| 1. |
- 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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| 2. |
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| 3. |
- Mulot, Mikael, et al.
(författare)
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Fabrication of two-dimensional InP-based photonic crystals by chlorine based chemically assisted ion beam etching
- 2004
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Ingår i: Journal of Vacuum Science & Technology B. - : American Vacuum Society. - 1071-1023 .- 1520-8567. ; 22:2, s. 707-709
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional photonic crystals (PhCs) were etched into InP/(Ga,In)(As,P) planar waveguides using chlorine-based chemical assisted ion beam etching (CAIBE). The processed PhCs were optically characterized by measuring transmission through simple slabs and one-dimensional cavities. The optical performances inside the photonic band gap are much better compared to both previously reported CAIBE results and results obtained with other etching methods. In particular, we measured a record quality factor of 310 for one-dimensional cavities fabricated in this material system.
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| 4. |
- Valentinotti, S., et al.
(författare)
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Optimal operation of fed-batch fermentations via adaptive control of overflow metabolite
- 2003
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Ingår i: Control Engineering Practice. - Amsterdam : Elsevier Science. - 0967-0661 .- 1873-6939. ; 11:6, s. 665-674
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Tidskriftsartikel (refereegranskat)abstract
- The maximization of biomass productivity in the fed-batch fermentation of Saccharomyces cerevisiae is analyzed. Due to metabolic bottleneck, often attributed to limited oxygen capacity, ethanol is formed when the substrate concentration is above a critical value, which results in a decrease in biomass productivity. Thus, to maximize the production of biomass, the substrate concentration should be kept at the critical value. However, this value is unknown a priori and may change from experiment to experiment. A way to overcome this lack of knowledge is to allow the cells to produce a very small amount of ethanol. This way, the problem of maximizing the production of biomass is converted into that of regulating the concentration of ethanol, for which cell growth can be viewed as a perturbation. A novel adaptive control methodology based on the internal model principle is used to maintain the desired ethanol setpoint and reject the perturbation. Only a single parameter needs to be estimated on-line. Experimental results demonstrate the effectiveness of the proposed control methodology.
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| 5. |
- Wild, B., et al.
(författare)
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Temperature tuning of the optical properties of planar photonic crystal microcavities
- 2004
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Ingår i: Proc SPIE Int Soc Opt Eng. - : SPIE. ; , s. 311-317
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Konferensbidrag (refereegranskat)abstract
- We report on the temperature tuning of the optical properties of planar Photonic Crystal (PhC) microcavities. Studies were made on one and two dimensional PhCs that were etched in InP and GaAs vertical waveguides. Two dimensional (hexagonal) and one-dimensional (Fabry-Pérot) cavities were optically investigated by an internal light source technique. The samples were mounted on a Peltier-stage which allowed temperature variation from T = 20 °C up to T = 76 °C. A linear dependence of the resonance wavelengths with respect to temperature is observed. A gradient of dλ/dT = 0.09 nm/°C and 0.1 nm/°C for the GaAs and InP based cavities was observed, respectively. These results are in agreement with the theoretical calculations based on the thermal dependence of the refractive index of the PhC semiconductor component.
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| 6. |
- Wild, B., et al.
(författare)
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Temperature tuning of the optical properties of planar photonic crystal microcavities
- 2004
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 84:6, s. 846-848
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Tidskriftsartikel (refereegranskat)abstract
- We report on the temperature tuning of the optical properties of photonic crystal (PhC) microcavities. Planar and one-dimensional cavities were made from two-dimensional PhCs etched in GaAs and InP based vertical waveguides. These systems were optically characterized by an internal light source technique. The samples were mounted on a Peltier stage in order to vary the temperature from 20 to 76degreesC. Linear dependence of the resonance wavelengths with respect to the temperature is observed with gradients dlambda/dT=0.09 and 0.1 nm/degreesC for GaAs and InP based cavities, respectively. These results are in agreement with theoretical calculations based on the thermal dependence of the refractive index of the PhC semiconductor component.
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