An on-chip integrated wavelength demultiplexer designed using an inverse computational algorithm is experimentally demonstrated. 1,300 and 1,550 nm wavelength light is sorted in a device area of just 2.8 × 2.8 μm2.

/pdf/inverse-design-and-demonstration-of-a-compact-and-broadband-1eki081do0.pdf

Inverse design and demonstration of a compact and broadband on-chip wavelength demultiplexer

Silicon-based large-scale photonic integrated circuits are becoming important, due to the need for higher complexity and lower cost for optical transmitters, receivers and optical buffers. In this paper, passive technologies for large-scale photonic integrated circuits are described, including polarization handling, light non-reciprocity and loss reduction. The design rule for polarization beam splitters based on asymmetrical directional couplers is summarized and several novel designs for ultra-short polarization beam splitters are reviewed. A novel concept for realizing a polarization splitter–rotator is presented with a very simple fabrication process. Realization of silicon-based light non-reciprocity devices (e.g., optical isolator), which is very important for transmitters to avoid sensitivity to reflections, is also demonstrated with the help of magneto-optical material by the bonding technology. Low-loss waveguides are another important technology for large-scale photonic integrated circuits. Ultra-low loss optical waveguides are achieved by designing a Si3N4 core with a very high aspect ratio. The loss is reduced further to <0.1 dB m−1 with an improved fabrication process incorporating a high-quality thermal oxide upper cladding by means of wafer bonding. With the developed ultra-low loss Si3N4 optical waveguides, some devices are also demonstrated, including ultra-high-Q ring resonators, low-loss arrayed-waveguide grating (de)multiplexers, and high-extinction-ratio polarizers. Newly developed photonic components could allow large-scale photonic integrated circuits to be built on silicon substrates. Daoxin Dai from Zhejiang University, China, alongside co-workers from the University of California, USA, have proposed several new optical technologies for use in photonic integrated circuits, which substitute or work alongside electrical circuits in optical devices. The researchers have designed new ultrashort polarization-handling devices that split high-intensity beams of light, and a ring optical isolator that reduces reflections. The team have also created a new waveguide based on silicon nitride that can guide optical waves with a minimal loss of energy. These new technologies will allow scientists to construct higher performance, more compact optical devices.

/pdf/passive-technologies-for-future-large-scale-photonic-4doamz9zqi.pdf

Passive technologies for future large-scale photonic integrated circuits on silicon: polarization handling, light non-reciprocity and loss reduction

In this paper, we review the current status of the hybrid silicon photonic integration platform with emphasis on its prospects for increased integration complexity. The hybrid silicon platform is maturing fast as increasingly complex circuits are reported with tens of integrated components including on-chip lasers. It is shown that this platform is well positioned and holds great potential to address future needs for medium-scale photonic integrated circuits.

/pdf/hybrid-silicon-photonic-integrated-circuit-technology-1988farjec.pdf

Hybrid Silicon Photonic Integrated Circuit Technology

Part I. Silicon Photonics - Introduction: 1. Fabless Silicon Photonics: 1.1 Introduction 1.2 Silicon photonics - the next fabless semiconductor industry 1.3 Applications 1.4 Technical challenges and the state of the art 1.5 Opportunities 2. Modelling and Design Approaches: 2.1 Optical Waveguide Mode Solver 2.2 Wave Propagation 2.3 Optoelectronic models 2.4 Microwave Modelling 2.5 Thermal Modelling 2.6 Photonic Circuit Modelling 2.7 Physical Layout 2.8 Software Tools Integration Part II. Silicon Photonics - Passive Components: 3. Optical Materials and Waveguides: 3.1 Silicon-on-Insulator 3.2 Waveguides 3.3 Bent waveguides 3.4 Code Listings 3.5 Problems 4. Fundamental Building Blocks: 4.1 Directional couplers 4.2 Y-Branch 4.3 Mach-Zehnder Interferometer 4.4 Ring resonators 4.5 Waveguide Bragg Grating Filters 4.6 Code Listings 4.7 Problems 5. Optical I/O: 5.1 The challenge of optical coupling to silicon photonic chips 5.2 Grating Coupler 5.3 Edge Coupler 5.4 Polarization 5.5 Code Listings 5.6 Problems Part III. Silicon Photonics - Active Components: 6. Modulators: 6.1 Plasma Dispersion E 6.2 PN Junction Phase Shifter 6.3 Micro-ring Modulators 6.4 Forward-biased PIN Junction 6.5 Active Tuning 6.6 Thermo-Optic Switch 6.7 Code Listings 6.8 Problems 7. Detectors: 7.1 Performance Parameters 7.2 Fabrication 7.3 Types of detectors 7.4 Design Considerations 7.5 Detector modelling 7.5.2 Electronic Simulations 7.6 Code Listings 7.7 Problems 8. Lasers: 8.1 External Lasers 8.2 Laser Modelling 8.3 Co-Packaging 8.4 Hybrid Silicon Lasers 8.5 Monolithic Lasers 8.6 Alternative Light Sources 8.7 Problems Part IV. Silicon Photonics - System Design: 9. Photonic Circuit Modelling: 9.1 Need for photonic circuit modelling 9.2 Components for System Design 9.3 Compact Models 9.4 Directional Coupler - Compact Model 9.5 Ring Modulator - Circuit Model 9.6 Grating Coupler - S Parameters 9.7 Code Listings 10. Tools and Techniques: 10.1 Process Design Kit (PDK) 10.2 Mask Layout 11. Fabrication: 11.1 Fabrication Non-Uniformity 11.2 Problems 12. Testing and Packaging: 12.1 Electrical and Optical Interfacing 12.2 Automated Optical Probe Stations 12.3 Design for Test 13. Silicon Photonic System Example: 13.1 Wavelength Division Multiplexed Transmitter.

