Monolithic erbium- and ytterbium-doped microring lasers on silicon chips

We demonstrate monolithic 160-μm-diameter rare-earth-doped microring lasers using silicon-compatible methods. Pump light injection and laser output coupling are achieved via an integrated silicon nitride waveguide. We measure internal quality factors of up to 3.8 × 105 at 980 nm and 5.7 × 105 at 1550 nm in undoped microrings. In erbium- and ytterbium-doped microrings we observe single-mode 1.5-μm and 1.0-μm laser emission with slope efficiencies of 0.3 and 8.4%, respectively. Their small footprints, tens of microwatts output powers and sub-milliwatt thresholds introduce such rare-earth-doped microlasers as scalable light sources for silicon-based microphotonic devices and systems. © 2014 Optical Society of America

An engineering design knowledge reuse methodology using process modelling.

This paper describes an approach for reusing engineering design knowledge. Many previous design knowledge reuse systems focus exclusively on geometrical data, which is often not applicable in early design stages. The proposed methodology provides an integrated design knowledge reuse framework, bringing together elements of best practice reuse, design rationale capture and knowledge-based support in a single coherent framework. Best practices are reused through the process model. Rationale is supported by product information, which is retrieved through links to design process tasks. Knowledge-based methods are supported by a common design data model, which serves as a single source of design data to support the design process. By using the design process as the basis for knowledge structuring and retrieval, it serves the dual purpose of design process capture and knowledge reuse: capturing and formalising the rationale that underpins the design process, and providing a framework through which design knowledge can be stored, retrieved and applied. The methodology has been tested with an industrial sponsor producing high vacuum pumps for the semiconductor industry

Wavelength division multiplexed light source monolithically integrated on a silicon photonics platform

© 2017 Optical Society of America. We demonstrate monolithic integration of a wavelength division multiplexed light source for silicon photonics by a cascade of erbium-doped aluminum oxide (Al2O3:Er3+) distributed feedback (DFB) lasers. Four DFB lasers with uniformly spaced emission wavelengths are cascaded in a series to simultaneously operate with no additional tuning required. A total output power of -10.9 dBm is obtained from the four DFBs with an average side mode suppression ratio of 38.1 ± 2.5 dB. We characterize the temperaturedependent wavelength shift of the cascaded DFBs and observe a uniform dλ/dT of 0.02 nm/°C across all four lasers

Applying Belief Revision to Case-Based Reasoning

International audienceAdaptation is a task of case-based reasoning (CBR) that aims at modifying a case to solve a new problem. Now, belief revision deals also about modifications. This chapter studies how some results about revision can be applied to formalize adaptation and, more widely, CBR. Revision operators based on distances are defined in formalisms frequently used in CBR and applied to define an adaptation operator that takes into account the domain knowledge and the adaptation knowledge. This approach to adaptation is shown to generalize some other approaches to adaptation, such as rule-based adaptation

Athermal synchronization of laser source with WDM filter in a silicon photonics platform

© 2017 Author(s). In an optical interconnect circuit, microring resonators (MRRs) are commonly used in wavelength division multiplexing systems. To make the MRR and laser synchronized, the resonance wavelength of the MRR needs to be thermally controlled, and the power consumption becomes significant with a high-channel count. Here, we demonstrate an athermally synchronized rare-earth-doped laser and MRR. The laser comprises a Si3N4 based cavity covered with erbium-doped Al2O3 to provide gain. The low thermo-optic coefficient of Al2O3 and Si3N4 and the comparable thermal shift of the effective index in the laser and microring cross-sections enable lasing and resonance wavelength synchronization over a wide range of temperatures. The power difference between matched and unmatched channels remains greater than 15 dB from 20 to 50 °C due to a synchronized wavelength shift of 0.02 nm/°C. The athermal synchronization approach reported here is not limited to microring filters but can be applied to any Si3N4 filter with integrated lasers using rare earth ion doped Al2O3 as a gain medium to achieve system-level temperature control free operation