This PDF file contains the front matter associated with SPIE Proceedings Volume 6897, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

Recent work on vertically-integrated electro-optic and chalcogenide waveguides is reviewed. By integrating As₂S₃ chalcogenide glass with Ti-diffused lithium-niobate (LiNbO₃) waveguides, we are able to dramatically increase the integration density for this electro-optic waveguide platform. As₂S₃ offers a higher refractive index compared to the LiNbO₃ and consequently enables low-loss, small-bend-radii structures that are crucial for making high density optical circuits. As₂S₃ waveguides are patterned on top of LiNbO₃ waveguides. Adiabatic tapers are used to couple light from the LiNbO₃ waveguide into the As₂S₃ waveguide. Bend radii that are less than a hundred microns are enabled using this approach, compared to LiNbO₃ waveguide bend radii that are typically on the order of a centimeter. The design and fabrication are discussed along with experimental results for s-bend structures.

Compact and efficient spectrometers are of great interest for biological and environmental sensing. In this paper, we describe a new class of spectrometers that work based on diffractive properties of spherical beam volume holograms (SBVHs) and cylindrical beam volume holograms (CBVHs). The hologram in these spectrometers acts as a spectral diversity filter (SDF) that maps different input wavelengths onto different locations in the output plane. The main properties of these holographic SDFs and new techniques for removing the ambiguity between incident wavelength (or the input channel) and incident angle (or the input spatial mode) are discussed. By using CBVHs, we show that the spectral mapping of the input beam can be obtained in one direction and the beam can be independently modified in the perpendicular direction. Using this unique property, we demonstrate a spectral wrapping technique to considerably increase the operation spectral range of spectrometers, without sacrificing their resolution. Finally, it is also shown that by combining CBVHs with a Fabry-Perot interferometer, a true two-dimensional spatial-spectral mapping can be formed, and an ultra-high resolution of 0.2 nm with large spectral bandwidth is demonstrated for this tandem spectrometer.

We propose a novel micro surface plasmon resonance (SPR) sensor system based on polymer materials. The proposed SPR system consists of the incident medium with polymer waveguide and the gold thin film for sensing area. Using a polymer optical waveguide instead of a prism in SPR sensing system offers miniaturization, low cost, and potable sensing capability. The whole device performance was analyzed using the finite-difference time domain method. The optimum gold thickness in the attenuated total reflection mirror of polymer waveguide is around 50 nm and the resonance angle to generate surface plasmon wave is 66 degrees.

We proposed a novel grating design of an out-of-plane coupler with non-uniform duty ratio operating at a wavelength of 1.55 μm for the highly efficient coupling from a waveguide to an optical fiber. In order to evaluate the coupling performance, the diffracted output beam profile and the focusing performance due to the variations of duty ratio configuration were investigated by a 2D Bloch-wave analysis. In addition, a simple fabrication method was proposed to realize the grating by the Near-Field Holographic lithography system with variable aperture unit.

The integration of planar optical components at the chip scale with electronic and microfluidic systems is enabling an increased penetration of optical functionality into systems, and in particular, into highly portable systems. Planar lightwave integrated circuits can enable functions such as optical signal interfaces, optical signal distribution, and optical sensing in a planar platform that leverages microelectronic manufacturing technologies. Key to the realization of these chip scale systems are the design and implementation of thin film optoelectronic materials and devices, heterogeneous integration of components, planar polymer waveguides and waveguiding structures, and optical sensors. The integration of photonic components and subsystems with electronic systems and microfluidics systems are also topics of intense investigation for chip scale system with increasing levels of function. Application areas that are emerging include optical signal interfaces and distribution, as well as chip scale integrated optical sensing systems with applications in medicine and the environment.

