Monolithic integrated reflective transceiver in indium phosphide

The work presented in this thesis is about an InP based monolithic integrated reflective transceiver meant for use in future fiber access networks at the user site. The motivation for this research results from the users’ demands for ever-increasing bandwidth at low cost of operation, administration and maintenance. We investigated solutions to these challenges with a network concept using a dynamically reconfigurable optical network topology with a wavelength router and a colorless optical network unit. This work focuses on developing the optical part of the optical network unit, a reflective transceiver. This reflective transceiver consists of three basic components: a tunable wavelength duplexer, a photodetector and a reflective modulator. The tunable wavelength duplexer separates two wavelengths, one for the downstream and one for the upstream signals, and guides them to the photodetector and the reflective modulator. The photodetector detects the downstream data. The reflective modulator modulates the light carrier with the upstream data and reflects it back to the network. The integrated transceiver was realized bymonolithically integrating these components on a common active-passive butt-joint layer stack based on InP technology. This approach not only offers high bandwidth for both downstream data and upstream data, but also lowers the cost of the device and the network operation because of the colorless operation at the user site. The main results obtained within this work are summarized as follows: an efficient and polarization insensitive tunable wavelength duplexer was realized; a new method to fabricate a reflective SOA has been proposed and demonstrated; a high performance waveguide photodetector based on SOA layer stack was successfully fabricated; a low cost photoreceiverwhich includes an InP photodetector and a SiGe amplifier was demonstrated; aworking monolithic integrated reflective transceiver based on InP was successfully realized and demonstrated; two monolithic integrated transceivers aiming for higher bandwidth have been designed and fabricated. In addition, a novel MMI reflector has been proposed and realized with high reflectivity. This work was funded by DutchMinistry of Economic Affairs through the Freeband Project Broadband Photonics Access, the Smartmix projectMemphis and the NRC Photonics

MAP Kinase Phosphatase-2 Plays a Critical Role in Response to Infection by Leishmania mexicana

In this study we generated a novel dual specific phosphatase 4 (DUSP4) deletion mouse using a targeted deletion strategy in order to examine the role of MAP kinase phosphatase-2 (MKP-2) in immune responses. Lipopolysaccharide (LPS) induced a rapid, time and concentration-dependent increase in MKP-2 protein expression in bone marrow-derived macrophages from MKP-2+/+ but not from MKP-2−/− mice. LPS-induced JNK and p38 MAP kinase phosphorylation was significantly increased and prolonged in MKP-2−/− macrophages whilst ERK phosphorylation was unaffected. MKP-2 deletion also potentiated LPS-stimulated induction of the inflammatory cytokines, IL-6, IL-12p40, TNF-α, and also COX-2 derived PGE2 production. However surprisingly, in MKP-2−/− macrophages, there was a marked reduction in LPS or IFNγ-induced iNOS and nitric oxide release and enhanced basal expression of arginase-1, suggesting that MKP-2 may have an additional regulatory function significant in pathogen-mediated immunity. Indeed, following infection with the intracellular parasite Leishmania mexicana, MKP-2−/− mice displayed increased lesion size and parasite burden, and a significantly modified Th1/Th2 bias compared with wild-type counterparts. However, there was no intrinsic defect in MKP-2−/− T cell function as measured by anti-CD3 induced IFN-γ production. Rather, MKP-2−/− bone marrow-derived macrophages were found to be inherently more susceptible to infection with Leishmania mexicana, an effect reversed following treatment with the arginase inhibitor nor-NOHA. These findings show for the first time a role for MKP-2 in vivo and demonstrate that MKP-2 may be essential in orchestrating protection against intracellular infection at the level of the macrophage

An integrated transceiver based on a reflective semiconductor optical amplifier for the access network

In this paper, a reflective transceiver is presented which monolithically integrates a wavelength duplexer, a reflective SOA (RSOA) and a detector. The first characterization shows that the wavelength duplexer obtained better than -15 dB optical isolation between the upstream and downstream signals. The polarization dependence was less than 25% of the 200 GHz (1.6 nm) channel spacing over a 50 nm wavelength range. A 750 µm long RSOA achieved around 20 dB on-chip gain, and a 30 µm long photodetector shows good responsivity of up to 0.25~0.4 A/W within a 50 nm operating range at -2V bias voltage

An integrated transceiver based on a reflective semiconductor optical amplifier for the access network

In this paper, a reflective transceiver is presented which monolithically integrates a wavelength duplexer, a reflective SOA (RSOA) and a detector. The first characterization shows that the wavelength duplexer obtained better than -15 dB optical isolation between the upstream and downstream signals. The polarization dependence was less than 25% of the 200 GHz (1.6 nm) channel spacing over a 50 nm wavelength range. A 750 µm long RSOA achieved around 20 dB on-chip gain, and a 30 µm long photodetector shows good responsivity of up to 0.25~0.4 A/W within a 50 nm operating range at -2V bias voltage

Hybrid InP-SiGe photoreceiver for the access network

In this paper, we present a low cost and polarization independent photoreceiver which is part of the optical network unit (ONU) for the fiber access network. It consists of one InP-photodetector and a low cost SiGe amplifier. It operates error free with 223 - 1 PRBS word length at 1.25 Gbit/s with -13dBm input optical power before the fiber chip coupling whose loss is about 5 dB. From the rise and fall time shown in measured eyediagram, it is estimated that it will also operate up to 2.5 Gbit/s

Brain-inspired algorithms for retinal image analysis

\u3cp\u3eRetinal image analysis is a challenging problem due to the precise quantification required and the huge numbers of images produced in screening programs. This paper describes a series of innovative brain-inspired algorithms for automated retinal image analysis, recently developed for the RetinaCheck project, a large-scale screening program for diabetic retinopathy and other retinal diseases in Northeast China. The paper discusses the theory of orientation scores, inspired by cortical multi-orientation pinwheel structures, and presents applications for automated quality assessment, optic nerve head detection, crossing-preserving enhancement and segmentation of retinal vasculature, arterio-venous ratio, fractal dimension, and vessel tortuosity and bifurcations. Many of these algorithms outperform state-of-the-art techniques. The methods are currently validated in collaborating hospitals, with a rich accompanying base of metadata, to phenotype and validate the quantitative algorithms for optimal classification power.\u3c/p\u3