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| 2. |
- Dainese, Matteo, et al.
(författare)
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Influence of Ge content on the optical quality of Plasma CVD deposited Silica films
- 2002
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Konferensbidrag (refereegranskat)abstract
- The feasibility of a full low temperature process, based on Plasma Enhanced Chemical VaporDeposition, for the fabrication of low loss silica-based optical waveguides is investigated.Results from XPS, FTIR, ERDA, isochronal wet etch rate, prism coupler measurements showthat (low frequency) RF power is a critical parameter to improve microstructural properties ofas-deposited SiO2 and minimize Rayleigh scattering. Ge doping of the silica matrix in thecore layer increases network disorder and point defects density, mainly due to the highlyreactive characteristics of the employed gas precursor (germane) and the high stickingcoefficients of its radicals. Measurements on fabricated optical waveguides show that forrelative refractive index differences between core and cladding up to 0.75%, the opticallosses are acceptable for the fabrication of high performance devices.
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| 3. |
- Dainese, Matteo, et al.
(författare)
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Narrow band coupler based on one-dimensional Bragg reflection waveguide
- 2003
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Ingår i: 2003 Optical Fiber Communication Conference. - 1557527466 ; , s. 44-46
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Konferensbidrag (refereegranskat)abstract
- A new configuration based on the coupling between a conventional low loss, weakly guiding channel waveguide and a Bragg reflection waveguide (BRW) was discussed. The strong difference between the dispersion of a Bragg reflection waveguide and a channel waveguide was used to create a narrow band coupler. The two-dimensional analysis of the BRW was generally based on the transfer matrix method. The structure consisted of a weakly guiding conventional Ge-doped silica waveguide on the top of which a BRW was stacked. The number of periods in the mirror between the BRW and the silica waveguide affected the coupling length and ultimately the bandwidth.
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| 4. |
- Dainese, Matteo, et al.
(författare)
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Photosensitivity of boron-codoped PECVD films in application to grating assisted WDM devices
- 2004
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Ingår i: INTEGRATED OPTICS AND PHOTONIC INTEGRATED CIRCUITS. - BELLINGHAM : SPIE-INT SOC OPTICAL ENGINEERING. - 0819453749 ; , s. 191-198
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Konferensbidrag (refereegranskat)abstract
- UV sensitivity of B-Ge codoped cores in PECVD silica waveguides has been investigated. Photoinduced refractive index changes have been introduced by KrF excimer laser irradiation at 248 rim, without any presensitization method. The effects of B codoping of Ge doped silica have been examined. It has been shown that B addition mildly increases glass network disorder, by broadening the O bridging angle distribution as from FTIR measurements, but on the other hand it does not produce point defects which may contribute to the absorption band at 5eV already generated by the presence of Ge doping. The fabricated channel waveguides show low optical loss even without high temperature annealing. Strong Bragg gratings imprinted into these waveguides confirm that in non thermally annealed Ge doped PECVD silica glass, where a small absorption band still exist at 5eV, B codoping supplies sufficient photosensitivity amplification to make hydrogen loading unnecessary.
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| 5. |
- Niklaus, Frank, et al.
(författare)
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Characterization of transfer bonded silicon bolometer arrays
- 2004
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Ingår i: INFRARED TECHNOLOGY AND APPLICATIONS XXX. - BELLINGHAM : SPIE-INT SOC OPTICAL ENGINEERING. - 0819453293 ; , s. 521-530
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Konferensbidrag (refereegranskat)abstract
- In this paper we present the design, fabrication and characterization of arrays of boron doped polycryslalline silicon bolometers, The bolometer arrays have been fabricated using CMOS compatible wafer-level transfer bonding. The transfer bonding technique allows the bolometer materials to be deposited and optimized on a separate substrate and then, in a subsequent integration step to be transferred to the read-out integrated circuit (ROIC) wafer. Transfer bonding allows thermal infrared detectors with crystalline and/or high temperature deposited, high performance temperature sensing materials to be integrated on CMOS based ROICs. Uncooled infrared bolometer arrays with 18x18 pixels and with 320x240 pixels have been fabricated on silicon substrates. Individual pixels of the arrays can be addressed for characterization purposes. The resistance of the bolometers has been measured to be in the 50 kOmega range and the temperature coefficient of resistance (TCR) of the bolometer has been measured to be -0.52 %/K. The pixel structure is designed as a resonant absorbing cavity, with expected absorbance above 90%, in the wavelength interval of 8 to 12 mum. The measured results are in good agreement with the predicted absorbance values.
