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Ottawa, Canada

Raghunathan V.,Massachusetts Institute of Technology | Ye W.N.,Carleton University | Hu J.,Massachusetts Institute of Technology | Izuhara T.,Enablence Technologies | And 2 more authors.
Optics Express | Year: 2010

We report the design criteria and performance of Si ring resonators for passive athermal applications in wavelength division multiplexing (WDM). The waveguide design rules address i) positivenegative thermo-optic (TO) composite structures, ii) resonant wavelength dependent geometry to achieve constant confinement factor (Γ) and iii) observation of small residual second order effects. We develop exact design requirements for a temperature dependent resonant wavelength shift (TDWS) of 0 pm/K and present prototype TDWS performance of 0.5pm/K. We evaluate the materials selection tradeoffs between high-index contrast (HIC) and low-index contrast (LIC) systems and show, remarkably, that FSR and footprint become comparable under the constraint of athermal design. © 2010 Optical Society of America. Source

Raghunathan V.,Massachusetts Institute of Technology | Izuhara T.,Enablence Technologies | Michel J.,Massachusetts Institute of Technology | Kimerling L.,Massachusetts Institute of Technology
Optics Express | Year: 2012

Temperature sensitivity of Si based rings can be nullified by the use of polymer over-cladding. Integration of athermal passive rings in an electronic-photonic architecture requires the possibility of multi-layer depositions with patterned structures. This requires establishing UV, thermal and plasma stability of the polymer during multi-layer stacking. UV stability is enhanced by UV curing to saturation levels. However, thermal stability is limited by the decomposition temperature of the polymer. Further, robust performance in oxidizing atmosphere and plasma exposure requires a SiO 2/SiNx based dielectric coatings on the polymer. This communication uses a low temperature (130°C) High Density Plasma Chemical Vapor Deposition (HDPCVD) for dielectric encapsulation of polymer cladded Si rings to make them suitable for device layer deposition. UV induced cross-linking and annealing under vacuum make polymer robust and stable for Electron Cyclotron Resonance (ECR)-PECVD deposition of 500nm SiO2/SiNx. The thermo-optic (TO) properties of the polymer cladded athermal rings do not change after dielectric cap deposition opening up possibilities of device deposition on top of the passive athermal rings. Back-end CMOS compatibility requires polymer materials with high decomposition temperature (> 400°C) that have low TO coefficients. This encourages the use of SiNx core waveguides in the backend architecture for athermal applications. © 2012 Optical Society of America. Source

Balakrishnan A.,Enablence Technologies
Photonics Spectra | Year: 2010

The availability of bandwidth-intensive services such as fiber-to-the-home, along with bandwidth requirements in the commercial sector, has led to the increased demand for the introduction of new 40G/100G optical networks. The optical chips are fabricated using wafer-level processing techniques, and they use optical waveguides to route photons the same way that metal traces are used to route electrons in an electronic chip. The planar lightwave circuits (PLC) modules for 40G/100G applications require several subcomponents including fiber interface, a wavelength filter or combiners, polarization control and polarization-based splitting/combining, optical isolators, laser sources and detectors. Optical receivers are fabricated by integrating photodiodes on the PLC chip itself. The PLC platform allows the transimpedance amplifier (TIA) to be mounted on the optical chip platform, directly adjacent to the photodetector, ensuring optimal signal integrity at high data rates. Source

Pearson M.,Enablence Technologies
Lightwave | Year: 2010

Planar lightwave circuit (PLC) technology has evolved significantly in several areas including advanced 40G/100G applications. The 100G links can be supported in two ways such as through the use of DWDM or through advanced modulation formats such as differential quadrature phase-shift keying (DQPSK) and polarization-multiplexed quadrature phase-shift keying (PM-QPSK). PLC provide a means to integrate thermo-optic phase shifters throughout the optical chip, which enables active phase control that can be adjusted as necessary and monitored in real time. Several laser diodes used in telecommunications rely on thermal tuning to ensure the laser wavelength remains in the correct location on the ITU grid. PLCs can be designed with impedance-matched electrical traces, which are used to interface detectors with TIAs and package feedthroughs. PLC provides opportunities for integrating the functionality from optical components onto a single PLC platform that is suitable for high-volume assembly. Source

Khan K.R.,University of Ottawa | Bidnyk S.,University of Ottawa | Bidnyk S.,Enablence Technologies | Hall T.J.,University of Ottawa
Progress In Electromagnetics Research M | Year: 2012

We propose an all optical switch in a dual-core photonic crystal fiber (PCF) that has the core region consisting of soft glass and has nematic liquid crystal filled holes in the cladding region. Light waves are guided in this PCF by total internal reflection (TIR) due to the refractive index contrast between soft glass and liquid crystal (LC). Its wavelength dependent coupling, birefringence and dispersion are calculated and later use these parameters to evaluate the switching characteristics of short pulses propagating through this optical waveguide. The switch demonstrates tunability with external perturbation such as applying external heat source or electric field. Refractive index sensitivity of LC with these perturbation as well as polarization of the light signal determines the coupling, birefringence and dispersion properties of the overall waveguide and its switching characteristics. Source

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