Monolithic integration of electroabsorption modulators and tunnel injection distributed feedback lasers using quantum well intermixing

Electroabsorption modulators combining Franz-Keldysh effect and quantum confined Stark effect have been mono-lithically integrated with tunnel-injection quantum-well distributed feedback lasers using a quantum well intermixing method. Superior characteristics such as extinction ratio and temperature insensitivity have been demonstrated at wide temperature ranges.

Simplified modeling of frequency behavior in photonic crystal vertical cavity surface emitting laser with tunnel injection quantum dot in active region

In this work, the characteristics of the photonic crystal tunneling injection quantum dot vertical cavity surface emitting lasers（Ph C-TIQD-VCSEL） are studied through analyzing a modified modulation transfer function. The function is based on the rate equations describing the carrier dynamics at different energy levels of dot and injector well. Although the frequency modulation response component associated with carrier dynamics in wetting layer（WL） and at excited state（ES） levels of dots limits the total bandwidth in conventional QD-VCSEL, our study shows that it can be compensated for by electron tunneling from the injector well into the dot in TIQD structure. Carrier back tunneling time is one of the most important parameters, and by increment of that, the bias current dependence of the total bandwidth will be insignificant. It is proved that at high bias current, the limitation of the WL-ES level plays an important role in reducing the total bandwidth and results in rollovers on 3-d B bandwidth-I curves. In such a way, for smaller air hole diameter of photonic crystal, the effect of this reduction is stronger.

The application of ultrasonic seismic model experiment in quality test of cement mortar injection of Yongjiang river submarine tun－nel tube foundation

Ultrasonic seismic model experiment plays an important role in engineering multi wave seismic prospecting(EMSP), which has been used to do the complex engineering seismic exploration. It is introduced that the application of the technology in quality test of Yongjiang river submarine tunnel tube foundation in the paper. The material of the model was got from on the spot. The successful test has been made with results of the model experiment.

Application study on complex wetting agent for dust-proof after gas drainage by outburst seams in coal mines

After gas drainage, the outburst seam is dry and, consequently, during subsequent mechanized mining, unwanted dust production is extensive. Because the hard dustfall typically has a small particle size it contains a high percentage of respirable dust. Considering these factors, this paper improved the efficiency of dustfall by reducing the surface tension of the liquid used as a wetting agent, then configuring five kinds of wetting agents by adopting various doses and types of surfactants, neutral inorganic salts and chemical additives, etc. After purchasing DA-85 and SRJ-1 wetting agent, the surface tension and critical micelle concentration of seven kinds of wetting agents were measured using the capillary rise method. Wetting agent A was confirmed to have the best comprehensive effect. The experiments were optimized by measuring and comparatively analyzing contact angles of pure water, SRJ-1 wetting agent and wetting agent A on the surface of different coal samples using a contact angle measurement instrument （HARKE- SPCA）. By comparative analysis, dust-proof effects of seam, dynamic pressure water infusion and high- pressure spray in the tunneling face at the Daning coal mine using pure water, wetting agent SRJ-1 and A, it was determined that after using wetting agent A, the average dust concentration in the place of the mining machine driver, 10 m and 110 m away from the tunneling front is approximately 300 rag/ m^3, 240 mg/m^3 and 100 mg/m^3, respectively, This practice increased the dust-proof efficiency dramati- cally and achieved a good comprehensive dust-proof effect.

Photomultiplication type all-polymer photodetectors with single carrier transport property

Photomultiplication(PM)type all-polymer photodetectors(all-PPDs)are first demonstrated with the sandwich structure of ITO/PEDOT:PSS/PBDB-T:PZ1(100:x,wt/wt)/Al.The optimal PM type all-PPDs with PBDB-T:PZ1(100:3,wt/wt)as active layers exhibit external quantum efficiency(EQE)of>100%in the spectral range from 310 to 790 nm.Under 675 nm light illumination,the champion EQE value arrives to 1,470%at-20 V bias and the specific detectivity approaches 1×10^12 Jones at-10 V bias.The PM phenomenon in all-PPDs results from hole tunneling injection assisted by interfacial band bending induced by trapped electrons in PZ1 near Al electrode.The EQE values of optimal PM type all-PPDs still remained over 90%of the original value after 60 d of the storage in a high-purity nitrogen-filled glove box.