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| 6. |
- Symonds, Clémentine, et al.
(författare)
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High performance 1.55μm vertical external cavity surface emitting laser with broadband integrated dielectric-metal mirror
- 2004
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 40:12, s. 734-735
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Tidskriftsartikel (refereegranskat)abstract
- 1.55 μm room-temperature continuous-wave operation of a high performance optically pumped vertical external cavity surface emitting laser is reported. The structure includes an active region with strain compensated quantum wells, and a broadband SiNx/Si/Au Bragg reflector transferred on an Si substrate by Au/In dry bonding. Output power of up to 45 mW is achieved at 0°C, and continuous-wave operation is observed up to 45°C.
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| 7. |
- Wosinski, Lech, et al.
(författare)
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Grating-assisted add-drop multiplexer realized in silica-on-silicon technology
- 2003
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Ingår i: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 4941, s. 43-50
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Tidskriftsartikel (refereegranskat)abstract
- Silica-on-Silicon is a well established technology for the fabrication of low insertion loss planar lightwave circuits. The Ge-doped waveguide core material, deposited with low temperature plasma enhanced chemical vapor deposition and not subjected to high temperature annealing, is highly UV light photosensitive, due to residual Ge/Si-OH groups in the material that, similarly to hydrogen loading, can contribute to the formation of those defect centers responsible for the photosensitivity. Gratings have been-fabricated using a pulsed 193 nm ArF excimer laser and a phase mask. 25 mm long gratings, written on standard straight waveguides, show a record 47 dB extinction ratio and 0.2 nm rejection bandwidth for TE polarization, without hydrogen loading. Such narrow linewidth filters could find application in dense WDM systems. We designed and fabricated a compact Add/Drop multiplexer based on a high bandwidth, 2x2 multimode interference device, having a Bragg grating written in the multi-mode region. The characterisation for the TE polarisation prove the proposed Add/Drop principle, showing, in correspondence of the dropped channel, a 30dB dip at the transmitted output and a reflection peak at the drop output, this last having a larger bandwidth, and around 3dB excess loss respect to the transmitted channels.
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| 8. |
- Wosinski, Lech, et al.
(författare)
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Material consideration for integrated optics in silica-on-silicon technology
- 2003
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Ingår i: Proceedings volumes / Electrochemical society. - 0161-6374. ; 1, s. 130-144
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we present guidelines for optimization of process parameters for low temperature deposition of silica films for optical applications. The fabrication of optical integrated circuits based on silica deposition on silicon substrates with plasma enhanced CVD introduces different challenges in this technology, with respect to its traditional application in the field of microelectronics. The thick layers required, make deposition rate a very important parameter of merit. High accuracy of this thickness and refractive index as well as their uniformity over large area of the wafer are also very important for the functionality of the fabricated devices. Finally low processing temperature is essential as it allows monolithic integration with temperature sensitive semiconductor components. In this study a commercial parallel plate reactor has been used and the deposition parameters have been analysed to determine the process window, which allows fulfilling all these demands, so as to make a subsequent high temperature consolidation step not necessary.
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| 9. |
- Wosinski, Lech, et al.
(författare)
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PECVD technology for low temperature fabrication of silica-on-silicon based channel waveguides and devices
- 2000
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Ingår i: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 4087, s. 503-507
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Tidskriftsartikel (refereegranskat)abstract
- Silicabased planar technology on silicon has been identified as avery serious source of devices for optical communications:ystems. Low temperaturefabrication of passive and active structures is of special interestas it allows monolithicintegration with temperature sensitive semiconductor components ona common silicon platform.Standard PEC\'D (Plasma Enhanced Chemical Vapour Deposition)processing for fabrication of silica based opticalwaveguides has been investigatedto optimize the process parameters. We chose a high powerprocess regime with highratio between nitrous oxide and silane gasflows as the best conditions. Significant improvement in optical propertiesofsilica-on-silicon planar waveguides for optical communication in the 1.50 -1.55 tmwavelength range has been obtained.
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