Merger of Electronics and Photonics Using Silicon Based Technologies

Informazioni relative al progetto

MEPHISTO

ID dell’accordo di sovvenzione: 511466

Progetto chiuso

Data di avvio 1 Agosto 2004

Data di completamento 31 Dicembre 2008

Finanziato da

• Information Society Technologies: thematic priority under the specific programme "Integrating and strengthening the European research area" (2002-2006).

Costo totale € 4 052 954,00

Contributo UE € 2 099 966,00

Coordinato da

FRAUNHOFER-GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V
Germany

Exploitable results

Hybrid integration for silicon on insulator technology

The increasing demand for photonics components featuring enhanced functionality, complexity, miniaturisation, performance and reliability and requiring reduced assembly costs is believed to be achievable only by integration technologies. In particular, the call for smaller and smaller footprint of devices has been attracting much awareness today in order to accommodate more functions in smaller form factor modules. Basically the integration technologies pursued worldwide may be divided into the following categories: Monolithic integration using one common material system for the different devices to be integrated. Compound semiconductors – for telecommunication applications usually InP based compounds – are the materials of choice, in principal allowing for implementing all the active and passive optical functions desired for those components, and electronic devices as well. Having been a dream since the late 1970s this approach has seen remarkable progress in recent years, especially driven by the US company Infinera. with hybrid integration different material technologies are employed to "take the best from different worlds". Integration is accomplished by attaching different device chips - such as laser and photodiodes, SOA, electronic Ics, but also thin film filters - to an optical waveguide board utilizing suitable micro/nano-assembly techniques. To this end different material platforms are utilised including silica-on-silicon, SiON, ion-exchanged glass, and also polymers, each of them having inherent virtues and drawbacks. Hybrid integration itself offers advantages with respect to optimising overall performance due to application of different materials; yield management; versatility and flexibility, and others. The latter aspect renders this technology especially useful for small to medium production volumes. an integration platform that has attracted extremely high interest in recent years is silicon-oninsulator (SOI) where Si acts as core waveguide layer optically isolated from the Si substrate by an intermediate SiO2 layer. Using this material optical waveguides of widely varying dimensions and related device structures can be implemented, and naturally electronic circuitries. In addition, realisation of high-speed electrooptical modulators was successfully demonstrated by different groups, and if combined with Ge films high-speed detectors can also be monolithically integrated. In this way SOI can serve as platform for quasi-monolithic integration ("Si Photonics") as well as for traditional hybrid integration, and can hence cover a wide intermediate range between truly monolithic and hybrid optical integration. What is still far out of reach is the realisation of practical Si based laser structures still necessitating hybridisation for such devices. One major advantage of using SOI is the CMOS fabrication compatibility thus exploiting all the advantages of Si technology. Further synergy is offered by the wide use of SOI in MEMS applications. potential applications once developed hybrid integration is believed to be applicable to a large number of photonic components in a versatile manner. Applications will be not only in the field of optical telecommunications and data communications but also in optical interconnections, sensors and metrology, and related areas. An example may be a broadband light source for fiber sensors or optical coherence tomography applications being comprised of multiplexed LED spectra. Multi-wavelength integrated transmitters in particular will be very useful in different parts of optical networks. Different wavelength channel spacings ranging from DWDM (> 50GHz/0.4 nm spacing) to CWDM (20 nm) including intermediate solutions (dCWDM, e.g. 5; 10 nm) will be applied. 4x10 Gb/s to enable low-cost 40 Gb/s transmission, and 4x25Gb/s and even 10x10 Gb/s for 100 Gb/s transmission are potential solutions that were recently agreed in standardization bodies concerned. In the frame of next generation optical access networks use of both CWDM and DWDM technology is intensely being discussed. For this low-cost transmitter and receiver devices with a large number of channel counts and low footprint are demanded. In view of these perspectives the goals of the Mephisto project were well defined even before these applications really emerged. scientific and commercial exploitation an innovative DFB laser structure (referred to as CSDFB) has been introduced and demonstrated by partner Fraunhofer-HHI that simultaneously offers the following advantages: - low beam divergence - high slope efficiency - high single-mode yield even without antireflection facet coating - high single-mode stability particularly at low operation temperature (down to – 40°C). - superior feedback sensitivity as compared to conventional DFB designs In the end these features lead to lower device costs because of high SM yield, potential elimination of an optical isolator, and easier mounting thanks to the taper structure inherently involved. These combined features are highly attractive for any DFB laser application not only in the telecom/datacom arena but also for sensors & instrumentation (e. g. gas analysis) and related applications. For this invention an European patent (EP1677396B1, January 2007) and a German utility patent (DE 20320771) have been granted. The CSDFB laser has been and is being used by HHI as a key device in various national R&D projects (COMAN, Berlin Access, TOSA, MiniWDM) in which HHI is participating in collaboration with different industrial partners to target marketable products. In particular, HHI is now using this device as the preferred laser source in the frame of their polymer PLC based hybrid integration technology. as a summary benefits Okmetic gained from the Mephisto project were: - enhanced competitiveness in SOI products - improved quality enabling penetration to new customers and end-products - 200 mm SOI product introduction - C-SOI quality improvement and widened design rules - greatly increased production volumes freescale Halbleiter Deutschland GmbH, in MEPHISTO having developed low- impedance SiGe BICMOS based 10Gb/s laser driver circuits, initially intended to enter the emerging 10Gb/s optical communication market but did not see real market opportunities during the recent “down turn” period of that market. However Freescale might reconsider in case of a strongly growing demand from potential customers for laser driver chips at 10 Gb/s or higher. Licensing could be another option for exploitation.