Metal alloy and monoelemental nanoclusters in silica formed by sequential ion implantation and annealing in selected atmosphere

The preparation of metal alloy and monoelemental nanoclusters in silica by Ag, Cu ion sequential implantation and annealing in selected oxidizing or reducing atmosphere is studied. The formation of metastable Ag-Cu alloy is verified in the as-implanted samples by optical absorption spectra, selected area electron diffraction and energy dispersive spectrometer spectrum. The alloy is discomposed at elevated annealing temperature in both oxidizing and reducing atmospheres. The different effects of annealing behaviors on the Ag Cu alloy nanoclusters are investigated. (C) 2004 Elsevier B.V. All rights reserved.

Excitonic photoluminescence properties of nanocrystalline GaSb and Ga0.62In0.38Sb embedded in silica films

The GaSb and Ga0.62In0.38Sb nanocrystals were embedded in the SiO2 films by radio-frequency magnetron co-sputtering and were grown on GaSb and Si substrates at different temperatures. We present results on the 10K excitonic photoluminescence (PL) properties of nanocrystalline GaSb and Ga0.62In0.38Sb as a function of their size. The measurements show that the PL of the GaSb and Ga0.62In0.38Sb nanocrystallites follows the quantum confinement model very closely. By using deconvolution of PL spectra, origins of structures in PL were identified. (C) 2002 Elsevier Science B.V. All rights reserved.

Improved purity of long-wavelength InAsSb epilayers grown by melt epitaxy in fused silica boats

In this study, we first present the process of the melt epitaxial (ME) growth method, and the improvement of low-temperature electron mobility of the long-wavelength InAsSb epilayers grown by ME in a fused silica boat. The electrical properties were investigated by van der Pauw measurement at 300 and 77 K. It is seen that the electron mobility of the InAsSb samples grown by graphite boat decreased from 55,700 to 26,600 cm(2)/V s when the temperature was reduced from 300 to 77 K, while for the samples grown by fused silica boat, the electron mobility increased from 52,600 at 300 K to 54,400 cm(2)/V s at 77 K. The electron mobility of 54,400cm(2)/Vs is the best result, so far, for the InAsSb materials with cutoff wavelength of 8-12 mum at 77 K. This may be attributed to the reduction of the carbon contamination by using a fused silica boat instead of a graphite boat. (C) 2002 Elsevier Science B.V. All rights reserved.

Fabrication of a novel silica PLC hybrid integrated triplexer

A new-style silica planar lightwave circuit (PLC) hybrid integrated triplexer, which can demultiplex 1490-nm download data and 1550-nm download analog signals, as well as transmit 1310-nm upload data, is presented. It combines SiO2 arrayed waveguide gratings (AWGs) with integrated photodetectors (PDs) and a high performance laser diode (LD). The SiO2 AWGs realize the three-wavelength coarse wavelength-division multiplexing (CWDM). The crosstalk is less than 40 dB between the 1490- and 1550-nm channels, and less than 45 dB between 1310- and 1490- or 1550-nm channels. For the static performances of the integrated triplexer, its upload output power is 0.4 mW, and the download output photo-generated current is 76 A. In the small-signal measurement, the upstream 3-dB bandwidth of the triplexer is 4 GHz, while the downstream 3-dB bandwidths of both the analog and digital sections reach 1.9 GHz.

Optical responses of ZnSe quantum dots in silica gel glasses

The characteristic features of the absorption and photoluminescence spectra of ZnSe quantum dots (QDs) inside a silica matrix derived from a sol-gel method were studied at room temperature. Compared with the bulk materials, the absorption edges of ZnSe QDs in silica gel glass were shifted to higher energies and the spectra exhibited the discrete excitonic features due to the quantum confinement effects. Besides the band-edge emission, photoluminescence at ultraviolet excitation also showed the emissions related to the higher excitonic states. (C) 2004 Elsevier B.V. All rights reserved.

Micro Fabry-Perot interferometers in silica fibers machined by femtosecond laser

Micro Fabry-Perot (F-P) interferometers (MFPIs) are machined in a single-mode fiber (SMF) and a photonic crystal fiber (PCF) by using a near-infrared femtosecond laser, respectively. The strain and temperature characteristics of the two MFPIs with an identical cavity length are investigated and the experimental results show that the strain sensitivity of the PCF-based MFPI is smaller than that of the SMF-based MFPI due to their different waveguide structures, while the two MFPIs have close temperature sensitivities which are much smaller than that of an in-line SMF etalon sensor reported previously. These MFPIs in silica fibers are compact, stable, inexpensive, capable for mass-production and easy fabrication, offering great potentials for wide sensing applications. (c) 2007 Optical Society of America.

基于silica波导光栅的单纤三向器的混合集成研究

通过有源实时监控系统,采用手动和自动相结合的方法,将光纤、silica基阵列波导光栅(AWG)、1310 nm激光器(LD)平台和1490 nm、1550 nm探测器(PD)平台用紫外同化胶混合集成为一新型单纤三向器.在耦合集成过程中,LD在15 mA偏置电流下,三向器的上行出纤功率大约为-4 dBm,LD和波导的耦合效率大约40%;当三向器输入1 550 nm光功率为1 mW,PD在2.6 V反向偏压下,下行输出光电流大约为76 μA,波导和PD的耦合效率大约为42%.三向器中采用了对管PD集成方法.

Design and numerical analysis for low birefringence silica on silicon waveguides

A new fabrication technology for three-dimensionally buried silica on silicon optical waveguide based on deep etching and thermal oxidation is presented. Using this method, a silicon layer is left at the side of waveguide. The stress distribution and effective refractive index are calculated by using finite element method and finite different beam propagation method, respectively. The results indicate that the stress of silica on silicon optical waveguide fabricated by this method can be matched in parallel and vertical directions and stress birefringence can be effectively reduced due to the side-silicon layer.