We report on fabricating Er_xY_2-xSiO₅ nanocrystals using ErCl₃•6H₂O and YCl₃•6H₂O solutions and Si nanowires grown by VSL method. Use of crystalline host allows incorporation of up to 25 at % Er without clustering and loss of optical activity, and use of Y enables continuous mixing of Er and Y for controlling cooperative upconversion. We obtain a cooperative upconversion coefficients of (2.2±1.1)×10^-18 cm³/s and (5.4±2.7)×10^-18 cm³/s at an Er concentration of 1.2×10²¹ cm^-3 and 2.0×10²¹ cm^-3, respectively. These values are up to 10 times lower at 10 times higher Er concentration than those reported for Er-doped silica, and shows that up to 69 dB/cm gain could be achieved for ultra-compact optical amplification. Also, we report on the deposition of Er_xY_2-xSiO₅ thin film on Si substrate using ion beam sputter deposition. Rapid thermal annealing at 1100°C is enough to form crystal phase the film and activate most of Er³⁺ ions.

Aggregate chip bandwidths in server and high performance computing have exceeding Tb/s, and if present trends are to continue would lead to doubling the number of signal pins in each generation. For high bandwidth switch and server applications, bandwidth requirements could exceed the package pin limit as early as 2012. We defined metrics to compare the performance of electrical and optical interconnects, which includes bandwidth density (Gb/s/mm2/port), media bandwidth*distance product (GHz*m), power consumption (mW/Gb/s/Port), and technology comparison metric (Gb/s/mm2/port * GHz*m/mW/Port). We will show that optical interconnects offer a performance metric improvement factor of greater than 25 over electrical interconnects.

We review a bidirectional optical link scheme for memory-interface applications. A driver-receiver combined optical transceiver (TRx) modules was demonstrated on an optical printed-circuit board (OPCB) platform. To select the bidirectional electric input/output signals, a driver-receiver combined TRx IC with a switching function was designed in 0.18-μm CMOS technology. The TRx IC was integrated with VCSEL/PD chips for optical link in the TRx module. The optical TRx module was assembled on a fiber-embedded OPCB, employing a 90°-bent fiber connector for 90° deflection of light beams between the TRx module and the OPCB. The TRx module and the 90° connector were passively assembled on the OPCB, using ferrule-type guide pins/ holes. Employing these constituent components, the bidirectional optical link between a pair of TRx modules has been successfully demonstrated up to 1.25 Gb/s on the OPCB.

We present our approach to a low-cost, highly scalable opto-electronic integration platform based on a commercial CMOS process. In this talk, we detail the performance of the device library elements and highlight performance trade-offs encountered in monolithically integrating optical and electronic circuits. We describe an opto-electronic integrated circuit (OEIC) design toolkit modeled after the standard electronic design flow, which includes automated design rule checking (DRC) and layout-versus-schematic (LVS) checks covering all types of circuit elements. As an example of integration, we detail the design of a multi-channel transceiver chip with 10 Gbps/channel optical data transmission speed and report on its performance.

Materials and devices.for compact optical amplification in Si photonics is reviewed. In particular, as the requirement for high gain per length together with high refractive index renders traditional oxide-based approach problematic, Er-doping of silicon-rich silicon nitride and erbium silicate nanocrystals are proposed and shown to be promising alternatives. Using such new materials, microdisk resonators and slot waveguides that concentrate the light in a compact volume for high functionality are fabricated and characterized.

Micro-disk resonators were fabricated using Er doped silicon-rich silicon nitride (SRSN:Er). SRSN:Er thin films are fully CMOS-compatible and show efficient Er3+ luminescence pumped off-resonantly via Si nanoclusters. The high refractive index of SRSN (>2.0 at 1.5 μm) allows freedom in designing compact micro-disk resonators. Micro-disks with two different contents of Er (0.2 at.%, 0.02 at.%) with a diameter of 25 μm were fabricated, and characterized using evanescent coupling using tapered fibers. Whispering gallery modes with Q-factors in excess of 13000 were obtained, and FDTD calculations indicate that much higher values should be possible. Finally, we demonstrate excitation of fundamental whispering gallery mode via off-resonant, top-pumping of the SRSN microdisk.