Silicon Photonics Design: From Devices to Systems

Five criteria that are usually considered by IEEE standards committees for development of next generation standards are broad market potential, distinct identity, and compatibility, as well as technical and economic feasibility. We consider these criteria separately and show that the new emerging large-volume markets loosely defined as Computercom will demand new standards and new technologies. We discuss how the balance between single-channel bit rate, and number of wavelength multiplexed and spatially multiplexed optical channels can help to satisfy the need for huge total bandwidth, while keeping cost low and power efficiency high. Silicon CMOS-integrated photonics holds promise to become a technology of choice for wide deployment of low-power and cost-effective optical interconnects for these new markets, and to become a single solution addressing distances spanning from just a meter to 10km.

Silicon CMOS-integrated nano-photonics for computer and data communications beyond 100G

The demonstration of a 4λ×10Gbps Silicon Photonics CWDM link integrating all optical components, electronics and packaging technologies required for system integration is reported. Further demonstration of the link operating at 50Gbps, 4λ×12.5Gbps, is also shown.

Demonstration of a High Speed 4-Channel Integrated Silicon Photonics WDM Link with Hybrid Silicon Lasers

A system includes an optical transceiver assembly, including a flip chip connection of a semiconductor die with a photonic transceiver that overhangs a substrate to which it is to be connected. The assembly further includes an alignment pin that is held to the semiconductor die at a micro-engineered structure in the semiconductor die. The alignment pin provides passive alignment of the photonic transceiver with an optical lens that interfaces the photonic transceiver to one or more optical channels.

Optical connection through single assembly overhang flip chip optics die with micro structure alignment

A connection port provides electrical and/or optical interface capability. The combined electrical and optical interface port may include an optical communication light engine within the connection port itself. The connection port includes a connector housing, an electrical interface assembly, and an optical interface assembly incorporated together. One implementation of the optical communication light engine includes a laser diode to generate optical signals, a photo diode to receive optical signals, and an optical integrated circuit (IC) to control optical interface.

Combined Optical and Electrical Interface

Embodiments introduce redundant optical channels to significantly extend the lifetime of parallel optical transceivers. A plurality of transmitters, N, transmit on a plurality of optical channels, where N is an integer number of optical channels greater than 1. One or more redundant channels, M, are also provided. N+M multiple input shift registers provide multiple paths for signals from each of the transmitters to connect to N+M laser diodes. In the event up to M of the N+M laser diodes fail, the multiple input shift registers connect the N transmitters to functioning ones of the N+M laser diodes thus extending the life of the device. A corresponding scheme is also described for the receiver side.

Redundant channel implementation to extend optical transceiver lifetime and reliability

A connection port (120) provides electrical (126) and/or optical (124) interface capability. The combined electrical and optical interface port may include an optical communication light engine (230) within the connection port itself. The connection port includes a connector housing (122), an electrical interface assembly, and an optical interface assembly incorporated together. One implementation of the optical communication light engine (230) includes a laser diode to generate optical signals, a photo diode to receive optical signals, and an optical integrated circuit (IC) to control optical interface.

Simon S. Lee

Papers

Demonstration of a High Speed 4-Channel Integrated Silicon Photonics WDM Link with Hybrid Silicon Lasers

Optical connection through single assembly overhang flip chip optics die with micro structure alignment

Combined Optical and Electrical Interface

Redundant channel implementation to extend optical transceiver lifetime and reliability

Combined optical and eletrical interface