Reconfigurable photonic integrated circuits (RPICs) based on functional materials for integrated optical communication applications

This is the final version. Available from the publisher via the DOI in this record.In this work we combine the already mature silicon and silicon nitride platforms with novel reconfigurable materials such as 2D materials, liquid crystals and phase change materials. An actively reconfigurable 1D photonic crystal multi-channel filter based on Si-on-insulator and liquid crystal platforms is demonstrated with extraordinary large quality factor, Q ∼ 104 . A complete study and design of an optical routing and multilevel volatile photonic memory based on graphene capacitor concept for future high performance computing using Silicon rich nitride is shown with a bandwidth of 64 GHz and energy power consumption per bit as low as 0.22 pJ. Finally, an optical switch based on germanium-antimony-tellurium phase change material (GST) is experimentally demonstrated for O-band operation with the extinction ratio as high as 10 dB between the amorphous and the crystalline statesEngineering and Physical Sciences Research Council (EPSRC

Performance characteristics of phase-change integrated silicon nitride photonic devices in the O and C telecommunications bands

This is the final version. Available on open access from the Optical Society via the DOI in this recordData Availability: Data relating to this manuscript can be obtained from the authors.The evaluation and comparison of the optical properties in the O and C bands of silicon nitride rib waveguides with integrated Ge2Sb2Te5 phase-change cells is reported. In straight rib waveguides, a high transmission contrast is observed in both bands when the Ge2Sb2Te5 cell is switched between states, being up to 2.5 dB/μm in the C-band and 6.4 dB/μm in the O-band. In the case of silicon nitride ring resonator waveguides, high quality factor resonances (Q ∼ 105) are found in both bands, leading to the provision of an ON-OFF switch characterized by an extinction ratio of 12 and 18 dB in O and C bands respectively. Finally, with the view to provide a comparison of the wavelength-dependent optical switching of the phase-change cell, a 3-dimensional finite-element method simulation is performed and a comparison of the optical-to-thermal energy conversion in both bands given.European Union Horizon 2020Engineering and Physical Sciences Research Council (EPSRC

Towards low loss non-volatile phase change materials in mid index waveguides

Photonic integrated circuits currently use platform intrinsic thermo-optic and electro-optic effects to implement dynamic functions such as switching, modulation and other processing. Currently, there is a drive to implement field programmable photonic circuits, a need which is only magnified by new neuromorphic and quantum computing applications. The most promising non-volatile photonic components employ phase change materials such as GST and GSST, which had their origin in electronic memory. However, in the optical domain, these compounds introduce significant losses potentially preventing a large number of applications. Here, we evaluate the use of two newly introduced low loss phase change materials, Sb2S3 and Sb2Se3, on a silicon nitride photonic platform. We focus the study on Mach-Zehnder interferometers that operate at the O and C bands to demonstrate the performance of the system. Our measurements show an insertion loss below 0.04 dB/um for Sb2S3 and lower than 0.09 dB/um for Sb2Se3 cladded devices for both amorphous and crystalline phases. The effective refractive index contrast for Sb2S3 on SiNx was measured to be 0.05 at 1310 nm and 0.02 at 1550 nm, whereas for Sb2Se3, it was 0.03 at 1310 nm and 0.05 at 1550 nm highlighting the performance of the integrated device

Ultra-broadband Bragg scattering four wave mixing in silicon rich silicon nitride waveguides

We show the first demonstration of Bragg scattering inter-modal four-wave-mixing in silicon-rich SiN waveguides. We report wavelength conversion using two spatial modes, exhibiting a maximum efficiency of -15-dB over a flat-bandwidth in excess of 30-nm.</p

Tunable index silicon nitride for extended silicon photonics applications

We demonstrate PECVD based silicon nitride materials for range of applications. These applications are for non-linear functionalities in the C band, coarse wavelength division multiplexing in the O band and a 1-micron thick SiN waveguiding platform at 2 microns demonstrating filters and trimming capabilities

The emergence of silicon photonics as a flexible technology platform

In this paper, we present a brief history of silicon photonics from the early research papers in the late 1980s and early 1990s, to the potentially revolutionary technology that exists today. Given that other papers in this special issue give detailed reviews of key aspects of the technology, this paper will concentrate on the key technological milestones that were crucial in demonstrating the capability of silicon photonics as both a successful technical platform, as well as indicating the potential for commercial success. The paper encompasses discussion of the key technology areas of passive devices, modulators, detectors, light sources, and system integration. In so doing, the paper will also serve as an introduction to the other papers within this special issue.</p

GeSi absorption spectrum shift by mean of rapid thermal anneal

We report the results of absorption tunability of submicron rib waveguides based on Ge98.5%Si1.5% integrated into the Si platform. The transmission spectrum was characterised between 1520 nm and 1600 nm, before and after RTA annealing. The standard Tauc method was used to characterise the absorption profile of devices before and after thermal annealing. Material characterisation and simulations are also included to investigate the effect of RTA on the devices optical behaviour. A maximum blueshift of 38nm is reported using the proposed annealing technique which provides a cost-effective and efficient tool to tune the operational wavelength of devices such as electro-absorption modulators, realized on the SOI platform

Single crystal silicon-germanium-on-insulator for high density optical interconnects

The field of silicon photonics has seen a period of rapid technological advancement over the past decade, with significant interest and investment from both academia and industry. Progress is expected to continue, with global sales of silicon photonics products predicted to reach US 1 billion by 2020. A key motivation for silicon photonics is integration; achieved by using the CMOS compatible materials silicon and germanium. Here, we establish a silicon-germanium-on-insulator material platform using a rapid melt growth technique. We present a novel method for the fabrication of multiple, uniform composition localised silicon-germanium-on-insulator layers, demonstrating the ability to tune the composition of each layer by modifying the structural parameters of the layers, as shown in Fig. 1. This is achieved using only a single Ge growth step and a single anneal step, therefore dramatically reducing fabrication cost and complexity when compared with traditional epitaxy techniques.We investigate the regrowth mechanism exhibited by this rapid melt growth technique, and study the effects of the structural parameters of the tailored structures on the SiGe composition profiles. Using this material platform we can potentially exploit the tunable bandgap of the SiGe alloy for wavelength division multiplexing applications, with the potential to form low power electro-absorption modulators with an extremely high bandwidth density when compared to other modulator device designs. In addition, we discuss extending silicon photonic circuits into mid-infrared wavelengths, and identify the potential applications of such systems.We present some early results from passive mid-infrared photonic devices on a silicon-on-insulator platform

Silicon nitride CMOS platform for integrated optical phased arrays applications

We demonstrate devices and architectures enabling applications such as light detection and ranging (LiDAR) and optical switches, including dispersive optical phased array (OPA) architectures, a hybrid silicon nitride - lithium niobate on insulator (SiN - LNOI) optical phase modulator, and scalable architectures for optical switches.</p

Low-temperature NH₃-free silicon nitride platforms for integrated photonics

We demonstrate 3 platforms based on silicon nitride layers processed at 350°C and tailored to have different refractive indices. With these platforms, we have successfully fabricated low loss waveguides at telecom wavelengths, temperature tolerant (de)multiplexing devices, nonlinear waveguides, photonic crystal cavities and waveguides