| 1. |
- Anand, Srinivasan, et al.
(författare)
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High aspect ratio etching and characterization of 2D-photonic crystals in InP/InGaAsP/InP heterostructures
- 2004
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Ingår i: Photonics. - : SPIE - International Society for Optical Engineering. - 0819451703 ; , s. 78-89
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Konferensbidrag (refereegranskat)abstract
- We report on the fabrication and characterization of 2D photonic crystals (PhCs) in InP/InGaAsP/InP heterostructures. It is demonstrated that Ar/C12 based chemically assisted ion beam etching (CAIBE) is a very promising method to obtain high aspect ratio etching of PhCs in the InP-based materials. With this process, it is possible to obtain PC-holes as deep as 3 microns even for feature (PhC-hole) sizes as small as 200-250 nm. The optical characteristics of the fabricated PhC-based elements/devices such as line-defect waveguides, in-plane resonant cavities and drop-filter based on contra-directional coupling will be reported. The devices were measured using end-fire coupling and the obtained results were simulated using the 2D finite difference time domain (FDTD) method including an effective loss-approximation. The etched PhC-waveguides show low transmission losses, less than 1 dB/100 mum. A quality factor of 400 for a 6 micron long cavity with 6-hole mirrors is obtained. Finally, drop-functionality in a PhC-based filter using contra-directional coupling is demonstrated.
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| 2. |
- Benisty, H., et al.
(författare)
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Models and measurements for the transmission of submicron-width waveguide bends defined in two-dimensional photonic crystals
- 2002
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Ingår i: IEEE Journal of Quantum Electronics. - 0018-9197 .- 1558-1713. ; 38:7, s. 770-785
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Tidskriftsartikel (refereegranskat)abstract
- One of the essential building-blocks of miniature photonic crystal (PC)-based photonic integrated circuits (PICs) is the sharp bend. Our group has focused on the 2-D photonic crystal based on a triangular lattice of holes perforating a standard heterostructure. The latter, GaAlAs-based or InP-based, is vertically a monomode waveguide. We consider essentially one or two 60 bends defined by one to five missing rows, spanning both cases of monomode and multimode channel waveguides. From intensive modeling and various experimental measurements (both on GaAs and InP), we point out the origin of the present level of bend insertion losses and discuss the merits of the many roads open for improved design.
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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. |
- Fernando, Harendra, et al.
(författare)
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Engineering UV-photosensitivity in planar lightwave circuits by plasma enhanced chemical vapour deposition
- 2004
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Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 37:20, s. 2804-2809
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Tidskriftsartikel (refereegranskat)abstract
- Ion bombarding conditions were used to modify glass properties in silica-on-silicon systems during plasma enhanced chemical vapour deposition (PECVD). The induced structural modifications in the SiO2/Si system resulted in different photosensitive responses when irradiated by ArF pulsed laser operating at 193 nm wavelength. Fourier transform infrared spectroscopy was used to study the structural modifications triggered by ion bombarding conditions during film growth. The results were further confirmed by additional characterizations with regard to density (etch rate), refractive index and surface topographic measurements. The demonstrated method could be used not only to engineer UV-photosensitivity but also to control and compensate birefringence in planar lightwave devices.
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| 5. |
- Fernando, H. N. J., et al.
(författare)
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Characterization of ultra-violet-induced changes in planar waveguides
- 2003
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Ingår i: Journal of Optics. A, Pure and applied optics. - : IOP Publishing. - 1464-4258 .- 1741-3567. ; 5:4, s. 335-340
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Tidskriftsartikel (refereegranskat)abstract
- A simple, low-cost spectrophotometer system operating in reflection absorption mode is used to characterize changes in refractive index and thickness of thin films under 193 nm irradiation. The results indicate overall dilation of the glass and are confirmed by additional surface topographic measurements. We also show that in addition to the net relaxation from laser annealing of the interface, in germanosilicate samples local compaction takes place. Since the net relaxation is triggered by remote interactions, it is not spatially confined to the laser-irradiated area. However, a local positive index change is observed. These results are in agreement with previous hypotheses put forward to explain planar waveguide negative index changes. They also bring to attention the great care necessary in both conducting and interpreting measurements that do not take into account spatial variations arising from the combination of remote and local triggers of both index and thickness changes.
