This PDF file contains the front matter associated with SPIE Proceedings Volume 7942, including the Title Page, Copyright Information, Table of Contents, Conference Committee listing, and Introduction.

Integrated-optic devices enabling intra-board high-density optical interconnection with tens terabit-per-second transmission bandwidth from two-dimensional (2D) array of VCSELs to 2D array of photodiodes are reviewed. Design strategy and WDM signal transmission are discussed. A cavity-resonator-integrated grating input/output coupler and a different-guided-mode-coupling DBR are integrated to provide free-space-wave optical add/drop multiplexing function for a future high-performance signal-processing system in package using WDM optical interconnection. Design example of eight-wavelength multiplexing system within 20-nm wavelength range is presented and theoretically simulated performances are shown.

We consider the implementation of a dynamic crossbar interconnect using planar-integrated free-space optics (PIFSO) and a digital mirror-device™ (DMD). Because of the 3D nature of free-space optics, this approach is able to solve geometrical problems with crossings of the signal paths that occur in waveguide optical and electrical interconnection, especially for large number of connections. The DMD device allows one to route the signals dynamically. Due to the large number of individual mirror elements in the DMD, different optical path configurations are possible, thus offering the chance for optimizing the network configuration. The optimization is achieved by using an evolutionary algorithm for finding best values for a skewless parallel interconnection. Here, we present results and experimental examples for the use of the PIFSO/DMD-setup.

We present DWDM nanophotonics architectures based on microring resonator modulators and detectors. We focus on two implementations: an on chip interconnect for multicore processor (Corona) and a high radix network switch (HyperX). Based on the requirements of these applications we discuss the key constraints on the photonic circuits' devices and fabrication techniques as well as strategies to improve their performance.

We demonstrate a wide range of novel functions in integrated, CMOS compatible, devices. This platform has promise for telecommunications and on-chip WDM optical interconnects for computing.

The past decade has seen profound changes not only in the way we communicate, but also in our expectations of what networks will deliver in terms of speed and bandwidth. The coming decade promises to demand more capacity and bandwidth in these networks and it is in this context that we present our work on scaling technologies for terabit ber optic transmission systems. We discuss several topics that focus on increasing capacity in existing and next generation long-haul and metro ber optic transmission systems that will carry tens to hundreds of terabits and will be based on coherent optical receivers.

The integration of an opto-electronic mmW module for application to RF sensing and imaging is presented. Component integration consisting of ultra-broad band antennas, PIN switching, low noise amplifiers, and photonic phase modulator, is discussed. A fully integrated module working up to 130GHz is characterized and presented. Applications in a distributed aperture RF imaging system are discussed.

Advances in nanoscale fabrication techniques in dielectric and metallic material systems has opened up new opportunities in photonics and plasmonics for solving long standing problems in information systems and telecommunication systems. In this talk, we discuss some of the metamaterials and devices that recently have been demonstrated in our lab. These include metamaterials with space variant polarizability to realize on-chip, frequencyselective resonators and Bragg gratings, as well as metal-semiconductor-dielectric nanolasers.

Hybrid silicon lasers based on bonded III-V layers on silicon are discussed with respect to the challenges and trade-offs in their design and fabrication. Focus is on specific designs that combine good light confinement in the gain layer with good spectral control provided by grating structures patterned in silicon.

