This PDF file contains the front matter associated with SPIE Proceedings Volume 7219, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

We review 10Gb/sec Optical Proximity Communication realized with packaged chips that carry SOI optical waveguides and reflecting mirrors micromachined in silicon. The high precision chip to chip alignment and placement was enabled by a new packaging concept based on the co-integration of pyramidal pit features defined by anisotropic silicon etch and matching high precision micro-spheres. We support this novel packaging approach with measured optical transmission data and discuss the extent of it towards other applications of Proximity Communication.

We review our recent work on chirped waveguide gratings for efficient coupling between standard single mode optical fibers and silicon photonic wire waveguides. The use of a linear chirp in grating period reduces the second order Bragg reflection from the waveguide gratings and increases the coupling efficiency for perfectly vertical optical fibers. Measurement results obtained from devices fabricated using deep UV lithography yielded coupling efficiencies of over 34%. Techniques to further improve the coupling efficiency will be discussed. The use of chirped waveguide gratings for low cost photonic packaging and the application of waveguide gratings for splitting/combining light will also be presented.

Optical link technology will play an increasingly important role for board-level interconnects in servers and supercomputers as a means to keep pace with the increasing intra-system bandwidth requirements. Low-cost and high density optical packaging concepts are required. We describe the development of board-level interconnects based on polymer waveguide technology. In this paper, we focus on flexible optical waveguide sheets and the passive alignment of optical connectors.

The paper describes the research in the £1.3 million IeMRC Integrated Optical and Electronic Interconnect PCB Manufacturing (OPCB) Flagship Project in which 8 companies and 3 universities carry out collaborative research and which was formed and is technically led by the author. The consortium's research is aimed at investigating a range of fabrication techniques, some established and some novel, for fabricating polymer multimode waveguides from several polymers, some formulations of which are being developed within the project. The challenge is to develop low cost waveguide manufacturing techniques compatible with commercial PCB manufacturing and to reduce their alignment cost. The project aims to take the first steps in making this hybrid optical waveguide and electrical copper track printed circuit board disruptive technology widely available by establishing and incorporating waveguide design rules into commercial PCB layout software and transferring the technology for fabricating such boards to a commercial PCB manufacturer. To focus the research the project is designing an optical waveguide backplane to tight realistic constraints, using commercial layout software with the new optical design rules, for a demonstrator into which 4 daughter cards are plugged, each carrying an aggregate of 80 Gb/s data so that each waveguide carries 10 Gb/s.

We report recent progress in the design and fabrication of coupled optical micro-resonators and their applications in realizing compact OEIC devices for optical spectral engineering. By leveraging synthesis techniques for analog and digital electrical circuits, advanced coupled-microring device architectures can be realized with the complexity and functionality approaching that of state-of-the-art microwave filters. In addition, the traveling wave nature of microring resonators can be exploited to realize novel devices not possible with standing wave resonators. Applications of coupledmicro- resonator devices in realizing complex optical transfer functions for amplitude, phase and group delay engineering will be presented. Progress in the practical implementation of these devices in the Silicon-on-Insulator OEIC platform will be highlighted along with the challenges and potential for constructing very high order optical filters using coupledmicroring architectures.

The polysilane optical waveguide fabrications by using photo-bleaching technology with the UV lamp and the UV laser direct drawing technologies are reported. The characteristics of the 1xN optical waveguide splitters and the semiconductor tunable lasers (STLs) with polymer tunable external resonators are presented. An average propagation loss of the straight waveguide was less than 0.7dB/cm at 1550 nm. PDL was measured less than 0.5 dB in the case of 1×8 splitter. The insertion loss of 1×4 splitter patterned by laser drawing method was measured less than 7.5 dB/cm. In the STLs the external resonator consists of a singlemode polysilane waveguide and a Bragg grating filter. The power ratio between main and side modes was over 30 dB. Laser power was measured as 5.6 mW at 70% reflective index of the Bragg grating.