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| 6. |
- Jaskorzynska, Bozena, et al.
(författare)
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Active Si-based photonics via heterogeneous integration
- 2008
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Ingår i: ICTON 2008. - NEW YORK : IEEE. - 9781424426256 ; , s. 30-33
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Konferensbidrag (refereegranskat)abstract
- We review major breakthroughs in realizing silicon-based active components by heterogeneous integration with III-V semiconductors, or nonlinear organic materials. In more detail we describe examples of our concepts and technological approach addressing this goal. This includes designs for widely tunable filters and new routes for heteroepitaxy and selective area growth of InP on silicon.
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| 7. |
- Jaskorzynska, Bozena, et al.
(författare)
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Applications of wavelength dispersion in 1D and 2D photonic crystals
- 2005
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE - International Society for Optical Engineering. ; , s. 1-9
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Konferensbidrag (refereegranskat)abstract
- One of the most distinctive features of photonic crystals (PhCs) is their unique wavelength dispersion allowing novel device concepts for enhancement of photonic functionality and performance. Here, we present examples of our design and demonstrations utilizing dispersion properties of 1D and 2D photonic crystals. This includes the demonstration of negative refraction in 2D PhC at optical wavelengths, filters based on 1D and 2D PhC waveguides, and the design of a widely tunable filter involving 1D PhC.
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| 8. |
- Jaskorzynska, Bozena, et al.
(författare)
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Dielectric and Plasmon Slot Waveguides for Photonic Integration
- 2009
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Ingår i: ICTON 2009: 11th International Conference on Transparent Optical Networks. - NEW YORK : IEEE. ; , s. 653-656
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Konferensbidrag (refereegranskat)abstract
- Slot waveguides formed either in high-index dielectrics or in metals attract great interest because they provide sub-wavelength confinement in the slot region. While this feature is very attractive for devices relying on stimulated emission or nonlinear effects, it does not necessarily improve the integration density. The spacing between dielectric slot waveguides is still limited by diffraction. Although for metal (plasmon) waveguides the total field can be shrunk far beyond the diffraction limit, the associated increase in propagation loss will set practical limits on both the minimum waveguide width and edge-to-edge separation. Here we compare the packing densities for 3D slot waveguides in silicon and plasmon waveguides in gold with a silicon slot. As a reference we also consider silicon photonic wire. We calculate center-to-center waveguide separations (pitch) versus cross-talk level. We show that at ca 24 dB/mu m cross-talk and requiring the attenuation length of at least 5 mu m, plasmon slot waveguides can be packed ca 3.5 times denser than silicon slot waveguides, and ca 2.5 times denser than photonic wires. We also show examples of the fabricated devices.
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| 9. |
- Jaskorzynska, Bozena, et al.
(författare)
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Nonlinear upconversion-rate in Er-doped fibers
- 2001
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Ingår i: Acta Physica Polonica. A. - 0587-4246 .- 1898-794X. ; 99:1, s. 147-153
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Tidskriftsartikel (refereegranskat)abstract
- Energy transfer between excited rare-earth ions has been widely used for realizing upconversion lasers and also recognized as a gain limiting factor in high-concentration Er-doped amplifiers. The energy transfer leads to upconversion of the excitation which for randomly distributed (not clustered) ions is called homogeneous upconversion. It was commonly assumed that the rate of homogeneous upconversion is a linear function of the population inversion N-2. However, recently published Monte Carlo simulations predict that the homogeneous upconversion rate is a nonlinear function of N-2 and that it, moreover, depends on the pump and signals rates. In this paper we review some of our experimental results confirming those predictions. We also propose a statistical, analytical model describing the observed homogeneous upconversion behavior in Er-doped fibers.
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| 10. |
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