We present a general approach to design temperature-independent high-index-contrast (HIC) waveguides using polymer claddings. Thermal stability has been a significant issue in electronic-photonic integrated circuits because of the heterogeneous heating resulting from integration with electronics. Due to silicons highly temperature-dependent optical properties, athermal performance in silicon-based devices is the critical limitation in device performance. In applications such as wavelength demultiplexing (WDM) and high-resolution spectroscopy, the thermo-optic (TO) effect results in a wavelength shifts and phase shifts in the spectral response peak of each wavelength channel, which limits the wavelength resolution and affects the spectral channel density. Instead of attempting to diminish temperature gradience across the chip, an elegant solution is to design athermal waveguides that are insensitive to ambient temperature. Thermo-optically neutral designs are achieved by choosing a polymer cladding material, whose thermo-optic coefficient is opposite to that of silicon (TO_Si = +1.8×10^-4 K^-1). We present a comprehensive study of temperature dependence in HIC waveguides, using DuPont's polymers as the cladding materials. We provide general design criteria for athermal HIC waveguides by developing analytical and empirical expressions.

The yield of solid state camera modules declines with increasing imager resolution. The easiest means of compensating for this trend is to package the imager die before they are assembled into camera modules. The packaging is preferably accomplished at the wafer level. The package cover is a sheet of glass that forms part of the optical train of the solid state camera. This paper discusses the properties required of the glass and describes a computer model that was constructed to provide quantitative insight into its effect on the optical performance of image sensors. The study corroborates practical measurements that the cover glass has no significant effect on the low light sensitivity of a typical camera module. The cover glass does introduce some reflection losses and minor image aberrations, but these can be managed through the combination of attention to the design of the total optical path and making the cover glass as thin as possible.

We describe a photonic quantum ring (PQR) laser device of three dimensional toroidal whispering gallery cavity. We have succeeded in fabricating the first genuine mega-pixel laser chips via regular semiconductor technology. This has been realized since the present injection laser emitting surface-normal dominant 3D whispering gallery modes (WGMs) can be operated CW with extremely low operating currents (μA-nA per pixel), together with the lasing temperature stabilities well above 140 deg C with minimal redshifts, which solves the well-known integration problems facing the conventional VCSEL. Such properties unusual for quantum well lasers become usual because the active region, involving vertically confining DBR structure in addition to the 2D concave WGM geometry, induces a 'photonic quantum ring (PQR)-like' carrier distribution through a photonic quantum corral effect. A few applications of such mega-pixel PQR chips are explained as follows: (A) Next-generation 3D semiconductor technologies demand a strategy on the inter-chip and intra-chip optical interconnect schemes with a key to the high-density emitter array. (B) Due to mounting traffic problems and fatalities ITS technology today is looking for a revolutionary change in the technology. We will thus outline how 'SLEEP-ITS' can emerge with the PQR's position-sensing capability. (C) We describe a recent PQR 'hole' laser of convex WGM: Mega-pixel PQR 'hole' laser chips are even easier to fabricate than PQR 'mesa' lasers. Genuine Laguerre-Gaussian (LG) beam patterns of PQR holes are very promising for biocell manipulations like sorting mouse myeloid leukemia (M1s) cells. (D) Energy saving and 3D speckle-free POR laser can outdo LEDs in view of red GaAs and blue GaN devices fabricated recently.

We report on the successful design of a silicon micro-ring resonator for improved sensitivity and selectivity in the optical bio-sensing applications. By controlling the waveguide width w, the radius of the resonator R, and the waveguide separation S, we improved the sensitivity and the selectivity of the micro-ring resonator sensor. We obtained the sensitivity of 0.79nm/0.001, which is a 50% increase over the sensitivity without the reduction of the waveguide width. We obtained the selectivity of more than 3,000 with nearly 100% output intensity. We compared these results with the results obtained from the well-established Finite Difference Time Domain (FDTD) method and found that they are in excellent agreement with each other.

All-optical header recognition using a tree-structure is reported for a three-bit address. Each bit of a three bit header is read using an optical Sagnac AND gate and the outcome is used to control each level of the three level tree-structure switch. Traffic at 10 Gb/s (payload) is directed through the switch and each possible address outcome is validated. Reflective semiconductor optical amplifiers (RSOAs) are used as the 1 x 2 space switch at each node of the tree-structure switch. A noise propagation analysis that considers mostly amplified spontaneous emission noise is presented. This analysis takes into account the saturation power of the SOAs, their noise figure, the gain of each SOA and the coupled optical power. It is concluded that large switches based on semiconductor optical amplifiers can be constructed using cascaded SOAs.

