Integration of semiconducting carbon nanotubes within a silicon photonic molecule

Integration of nanomaterials within optical nanocavities provides a unique potential for flexible control of light emitters properties by photonic band gap engineering and cavity Purcell effects. Here, we propose a one-dimensional heterostructure nanocavity exhibiting both non-coupled and coupled cavity modes, i.e. simultaneously acting as a single cavity and as a photonic molecule. The main cavity resonances are engineered to yield a wide spectral separation and for the first time to match the emission wavelengths of two different kinds of semiconducting single wall carbon nanotubes (s-SWNTs). By probing the photoluminescence (PL) from s-SWNTs coupled with the nano cavity modes, coupling of the s-SWNTs PL simultaneously into the several cavity modes is demonstrated. For modes governed by the photonic molecule behavior, the wavelength splitting of the two coupled modes is dominated by the cavity barrier width. The excitation of the bonding (B) and anti-bonding (AB) cavity modes then yields PL resonant enhancement that can be tuned by the pumping position and polarization filter. These results demonstrate the potential of the proposed multimode photonic molecule to tailor light-nanomaterial interactions on chip, paving the way for the development of tunable hybrid photonic circuits relying on nanoemitters in cavities for light generation purposes

Efficient excitation of silicon photonic cavity modes from carbon nanotube photoluminescence

International audienceWe report here the integration of a large quantity of s-SWCNTs as an active cladding layer on top of silicon micro/nano cavities. The gathered results show that the luminescence of the SCNTs can be efficiently coupled into the considered photonic crystal cavity modes

Broadband Polarization Beam Splitter on a Silicon Nitride Platform for O-Band Operation

International audienceWideband polarization beam splitters (PBS) are a key building block in polarization management circuits for wavelength division multiplexing applications. A broadband PBS on a 300-mm silicon nitride (SiN) photonic platform is reported based on phase-controlled directional coupler (DC). Unlike classical DC-based PBS made on silicon, the proposed configuration leverages the comparatively lower birefringence in SiN to yield wideband and efficient splitting. A semi-analytical approach, based on transfer matrix modeling and 3-D finite difference time domain, has been used to design and optimize the structure for O-band operation. The proposed PBS has been experimentally demonstrated showing insertion loss (IL) lower than 0.6 dB and extinction ratio (ER) as high as 10 dB over 95-nm bandwidth for both polarizations. Furthermore, this simplified architecture eases cascading, allowing the demonstration of IL below 1.1 dB and ER larger than 24 dB over 85-nm wavelength range in a dual-stage configuration

Polarization-Sensitive Single-Wall Carbon Nanotubes All-in-One Photodetecting and Emitting Device Working at 1.55 µm

International audienceFunctional and easy-to-integrate nanodevices operating in the telecom wavelength ranges are highly desirable. Indeed, the pursuit for faster, cheaper, and smaller transceivers for datacom applications is fueling the interest in alternative materials to develop the next generation of photonic devices. In this context, single wall carbon nanotubes (SWNTs) have demonstrated outstanding electrical and optical properties that make them an ideal material for the realization of ultracompact optoelectronic devices. Still, the mixture in chirality of as-synthesized SWNTs and the necessity of precise positioning of SWNT-based devices hinder the development of practical devices. Here, the realization of operational devices obtained using liquid solution-based techniques is reported, which allow high-purity sorting and localized deposition of aligned semiconducting SWNTs (s-SWNTs). More specifically, devices are demonstrated by combining a polymer assisted extraction method, which enables a very effective selection of s-SWNTs with a diameter of about 1–1.2 nm, with dielectrophoresis, which localizes the deposition onto silicon wafers in aligned arrays in-between prepat-terned electrodes. Thus, long semiconducting nanotubes directly contact the electrodes and, when asymmetric contacts (i.e., source and drain made of different metals) are used, each device can operate both as photoemitter and as photodetector in the telecom band around 1.55 µm in air at room temperature

Erbium-doped hybrid waveguide amplifiers with net optical gain on a fully industrial 300 mm silicon nitride photonic platform

| openaire: EC/H2020/820423/EU//S2QUIP | openaire: EC/H2020/834742/EU//ATOPRecently, erbium-doped integrated waveguide devices have been extensively studied as a CMOS-compatible and stable solution for optical amplification and lasing on the silicon photonic platform. However, erbium-doped waveguide technology still remains relatively immature when it comes to the production of competitive building blocks for the silicon photonics industry. Therefore, further progress is critical in this field to answer the industry's demand for infrared active materials that are not only CMOS-compatible and efficient, but also inexpensive and scalable in terms of large volume production. In this work, we present a novel and simple fabrication method to form cost-effective erbium-doped waveguide amplifiers on silicon. With a single and straightforward active layer deposition, we convert passive silicon nitride strip waveguide channels on a fully industrial 300 mm photonic platform into active waveguide amplifiers. We show net optical gain over sub-cm long waveguide channels that also include gratingcouplers and mode transition tapers, ultimately demonstrating tremendous progress in developing cost-effective active building blocks on the silicon photonic platform. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing AgreementPeer reviewe

