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.

THE EFFECT OF PASSIVATION OF BORON DOPANTS BY HYDROGEN IN NANO-CRYSTALLINE AND MICROCRYSTALLINE SILICON FILMS

It is well known that the value of room-temperature conductivity sigma(RT) of boron-doped silicon films is one order lower than that of phosphorus-doped silicon films, when they are deposited in an identical plasma-enhanced chemical vapour deposition system. We use surface acoustic wave and secondary-ion mass spectrometry techniques to measure the concentration of total and electrically active boron atoms. It is shown that only 0.7% of the total amount of incorporated boron is electrically active. This is evidence that hydrogen atoms can passivate substitutional B-Si bonds by forming the neutral B-H-Si complex. By irradiating the boron-doped samples with a low-energy electron beam, the neutral B-H-Si complex converts into electrically active B-Si bonds and the conductivity can be increased by about one order of magnitude, up to the same level as that of phosphorus-doped samples.

REDUCTION OF CRYSTALLINE DISORDER IN MOLECULAR-BEAM EPITAXY GAAS ON SI BY MEV ION-IMPLANTATION AND SUBSEQUENT ANNEALING

Molecular beam epitaxy GaAs films on Si, with thicknesses ranging from 0.9-2.0-mu-m, were implanted with Si ions at 1.2-2.6 MeV to doses in the range 10(15)-10(16) cm-2. Subsequent rapid infrared thermal annealing was carried out at 850-degrees-C for 15 s in a flowing N2 atmosphere. Crystalline quality was analyzed by using Rutherfold backscattering/channeling technique and Raman scattering spectrometry. The experimental results show that the recrystallization process greatly depends on the dose and energy of implanted ions. Complete recrystallization with better crystalline quality can be obtained under proper implantation and subsequent annealing. In the improved layer the defect density was much lower than in the as-grown layer, especially near the interface.

SPECTROSCOPIC INVESTIGATION OF HYDROGEN-DOPANT COMPLEXES IN BULK P-TYPE AND IMPLANTED N-TYPE CRYSTALLINE SILICON

Infrared absorption experiments have been performed on hydrogenated and deuterated bulk boron- and aluminum-doped-Si and implanted P, As, and Sb donors in silicon. A first evidence of complex formation in bulk p-type Si is obtained and the spectra confirm the anomalous 3.3-cm-1 deuterium frequency shift with respect to boron isotopes. The ratio of the D-B-11 and D-B-10 peak areas is found to be the same as that of the two boron isotopes natural abundance. In donor-implanted silicon, a quantitative analysis of the obtained data has allowed a rough estimate of the passivating rate due to diffusing deuterium. While the frequencies of the various vibrational lines are found to be in agreement with those reported in the literature, the data on the broad line at 1660 cm-1 (H) or 1220 cm-1 (D) seem to suggest an assignment of this peak to a complex in the bulk involving some type of defect due to the implantation process.

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.