The pace of the development of silicon photonics has quickened since 2004 due to investment by industry and government. Commercial state-of-the-art CMOS silicon-on-insulator (SOI) foundries are now being utilized in a crucial test of 1.55-mum monolithic optoelectronic (OE) integration, a test sponsored by the Defense Advanced Research Projects Agency (DARPA). The preliminary results indicate that the silicon photonics are truly CMOS compatible. RD however, lasing has not yet been attained. The new paradigm for the Si-based photonic and optoelectric integrated circuits is that these chip-scale networks, when suitably designed, will operate at a wavelength anywhere within the broad spectral range of 1.2-100 mum, with cryocooling needed in some cases

The Past, Present, and Future of Silicon Photonics

The silicon chip has been the mainstay of the electronics industry for the last 40 years and has revolutionized the way the world operates. Today, a silicon chip the size of a fingernail contains nearly 1 billion transistors and has the computing power that only a decade ago would take up an entire room of servers. As the relentless pursuit of Moore's law continues, and Internet-based communication continues to grow, the bandwidth demands needed to feed these devices will continue to increase and push the limits of copper-based signaling technologies. These signaling limitations will necessitate optical-based solutions. However, any optical solution must be based on low-cost technologies if it is to be applied to the mass market. Silicon photonics, mainly based on SOI technology, has recently attracted a great deal of attention. Recent advances and breakthroughs in silicon photonic device performance have shown that silicon can be considered a material onto which one can build optical devices. While significant efforts are needed to improve device performance and commercialize these technologies, progress is moving at a rapid rate. More research in the area of integration, both photonic and electronic, is needed. The future is looking bright. Silicon photonics could provide low-cost opto-electronic solutions for applications ranging from telecommunications down to chip-to-chip interconnects, as well as emerging areas such as optical sensing technology and biomedical applications. The ability to utilize existing CMOS infrastructure and manufacture these silicon photonic devices in the same facilities that today produce electronics could enable low-cost optical devices, and in the future, revolutionize optical communications

http://ieeexplore.ieee.org/iel5/6668/34347/01638290.pdf

Silicon photonics

Diffraction characteristics of general dielectric planar (slab) gratings and surface-relief (corrugated) gratings are reviewed. Applications to laser-beam deflection, guidance, modulation, coupling, filtering, wavefront reconstruction, and distributed feedback in the fields of acoustooptics, integrated optics, holography, and spectral analysis are discussed. An exact formulation of the grating diffraction problem without approximations (rigorous coupled-wave theory developed by the authors) is presented. The method of solution is in terms of state variables and this is presented in detail. Then, using a series of fundamental assumptions, this rigorous theory is shown to reduce to the various existing approximate theories in the appropriate limits. The effects of these fundamental assumptions in the approximate theories are quantified and discussed.

Analysis and applications of optical diffraction by gratings

After dominating the electronics industry for decades, silicon is on the verge of becoming the material of choice for the photonics industry: the traditional stronghold of III-V semiconductors. Stimulated by a series of recent breakthroughs and propelled by increasing investments by governments and the private sector, silicon photonics is now the most active discipline within the field of integrated optics. This paper provides an overview of the state of the art in silicon photonics and outlines challenges that must be overcome before large-scale commercialization can occur. In particular, for realization of integration with CMOS very large scale integration (VLSI), silicon photonics must be compatible with the economics of silicon manufacturing and must operate within thermal constraints of VLSI chips. The impact of silicon photonics will reach beyond optical communication-its traditionally anticipated application. Silicon has excellent linear and nonlinear optical properties in the midwave infrared (IR) spectrum. These properties, along with silicon's excellent thermal conductivity and optical damage threshold, open up the possibility for a new class of mid-IR photonic devices

Silicon Photonics

An attractive direction in next-generation information processing is the development of systems employing particles or quasiparticles other than electrons--ideally with low dissipation--as information carriers. One such candidate is the magnon: the quasiparticle associated with the eigen-excitations of magnetic materials known as spin waves. The realization of single-chip all-magnon information systems demands the development of circuits in which magnon currents can be manipulated by magnons themselves. Using a magnonic crystal--an artificial magnetic material--to enhance nonlinear magnon-magnon interactions, we have succeeded in the realization of magnon-by-magnon control, and the development of a magnon transistor. We present a proof of concept three-terminal device fabricated from an electrically insulating magnetic material. We demonstrate that the density of magnons flowing from the transistor's source to its drain can be decreased three orders of magnitude by the injection of magnons into the transistor's gate.

/pdf/magnon-transistor-for-all-magnon-data-processing-18dgl5h4h6.pdf

Magnon transistor for all-magnon data processing

Spin waves in periodic magnetic structures-magnonic crystals

Light beam switching and coupling in a four-port channel waveguide-horn structure has been accomplished using electrooptic modulation of the critical angle of a refractive index interface in a Y -cut LiNbO 3 substrate. The resulting double-pole double-throw switch/coupler is potentially capable of simultaneously providing a combination of desirable characteristics.

Optical channel waveguide switch and coupler using total internal reflection

A new type of photonic crystals is proposed. The new crystals have a forbidden gap in the microwave spectrum of magnetostatic spin waves, and, by analogy with photonic crystals, they are called magnon crystals. Specimens of such crystals were fabricated on the basis of yttrium iron garnet films. The surfaces of ferromagnetic films containing two-dimensional etched hole structures were studied by atomic force and magnetic force mag-netometry. The propagation of spin waves through the magnon crystals was investigated.

Ferromagnetic films with magnon bandgap periodic structures: Magnon crystals

Stimulated emission at bandgap energy of 1.1 eV was observed in a silicon nanostructured pn junction diode using current injection at room temperature. Nonuniform diffusion using spin-on boron dopant mixed with silicon dioxide nanoparticles was used to fabricate the device. The spatial confinement of carriers through such localization structures contributes to the enhancement of the stimulated emission. The experimental results show a drastic increase in the optical power and multiple spectral peaks at wavelengths longer than the main peak of spontaneous emission through various phonon-assisted radiative recombination processes. When the injection current significantly exceeds a threshold, a single peak dominates, exhibiting stimulated emission.

Stimulated emission in a nanostructured silicon pn junction diode using current injection

Theoretical and experimental performances of a robust Si-based spot-size converter (SSC) for efficient coupling between a single-mode fiber and a photonic Si-wire waveguide are reported. The SSC is comprised of cascaded horizontal linear and vertical nonlinear up tapers measured 2.0mm and 86μm in length, respectively, in a silicon-on-insulator substrate. The fine modal field of a Si-wire waveguide, 0.54×0.38μm2 in diameters, was expanded to diameters of 5.1×9.2μm2 with measured net transmission loss of 0.5dB at the wavelength of 1.55μm by the miniature SSC.

Chen S. Tsai

Papers

Spin waves in periodic magnetic structures-magnonic crystals

Optical channel waveguide switch and coupler using total internal reflection

Ferromagnetic films with magnon bandgap periodic structures: Magnon crystals

Stimulated emission in a nanostructured silicon pn junction diode using current injection

A silicon-based spot-size converter between single-mode fibers and Si-wire waveguides using cascaded tapers