Silicon Photonics taps on the volume manufacturing capability of traditional silicon manufacturing techniques, to provide dramatic cost reduction for various application domains employing optical communications technology. In addition, an important new application domain would be the implementation of high bandwidth optical interconnects in and around CPUs. Besides volume manufacturability, Silicon Photonics also allows the monolithic integration of multiple optical components on the same wafer to realize highly compact photonic integrated circuits (PICs), in which functional complexity can be increased for little additional cost. An important pre-requisite for Si PICs is a device library in which the devices are compatibly developed around a common SOI platform. A device library comprising passive and active components was built, which includes light guiding components, wavelength-division-multiplexing (WDM) components, switches, carrier-based Si modulators and electro-absorption based Ge/Si modulators, Ge/Si photodiodes and avalanche photodiodes, as well as light emitting devices. By integrating various library devices, PIC test vehicles such as monolithic PON transceivers and DWDM receivers have been demonstrated. A challenge with Si PICs lies with the coupling of light into and out of the sub-micrometer Si waveguides. The mode size mismatch of optical fibers and Si waveguides was addressed by developing a monolithically integrated multi-stage mode converter which offers low loss together with relaxed fiber-to-waveguide alignment tolerances. An active assembly platform using MEMS technology was also developed to actively align and focus light from bonded lasers into waveguides.

In recent years, thin-film photovoltaic companies started realizing their low manufacturing cost potential, and have been grabbing an increasingly larger market share. Copper Indium Gallium Selenide (CIGS) is the most promising thin-film PV material, having demonstrated the highest energy conversion efficiency in both cells and modules. However, most CIGS manufacturers still face the challenge of delivering a reliable and rapid manufacturing process that can scale effectively and deliver on the promise of this material system. HelioVolt has developed a reactive transfer process for CIGS absorber formation that has the benefits of good compositional control, and a fast high-quality CIGS reaction. The reactive transfer process is a two stage CIGS fabrication method. Precursor films are deposited onto substrates and reusable cover plates in the first stage, while in the second stage the CIGS layer is formed by rapid heating with Se confinement. HelioVolt also developed best-in-class packaging technologies that provide unparalleled environmental stability. High quality CIGS films with large grains were fabricated on the production line, and high-performance highreliability monolithic modules with a form factor of 120 cm × 60 cm are being produced at high yield and low cost. With conversion efficiency levels around 14% for cells and 12% for modules, HelioVolt is commercializing the process on its first production line with 20 MW capacity, and is planning its next GW-scale factory.

We present a novel "smart-pixel" able to detect single photons and to measure and record in-pixel the time delay between a START pulse (e.g., laser excitation, cell stimulus, or LIDAR flash) and a STOP pulse given by the detection of a single photon (e. g., fluorescence decay signal or back reflection from an object). This smart-pixel represents the basic building block of SPAD arrays aimed at time-correlated single photon counting (TCSPC) applications (like FLIM, FCS, FRET), but also at photon timing and direct Time-of-Flight (dTOF) measurements for 3D ranging applications (e.g., in LIDAR systems). The pixel comprises a Single-Photon Avalanche Diode (SPAD) detector, an analog sensing and driving electronics, and a Time-to-Digital Converter monolithically designed and manufactured into the same chip. We report on the design and characterization of prototype circuits, fabricated in a 0.35 μm standard CMOS technology containing complete conversion channels, smart-pixels and ancillary electronics with 20 μm active area diameter SPAD detectors and related quenching circuitry. With a 100 MHz reference clock, the TDC provides a time-resolution of 10 ps, a dynamic range of 160 ns and very high conversion linearity.

Three dimensions (3D) acquisition systems are driving applications in many research field. Nowadays 3D acquiring systems are used in a lot of applications, such as cinema industry or in automotive (for active security systems). Depending on the application, systems present different features, for example color sensitivity, bi-dimensional image resolution, distance measurement accuracy and acquisition frame rate. The system we developed acquires 3D movie using indirect Time of Flight (iTOF), starting from phase delay measurement of a sinusoidally modulated light. The system acquires live movie with a frame rate up to 50frame/s in a range distance between 10 cm up to 7.5 m.

We introduce a multi-layer silicon photonic microring resonator filter, fabricated using deposited materials, and transmit up to 12.5-Gb/s error-free data, establishing a novel class of high-performance silicon photonics for advanced photonic NoCs. Furthermore, by leveraging deposited materials, we propose a novel fully-integrated scalable photonic switch architecture for data center networks, sustaining nonblocking 256×256 port size with nanosecond-scale switching times, interconnecting 2,560 server racks with 51.2-Tb/s bisection bandwidth.