Near-Field Fano-Imaging of TE and TM Modes in Silicon Microrings

International audienceA deep-subwavelength imaging of the optical-guided modes localized in silicon microring resonators, obtained with a polarization-sensitive Fano-imaging technique, is demonstrated. We merge together near-field scanning optical microscopy and resonant forward scattering spectroscopy, leading to near-field hyperspectral imaging without the need of embedded light emitters or evanescent light coupling into the microring. The combined analysis of the observed Fano-like spectral line shapes and of the near-field intensity spatial distributions, supported by accurate numerical calculations, gives a clear discrimination between the TE and the TM modes

Dual-polarization silicon nitride Bragg filters with low thermal sensitivity

International audienceWideband and polarization-independent wavelength filters with low sensitivity to temperature variations have great potential for wavelength division multiplexing applications. However, simultaneously achieving these metrics is challenging for silicon-on-insulator photonics technology. Here, we harness the reduced index contrast and the low thermo-optic coefficient of silicon nitride to demonstrate waveguide Bragg grating filters with wideband apolar rejection and low thermal sensitivity. Filter birefringence is reduced by judicious design of a triangularly shaped lateral corrugation. Based on this approach, we demonstrate silicon nitride Bragg filters with a measured polarization-independent 40 dB optical rejection with negligible off-band excess loss, and a sensitivity to thermal variations below 20 pm/°C

Heterogeneous Integration of Doped Crystalline Zirconium Oxide for Photonic Applications

Hybrid integration of new materials will play a key role in the next photonics revolution, unlocking the development of advanced devices with outstanding performances and innovative functionalities. Functional oxides, thanks to the richness of their physical properties are promising candidates to build active reconfigurable elements in complex circuits. We review in this article our recent work regarding the hybrid integration of Yttria-Stabilized Zirconia (YSZ), a crystalline oxide with transparency from the visible to the mid-IR range with refractive index of about 2.15. YSZ is mostly studied for its high ionic conductivity, epitaxial growth on Si as buffer layer and its chemical stability but we demonstrated that it also holds a great potential in photonics for the development of low-loss waveguides (<2 dB/cm) and complex passive structures. Kerr refractive index of YSZ is in the same order of magnitude than well-known nonlinear materials such as silicon nitride. We explored the implementation of Er 3+ ions as an active element providing outstanding luminescence in correspondence with C-band of telecommunications. The optical properties of active layers of Er-doped YSZ grown on waveguides in different platforms and under resonant pumping and its propagation losses, modal gain and signal enhancement will be discussed in this paper

Hybrid integration of carbon nanotubes in silicon photonic structures

International audienceSilicon photonics, due to its compatibility with the CMOS platform and unprecedented integration capability, has become the preferred solution for the implementation of next generation optical interconnects to accomplish high efficiency, low energy consumption, low cost and device miniaturization in one single chip. However, it is restricted by silicon itself. Silicon does not have efficient light emission or detection in the telecommunication wavelength range (1.3 μm-1.5 μm) or any electro-optic effect (i.e. Pockels effect). Hence, silicon photonic needs to be complemented with other materials for the realization of optically-active devices, including III-V for lasing and Ge for detection. The very different requirement of these materials results in complex fabrication processes that offset the cost-effectiveness of the Si photonics approach. For this purpose, carbon nanotubes (CNTs) have recently been proposed as an attractive one-dimensional light emitting material. Interestingly, semiconducting single walled CNTs (SWNTs) exhibit room-temperature photo- and electro-luminescence in the near-IR that could be exploited for the implementation of integrated nano-sources. They can also be considered for the realization of photo-detectors and optical modulators, since they rely on intrinsically fast non-linear effects, such as Stark and Kerr effect. All these properties make SWNTs ideal candidates in order to fabricate a large variety of optoelectronic devices, including near-IR sources, modulators and photodetectors on Si photonic platforms. In addition, solution processed SWNTs can be integrated on Si using spin-coating or drop-casting techniques, obviating the need of complex epitaxial growth or chip bonding approaches. Here, we report on our recent progress in the coupling of SWNTs light emission into optical resonators implemented on the silicon-on-insulator (SOI) platform