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- Benisty, H., et al.
(författare)
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Low-loss photonic-crystal and monolithic InP integration : Bands, bends, lasers, filters
- 2004
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Ingår i: Photonic Crystal Materials and Devices II. - : SPIE - International Society for Optical Engineering. - 0819452688 ; , s. 119-128
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Konferensbidrag (refereegranskat)abstract
- Practical realizations of 2D (planar) photonics crystal (PhC) are either on a membrane or etched through a conventional heterostructure. While fascinating objects can emerge from the first approach, only the latter approach lends itself to a progressive integration of more compact PhC's towards monolithic PICs based on InP. We describe in this talk the various aspects from technology to functions and devices, as emerged from the European collaboration "PCIC". The main technology tour de force is deep-etching with aspect ratio of about 10 and vertical sidewall, achieved by three techniques (CAIBE, ICP-RIE, ECR-RIE). The basic functions explored are bends, splitters/combiners, mirrors, tapers, and the devices are filters and lasers. At the end of the talk, I will emphasize some positive aspects of "broad" multimode PhC waveguides, in view of compact add-drop filtering action, notably.
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| 3. |
- 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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| 4. |
- Ferrini, R., et al.
(författare)
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Optical study of two-dimensional InP-based photonic crystals by internal light source technique
- 2002
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Ingår i: IEEE Journal of Quantum Electronics. - 0018-9197 .- 1558-1713. ; 38:7, s. 786-799
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Tidskriftsartikel (refereegranskat)abstract
- We present the first optical study of 2-D photonic crystals (PCs) deeply etched in an InP/GaInAsP step-index waveguide. Following the same internal light source approach proposed by Labilloy and coworkers for the investigation of GaAs-based 2-D PCs, transmission measurements through simple PC slabs and 1-D Fabry-Perot (FP) cavities between PC mirrors were performed. Details are given on the experimental setup which has been implemented with respect to the original scheme and adapted to InP-based systems working at 1.5-mum. 2-D plane-wave expansion and finite difference time-domain (FDTD) methods are used to fit the experimental data. Out-of-plane losses were evaluated according to a recently introduced phenomenological model. In spite of the complex hole morphology in the measured samples, preliminary results are presented which indicate the possibility of separating different loss contributions from finite etch depth and hole shape. As for 1-D cavities, both FDTD and classical theory for planar resonators are applied in order to deduce the optical properties of the PC mirrors. The origin of an anomalously high transmission observed inside the stopgap is discussed and arguments are given to demonstrate the need for further modeling efforts when working in the bandgap regime.
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| 5. |
- Ferrini, R., et al.
(författare)
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Radiation losses in planar photonic crystals : two-dimensional representation of hole depth and shape by an imaginary dielectric constant
- 2003
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Ingår i: Journal of the Optical Society of America. B, Optical physics. - 0740-3224 .- 1520-8540. ; 20:3, s. 469-478
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Tidskriftsartikel (refereegranskat)abstract
- Waveguide modes in two-dimensional (2-D) photonic crystals (PhCs) deeply etched through monomode slab waveguides, e.g., AlGaAs/GaAs, GaAs/AlOx, or InP/GaInAsP, suffer from radiation losses that are strongly affected by the air hole depth and shape. The issue of three-dimensional (3-D) out-of-plane losses is addressed analytically by means of an incoherent approximation. Assuming separability both for the dielectric map and for the electric field, this approach is valid for defects such as in-plane microcavities, PhC-based waveguides, bends and couplers. Out-of-plane scattering is translated into an effective imaginary index in the air holes, so that 3-D losses can be cast in a simple 2-D calculation. The case of cylindroconical holes is treated, and the validity of this approach is experimentally confirmed by transmission measurements through simple PhC slabs.
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| 7. |
- Huang, Z. L., et al.
(författare)
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Novel heterocycle-based organic molecules with two-photon induced blue fluorescent emission
- 2003
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 13:4, s. 708-711
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Tidskriftsartikel (refereegranskat)abstract
- Two-photon absorption and two-photon induced blue emission characteristics of a series of heterocycle-based organic molecules are investigated experimentally and by quantum-chemical computations. The molecules consist of a typical A-pi-A' structure, where heterocycle, styryl and formyl groups are employed as A, pi-conjugated and A' moieties, respectively. Experimental results indicate that significant enhancements in the blue emission efficiency and two-photon absorption cross-sections can be achieved by replacing S and O atoms with an N atom in the heterocycle acceptor moiety, which is also supported by the quantum-chemical computations. Additionally, larger two-photon absorption cross-sections can be obtained by choosing appropriate solvents, as indicated by the computations.
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| 8. |
- Olivier, S., et al.
(författare)
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Resonant and nonresonant transmission through waveguide bends in a planar photonic crystal
- 2001
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 79:16, s. 2514-2516
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Tidskriftsartikel (refereegranskat)abstract
- We have measured the near-infrared transmission spectra of 60 degrees bends defined in two-dimensional photonic crystal waveguides consisting of three missing rows. Two limit cases are studied: a basic nonresonant bend and a bend built around a resonant lozenge cavity, which is found to exhibit peaked transmission. Finite-difference-time-domain simulations show very good agreement with the data allowing general design issues for efficient bends to be discussed.
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