow ridge-waveguide laser on silicon show a modulation bandwidth of 1.6 GHz. For the first time, we report key high-speed parameters such as the differential gain and the gain compression factor.

/pdf/dynamic-properties-of-monolithic-1-3-mm-inas-gaas-quantum-33z5a3yd6p.pdf

Dynamic Properties of Monolithic 1.3 μm InAs/GaAs Quantum Dot Lasers on Silicon

We were interested to read the above short paper, but would like to point out that experimental results on the optical injection locking of IMPATT oscillators have indeed been obtained. Over the last few years, reports of such experiments have appeared in the literature from groups in both Europe and the U.S.A.

Optical Injection Locking of BARITT Oscillators (Comments)

Passive MQW saturable absorbers and narrow-band filters permit 100km optical amplifier spacings in a proposed soliton system. After 9000km at 10Gbit/s, soliton-soliton interactions and Gordon-Haus jitter yield BER better than 10.

Increased amplifier spacing using quantum well saturable absorbers and spectral filtering in a soliton system

Bi-Directional Transmission of Broadband 5.2 GHz Wirless Signals Over Fibre Using a Multiple-Quantum-Well Asymmetric Fabry-Perot Modulator/Photodetector

Alwyn J. Seeds

Papers

Semiconductor device for optoelectronic switching

Dynamic Properties of Monolithic 1.3 μm InAs/GaAs Quantum Dot Lasers on Silicon

Optical Injection Locking of BARITT Oscillators (Comments)

Increased amplifier spacing using quantum well saturable absorbers and spectral filtering in a soliton system

Bi-Directional Transmission of Broadband 5.2 GHz Wirless Signals Over Fibre Using a Multiple-Quantum-Well Asymmetric Fabry-Perot Modulator/Photodetector