Polysilane waveguides present advantages of ease in processing using photo-bleaching technology for drawing Bragg grating on the polysilane film and a larger thermo-optic (T/O) effect more than silica. In this paper we present the tunable lasers (TLs) composed of the LD module and the optical switch and grating circuits, and those characteristics. The TLs oscillate with the reflected wave at the Bragg grating. The switches and Bragg gratings, which are fabricated on the polysilane waveguide, are used for rough and fine tuning operations. The switches are composed of directional couplers with the thin film metal heaters. A channel selection at each output port is performed by choosing specific heaters. The wavelength fine tuning is performed with T/O effect on the Bragg grating. The laser oscillation with the monolithic optical circuit showed that the oscillation wavelength was 1564.16 nm, laser power was -9 dBm, oscillation bandwidth was less than 0.1 nm and the power ratio between main and side modes was more than 30 dB.

We describe a proposed new class of optonanomechanical integrated photonic devices that can have self-adaptive behavior and self-adaptive optical frequency response, through the use of optical forces to manipulate their movable parts. We propose applications for this technology, and show how such devices can address the enormous dimensional and thermal sensitivity present in nanophotonic structures. Through synthesis of the optomechanical potential, we propose to design and control either the effective optical, or the mechanical, properties of the nanostructure, such as a giant effective optical nonlinear response, nonlinear dynamics and memory. We show device designs that can trap desired states at picometer resolution. We also describe the design of a novel, self-tuning microcavity design whose moving parts adjust in response to light forces alone to always place the resonance at the wavelength of the incident light over a wide wavelength range. This device concept provides an athermal resonator design (temperature-independent resonance frequency), without use of materials with negative thermooptic coefficients. It could also address a major challenge with conventional strong-confinement (high-index-contrast) integrated photonics - their extreme sensitivities - through a self-locking filter bank and optical cross-connect proposal, that in principle can use arbitrarily low power to trim resonant filter passbands to a wavelength channel grid.

Selenide (CIGS) obtained with the unique combination of low-cost solution-based precursor deposition and a reactive transfer printing method. This approach provides reduced capital costs compared to vacuum deposition approaches, low thermal budget, high throughput, control of crystallographic orientation, and very high device quality materials.

In optical storage systems, the demand for fast optoelectronic integrated circuit (OEIC) is dramatically increasing especially for Bluray and HD DVD. A new OEIC for the blue spectral range, which is integrated monolithically using double epitaxial process that is modified BiCMOS process, is presented in this paper. Proposed OEIC is optimized with respect to bandwidth, sensitivity, and noise in order to achieve high S/N ratio. Interdigited photodiode achieves a responsivity of 0.31A/W at blue range corresponding to a quantum efficiency η of 95%, a frequency response of 450MHz and a rising/falling time of 0.578ns. 3dB frequency response of 204MHz and noise of -89.8dBm [1~120MHz @ RBW=30 KHz] are obtained for the fast channel amplifier. for fast tracking and focusing in a stable servo, offset drift at the amplifier output was compensated using voltage of bandgap reference.

We investigate optical characteristics of the ultra-small zero-cell cavities that consist of two, four and three shifted lattice points in square- and triangular-lattice photonic crystal structures. Mode volumes and Q factors of these cavities are systematically studied using three-dimensional finite-difference-time-domain simulation. In particular, an extremely small mode volume of ~0.015 μm³ [~1.5 (λ/2n_slab)³] is obtained in the triangular-lattice three-hole-shifted cavity. In an experiment, we demonstrate optically pumped room-temperature lasing action with a low lasing threshold of ~130 μW in a square-lattice two-hole-shifted cavity. The operation of this ultra-small laser is unambiguously confirmed by the numerical simulation based on the actual fabricated structures.