The routing of optical signals in metropolitan area networks, core to edge, has seen significant innovations in recent years, fueled by the increased demand for bandwidth in the age of Web 2.0 applications and services. We review the main types of optical routers and describe and contrast their functionalities, attributes, architectures, use in networks, and underlying optoelectronic technologies.

We report the first demonstration of a 10 GHz dual-fiber-loop Opto-Electronic Oscillator (OEO) without RF-amplifiers. Using a recently developed highly efficient RF-Photonic link with RF-to-RF gain facilitated by a high power laser, highly efficient optical modulator and high power phototectectors, we have built an amplifier-less OEO that eliminates the phase noise produced by the electronic amplifier. The dual-loop approach can provide additional gain and reduce unwanted multi-mode spurs. However, we have observed RF phase noise produced by the high power laser include relative intensity noise (RIN) and noise related to the laser's electronic control system. In addition, stimulated Brillouin scattering limits the fiber loop's length to ~2km at the 40mW laser power needed to provide the RF gain which limits the system's quality factor, Q. We have investigated several different methods for solving these problems. One promising technique is the use of a multi-longitudinal-mode laser to carry the RF signal, maintaining the total optical power but reducing the optical power of each mode to eliminate the Brillouin scattering in a longer fiber thereby reducing the phase noise of the RF signal produced by the OEO. This work shows that improvement in photonic components increases the potential for more RF system applications such as an OEO's with higher performance and new capabilities.

We have experimentally demonstrated the transmission performance of a feedforward optical transmitter using an external light injection technique. The feedforward compensation method shows 31 dB intermodulation distortion suppression and 2.2 dB noise reduction. A high side-mode suppression ratio (SMSR) exceeding 35 dB of the wavelength-locked FP-LD was obtained over 12 nm ranges. The suppression characteristics of the intermodulation distortion for wavelength differences and various transmission lengths were measured and analyzed as the evaluation criteria for the transmission performance in WDM/SCM based radio-over-fiber systems.

In this paper, we newly propose an optical triplexer which is one of key components in Gigabit Ethernet Passive Optical Network for Fiber-To-The-Home network. Based on a photonic crystal structure with local point defects, two types of optical triplexers were optimally designed. The size-tuned optical triplexer shows the extinction ratios of -17.8 dB, -14.4 dB, and -15.9 dB for the wavelengths of 1310nm, 1490nm, and 1550 nm, respectively. And the index-tuned optical triplexer shows the extinction ratios of -19.24dB, -17.09dB, and -22.68dB for the wavelengths of 1310nm, 1490nm, and 1550 nm, respectively. The size of the proposed optical triplexers were about 4 × 3 μm².

Portable bio-optical systems have required not only small size but also high sensitive and precise detection technique. To achieve high sensitivity, portable bio-optical systems should be set up to minimize the effects of noises such as Johnson noise, 1/f noise, shot noise etc. In order to reduce the influence from these noises, we have applied a novel lock-in detection technique. The lock-in detection technique is able to effectively suppress these noises as choosing a frequency high enough to avoid 1/f noise and low enough to avoid parasitic noises occurred on high frequency. We use lock-in detection technique with a simple structure - several op-amplifiers and MOSFETs. Using the lock-in scheme, we recovered signals in the presence of overwhelming background noises without applying multistage amplifiers and filters. This technique provides high resolution measurements of relatively clean signals over several orders of magnitude and frequency by compared with conventional detection method. We have demonstrated portable bio-optical system using infrared LED and PD with our hybrid type lock-in detection module.

We reports on an experimental result on a wet chemical etching of silicon for the fabrication of a mold template to be used in the embossing of optical waveguide. The silicon wafers we etched with its sidewall inclined to 45° and vertical to the bottom by using the anisotropic etching characteristics of the crystalline silicon. The results show that the surface roughness of the etched (100) and (110) planes is very much dependent on the etching condition such as the etchant concentration and etching temperature. The etched surface roughness is reduced by about 10 times from 34.5nm to 3.05nm in the (100) plane etching by changing the etching condition from 10M KOH solution at 80°C to 18M KOH solution at 40°C. For the (110) plane, the etched roughness is reduced dramatically from 115.75nm to 9.05nm by changing the etching condition from IPA saturated 5M KOH solution at 80°C to 1.25M KOH at 40°C.