We report on our efforts to integrate silica and polymer waveguide devices, such as arrayed waveguide gratings (AWG's), tunable lenses, optical switches, variable optical attenuators (VOA's), power taps. In particular, the realizations of various optical add/drop multiplexers and tunable dispersion compensators are discussed. The integration techniques, the design architectures and the corresponding optical performances are presented.

For about ten years, we have been developing InP on Si devices under different projects focusing first on μlasers then on semicompact lasers. For aiming the integration on a CMOS circuit and for thermal issue, we relied on SiO₂ direct bonding of InP unpatterned materials. After the chemical removal of the InP substrate, the heterostructures lie on top of silicon waveguides of an SOI wafer with a separation of about 100nm. Different lasers or photodetectors have been achieved for off-chip optical communication and for intra-chip optical communication within an optical network. For high performance computing with high speed communication between cores, we developed InP microdisk lasers that are coupled to silicon waveguide and produced 100μW of optical power and that can be directly modulated up to 5G at different wavelengths. The optical network is based on wavelength selective circuits with ring resonators. InGaAs photodetectors are evanescently coupled to the silicon waveguide with an efficiency of 0.8A/W. The fabrication has been demonstrated at 200mm wafer scale in a microelectronics clean room for CMOS compatibility. For off-chip communication, silicon on InP evanescent laser have been realized with an innovative design where the cavity is defined in silicon and the gain localized in the QW of bonded InP hererostructure. The investigated devices operate at continuous wave regime with room temperature threshold current below 100 mA, the side mode suppression ratio is as high as 20dB, and the fibercoupled output power is ~7mW. Direct modulation can be achieved with already 6G operation.

Photonic reservoir computing is a hardware implementation of the concept of reservoir computing which comes from the field of machine learning and artificial neural networks. This concept is very useful for solving all kinds of classification and recognition problems. Examples are time series prediction, speech and image recognition. Reservoir computing often competes with the state-of-the-art. Dedicated photonic hardware would offer advantages in speed and power consumption. We show that a network of coupled semiconductor optical amplifiers can be used as a reservoir by using it on a benchmark isolated words recognition task. The results are comparable to existing software implementations and fabrication tolerances can actually improve the robustness.

The optical amplifier performance of Nd³⁺-doped polymer and amorphous Al₂O₃ channel waveguides with single-mode and multi-mode behavior around 880 nm is compared. Internal net gain in the wavelength range 865-930 nm is investigated under continuous-wave excitation near 800 nm, for Nd³⁺ dopant concentrations typically in the range of 0.6- 1.0 × 10²⁰ cm^-3. A peak gain of 2.8 dB at 873 nm is obtained in a 1.9-cm-long polymer waveguide at a launched pump power of 25 mW. The small-signal gain measured in a 1-cm-long sample is 2.0 dB/cm. In Al₂O₃, a peak gain of 1.57 dB/cm in a short and 3.0 dB in a 4.1-cm-long waveguide is obtained at 880 nm. Tapered multi-mode Nd³⁺-doped amplifiers are embedded into an optical backplane and a maximum 0.21 dB net gain is demonstrated in a structure consisting of an Al₂O₃:Nd³⁺ amplifier placed between two passive polymer waveguides on an optical backplane. The gain can be further enhanced by increasing the pump power and improving the waveguide geometry, and the wavelength of amplification can be adjusted by doping other rare-earth ions.

We report a white-light Mach-Zehnder interferometry method for an accurate measurement of spectral distribution of the chromatic dispersion coefficient of very short optical waveguides over a wavelength range of 1520~1560 nm. The chromatic dispersion curve of a 7.6 mm long silicon nano-waveguide of 400 nm width and 250 nm height was successfully measured by confirming the method with standard single-mode fibers up to 3 cm length, for which its total chromatic dispersion is as small as 0.51 fs/nm. This method will be very useful for determination of chromatic dispersion profile of compact nanowaveguide devices.