We review our recent progress on all-optical switching and bistability using ultrahigh-Q photonic crystal nanocavities. We also discuss all-optical logic gate operations. Because photonic crystal nanocavities can strongly confine photons in a small area for a long time, light can efficiently interact with dipoles. As a result, optical nonlinearities occur at a very low input. Optical nonlinearities are essential as regards all-optical switching and bistability, because they dynamically change such material properties as refractive index. We demonstrate all-optical switching at an operating energy of less than 100 fJ, and bistable operation at less than ~100 μW. In addition, these devices are small and so can operate at a reasonably high speed (~100 ps).

In this paper, we report on the latest advances in implementation of the photonic integrated circuits (PICs) required for optical routing. These components include high-speed, high-performance integrated tunable wavelength converters and packet forwarding chips, integrated optical buffers, and integrated mode-locked lasers.

Monolithically-integrated semiconductor optical amplifiers (SOAs) have the potential for enabling high-speed and low-crosstalk optical switches in reconfigurable optical add-drop multiplexers (ROADMs). Using integrated 4x4 switches as the building blocks for large-scale ROADMs, instead of 2x2 switches, will reduce alignment issues and assembly steps during manufacturing. The switch is based on SOAs, quantum well intermixed (QWI) passive 1x4 MMI splitters/combiners, and total internal reflection mirrors. We present the results of the 4x4 switch design, for a switch of 5.3 mm x 3.5 mm in size, with estimated total excess on-chip losses of 23 dB.

We review our work developing label-free molecular sensors using silicon nanophotonic waveguides. We show that the high index contrast of these waveguides provides high surface sensitivity and enables compact sensor designs to be realized. We also describe new waveguide circuit geometries that allow photonic wire waveguide sensors to be conveniently arrayed in two dimensions for compatibility with commercial spotting tools, while simultaneously providing long interaction length and improved molecular capture efficiency. These sensor designs are shown to provide a practical route to the development of label-free, microarrayed biochips for multiparameter analysis.

Recently, a number of portable biosensors have been developed to check the health condition of human beings regardless of time and place. Though those sensors have a merit of a handy one, the signals are inevitably measured with intensive background noises. In order to detect a weak signal concealed in intensive background noises such as Johnson noise, 1/f noise, and shot noise, a special technique is essentially required. As of a special technique, the lock-in detection method is able to minimize the effects of these noises using modulated signal and reference signals. Previously, we applied the lock-in detection method to infrared detection system. The sensitivity of this system was decided by the 1/f noise at the photodetector. In this work, we have demonstrated the portable bio-sensor system using high frequency infrared laser diode and photodetector. Therefore, the main signal of interest may keep away from the effect of the 1/f noise with hybrid-type highly sensitive lock-in detection module. This technique provides the minimum detection range of 3 mV and the dynamic range of 25.8 dB at the noise level of 120 mV.

In this paper we present an optoelectronic integrated circuit (OEIC) based on monolithic integration of organic lightemitting diodes (OLEDs) and CMOS technology. By the use of integrated circuits, photodetectors and highly efficient OLEDs on the same silicon chip, novel OEICs with combined sensors and actuating elements can be realized. The OLEDs are directly deposited on the CMOS top metal. The metal layer serves as OLED bottom electrode and determines the bright area. Furthermore, the area below the OLED electrodes can be used for integrated circuits. The monolithic integration of actuators, sensors and electronics on a common silicon substrate brings significant advantages in most sensory applications. The developed OEIC combines three different types of sensors: a reflective sensor, a color sensor and a particle flow sensor and is configured with an orange (597nm) emitting p-i-n OLED. We describe the architecture of such a monolithic OEIC and demonstrate a method to determine the velocity of a fluid being conveyed pneumatically in a transparent capillary. The integrated OLEDs illuminate the capillary with the flowing fluid. The fluid has a random reflection profile. Depending on the velocity and a random contrast difference, more or less light is reflected back to the substrate. The integrated photodiodes located at different fixed points detect the reflected light and using crosscorrelation, the velocity is calculated from the time in which contrast differences move over a fixed distance.

