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Dortmund, Germany

Rautiainen J.,Tampere University of Technology | Krestnikov I.,Innolume Gmbh | Nikkinen J.,Tampere University of Technology | Okhotnikov O.G.,Tampere University of Technology
Optics Letters | Year: 2010

We report a disk laser using two quantum-dot semiconductor gain elements, resulting in what we believe is the first demonstration of intracavity frequency conversion with these active media. Output power of 6 W has been obtained in dual-gain configuration at a wavelength of 1180 nm, while single-gain lasers produced up to 3 and 4 W individually, limited by thermal rollover in the output characteristics. The gain enhancement achieved with two active elements comprising 39 layers of Stranski-Krastanov InGaAs quantum dots allows for intracavity frequency doubling delivering 2:5 W of orange radiation. © 2010 Optical Society of America.

Hoffmann M.C.,University of Hamburg | Monozon B.S.,Saint Petersburg State University | Livshits D.,Innolume Gmbh | Rafailov E.U.,University of Dundee | Turchinovich D.,Technical University of Denmark
Applied Physics Letters | Year: 2010

We demonstrate an instantaneous all-optical manipulation of optical absorption in InGaAs/GaAs quantum dots (QDs) via an electro-absorption effect induced by the electric field of an incident free-space terahertz signal. A terahertz signal with the full bandwidth of 3 THz was directly encoded onto an optical signal probing the absorption in QDs, resulting in the encoded temporal features as fast as 460 fs. The instantaneous nature of this effect enables femtosecond all-optical switching at very high repetition rates, suggesting applications in terahertz-range wireless communication systems with data rates of at least 0.5 Tbit/s. © 2010 American Institute of Physics.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2013.3.2 | Award Amount: 5.03M | Year: 2013

Silicon photonics is a powerful way to combine the assets of integrated photonics and CMOS technologies. The SEQUOIA project intends to make significant new advances in silicon photonic integrated circuits by heterogeneously integrating novel III-V materials, namely quantum dot and quantum dash-based materials on silicon wafers, through wafer bonding. Thanks to the superior properties of those innovative materials, hybrid III-V lasers with better thermal stability, higher modulation bandwidth and the possibility of generating a flat wavelength-division-multiplexing comb will be demonstrated. Moreover, the hybrid integration of nano-structured materials on Si allows to exploit the advantages provided by silicon. In particular, optical filters can be directly integrated with hybrid quantum dot/quantum dash/Si lasers to create chirp-managed lasers, which have an enhanced modulation bandwidth and extinction ratio compared to directly modulated lasers. As an illustration of the technology developed in SEQUOIA, transmitters with a total capacity of 400 Gbit/s (16x25 Gbit/s) will be designed, fabricated and characterized. The hybrid integration of nano-structured III-V materials in silicon through a wafer bonding technique is generic, and the concepts and technology developed inside the SEQUOIA project can be further extended to other types of transmitters, for example with extended link range, higher bit rate, higher WDM channel number and other types of modulation formats. In addition, a broad range of applications, such as sensing, health-care, safety and security, can benefit from the technology developed in SEQUOIA.The SEQUOIA consortium is highly complementary, covering all skills required to achieve the project objectives, from the growth of the nano-structured materials to the assessment of high bit rate digital communication systems, and has the potential to set up a comprehensive supply chain for the future exploitation.

A transversely-coupled distributed feedback laser diode, which can be processed without overgrowth, is disclosed. The laser is made from an epitaxial heterostructure including a core layer located between two cladding layers, a cap layer, and at least one Al-rich layer. The lateral waveguide is formed by selective oxidation of the Al-rich layer. A surface corrugated grating is formed above the waveguide. The heteroepitaxial structure is designed so that the core layer is placed in close proximity to the top of the laser structure to provide a required overlap between the light and the grating. In order to avoid inadmissible optical losses, there is no metallization above the waveguide. Instead, the metal contacts are offset at some distance, so that the current has to spread in the cap layer before vertical injection into the core layer.

Waveguide designs and fabrication methods provide adiabatic waveguide eigen mode conversion and can be applied to monolithic vertical integration of active and passive elements in PICs. An advantage of the designs and methods is a simple fabrication procedure with only a single etching step in combination with subsequent well-controllable selective oxidation. As a result, improved manufacturability and reliability can be achieved.

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