We report on the designing an optical modulator using photonic crystal (PhC) Mach-Zehnder interferometer (MZI) structure. Typical modulators use MZI structure, where the length of the device stretches up to several millimeters because the electro-optical effect of silicon is very small. We find that the group index of the PhC waveguide can be changed by changing the refractive index of the PhC air holes by filling in the air holes with electro-optic polymer materials. The change of the refractive index of the polymer in the hole by 0.005 induces the change of the group index of the PhC waveguide by up to 0.2. We find that the group index increases, when the wavelength and the radius of the electro-optic polymer hole increases and when the refractive index of electro-optic polymer hole decreases. We find that the group index increases when the length increases and that the group velocity and propagation loss depend on the length of the photonic crystal waveguide due to the finite length of the photonic crystal waveguide. Using all of these findings, we could obtain higher electro-optical effect, which reduces the length of the device into micron scale. When we apply the voltage, we can change the phase difference by π due to the electro-optical effect of the polymer. Our calculation shows the extinction ratio between 35 to 45 dB, dependence of length of the device.

We report on the fabrication and characterization of a residual layer resulting from UV imprinting of singlemode optical waveguide. We have measured the residual thickness formed from the imprinting process for several-um-size singlemode waveguide fabrication using the parameters of the imprinting pressure, dropped volume, and viscosity of the used polymer. We found that the residual layer thickness is dependent on both the initial polymer volume and process pressure and the initial polymer volume is more critical than process pressure. Viscosity of polymer also affects the residual layer thickness, the lowest residual layer thickness of 29nm is achieved with nano-imprinting resin, 0.3uL volume, and imprint pressure more than 20bar. Even with optical resin, the residual layer thickness of 60nm is achieved with 0.3uL volume and imprinting pressure of 30bar.

OEICs for the advanced optical storage systems are required to be compatible with three kinds of disk systems, CD (λ=780nm), DVD (λ=650nm) and bluray disk (λ=405nm). In this paper we present a triple wavelength OEIC with improved isolation areas between adjacent photodiodes, which minimize the dark areas for 405nm laser beam and also improve the effective photodiode areas for 650nm and 780nm laser beams. The isolation area is made not with pwell and pbur layer but with floated p+ for increasing the resistance between adjacent photodiodes. The IC was developed in 0.6um BiCMOS technology with integrated N+ finger type photodiodes. A 3-dB frequency response of 163MHz and a sensitivity of 22mV/uW at the blue laser spectral range (405nm) have been measured. A power consumption of 115mW at 5V supply is low enough for the commercial bluray pickup unit, and a chip area of 2.88mm2 is achieved. We have got good jitter performance of 6.8% at the commercial bluray systems.

Power management is one of the most important issues in portable electronics like cell phone, PDA, UMPC, GPS, MP3 player and laptop computer. Ambient Light Sensors are getting popular as a most effective solution to extend battery lifetime for these devices. This paper provides basic information about ambient light sensors on a general level and introduces an ultra low-power ambient light sensor for portable electronics. The implemented ambient light sensor converts light illuminance to 5-digital codes every 300ms which can measure illuminance from 10 to 1000 Lux consuming only 5uA. An IR-reject optical filter and a built-in integrating analog-to-digital converter reduce influences of infrared ray and 50Hz/60Hz noise from artificial light sources respectively. The ambient light sensor is fabricated in a standard CMOS 0.5-um process technology. Test results show that the implemented ambient light sensor has incandescent/fluorescent light sensitivity ratio around 2.3.

Mode size adapters that are needed to interconnect two planar waveguides of different sizes have been designed and fabricated by the imprinting lithography. Optimum dimensions of the adapters were determined by simulation. The input port of the mode size adapters has fixed cross section size of 10 μm wide and 7 μm height. From the simulation results, the output port should have the lowest optical loss at 5μm in height and 8μm in width. Molds for the imprint were prepared by noble hybrid imprint lithography which employed both imprinting and photolithography and fabrication of mode size adapters with smooth and sloped taper region was successfully demonstrated.