This PDF file contains the front matter associated with SPIE Proceedings Volume 7605, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

We present a design concept for an optimized surface-emitting two-dimensional second-order feedback structure consisting of an array of holes within a dielectric material surrounded by a mirror rim. The mirror rim consists of a first order photonic crystal structure. The lasing properties of such feedback structures with organic gain material are investigated theoretically and experimentally.

In this communication, we report some new results obtained in our laboratories in design, fabrication and characterization of silicon-based optical structures and devices, including metamaterials, raman light amplifiers, and biomatter-silicon interfaces for sensors and biochips.

System-in-package technology is announced as one of the key technologies, which enables the continued increase in functional density and decrease in cost per function required to maintain the progress of electronics by utilizing 3D through innovation in packaging and interconnect technology. A key bottleneck to the realization of high-performance microelectronic systems is the lack of low latency, high-bandwidth, and high density off-chip interconnects. Photonics could overcome these challenges and leverage low-latency and high bandwidth communication within next generation architectures. In this paper state-of-the-art approaches will be discussed and the requirements in 3D integration perspective of converging platforms will be addressed.

Low-cost planar lightwave circuits based on optical polymer waveguide devices hold promise for the next generation of optical communication systems. Over the years, we have put significant effort to exploring the many unique properties of polymer for the realization of new functional optical devices. For example, we have demonstrated several basic polarization-insensitive waveguide devices, where the stress and geometry effects in polymer thin films are balanced through careful waveguide design and thermal tuning. Using a long-period waveguide grating as the basic structure, we have developed a range of broadband filters and add/drop multiplexers, where the large thermooptic coefficient of polymer together with the high temperature sensitivity of the grating design allows an exceedingly wide wavelength range to be tuned thermally. Using vertical optical couplers as building blocks, we have successfully fabricated compact polarization splitters, optical switches, dynamic power splitters, etc. Our other demonstrated devices include waveguide junction splitters and optical interleavers. Recently, we have proposed a new bottom-heating approach for the realization of thermooptic waveguide devices, which can minimize the possibility of damaging the polymer waveguide due to electrode deposition and facilitate electric wiring and device packaging. This paper presents a review of these research activities.

Polymer optical chip containing a combination of 45°-angled cut waveguide, Y-splitter and S-bend structures was designed and fabricated for simple and reliable evaluation of multi-mode waveguides. Effect of mode scramblers was investigated as an appropriate input condition for standardization of measurement of optical characteristics of multi-mode waveguides.

We summarize our recent work on integrated silicon photonics for applications in on-chip optical interconnects and telecommunications, including high performance germanium detectors and a multi-channel receiver, a compact and low power on-chip photonic link, an integrated diplexer and a coherent receiver.

PIN photodiodes are semiconductor devices widely used in a huge range of applications, such as photoconductors, charge-coupled devices, and pulse oximeters. The possibility to combine and to integrate the fabrication of the sensor with its signal conditioning circuitry in a CMOS process flow opens the window to device miniaturization enhancing its properties and lowering the production and assembly costs. This paper presents the design and characterization of silicon based PIN photodiodes integrated in a CMOS commercial process. A high-resistivity, low impurity float zone substrate is chosen as the start material for the PIN photodiode array fabrication in order to fabricate devices with a minimum dark current. The photodiodes in the array are isolated by a guard ring consisting of a n⁺-p⁺ diffusions. However, the introduction of the guard ring design, necessary for photodiode-to-photodiode isolation, leads to an increase of the photodiodes dark current. In this article, the new parasitic term on the dark current is identified, formulated, modelled and experimental proven and has finally been used for an accurate design of the guard ring.

To investigate quantum-confinement (QC) effects on silicon (Si) light source electroluminescence (EL) properties like external power efficiency (EPE) and spectral emission, nanometer-scale Si finger junctions were manufactured in a fully customized silicon-on-insulator (SOI) production technology. All spectrometer-measured thickness-confined SOI light sources displayed pronounced optical power for 600 nm < λ < 1 μm. The best thickness-confined SOI light source emitted about 24 times more optical power around λ = 844 nm and exhibited an EPE improvement factor of about 21 compared to a 350 nm bulk-CMOS avalanche reference light-source operating at the same current. Internal quantum efficiency (IQE) enhancements factors of about 3.5 were attributed to carrier-confinement. The punch-through (PT) technique, which introduced breakdown voltages as low as 6 V, increased the SOI light source EPE by about a factor 2.5. It was estimated that geometric-optical improvement techniques that include Si finger surface profiling, raised the SOI light source external quantum efficiency (EQE) by about a factor 1.7. It was further shown that the SOI Si handle could be used to reflect up to about 40 % of light that would otherwise be lost due to downward radiation back up, thereby increasing the EPE of SOI light sources.

We demonstrate chemical/biological sensor arrays based on high quality factor evanescent microring waveguide resonators in a process that is compatible with CMOS fabrication, glass microfluidic integration, and robust surface chemistry ligand attachment. We cancel out any fluctuations due to liquid temperature variations through a differential dual sensor design. Using laser locking servo techniques we attain detection sensitivities in the ng/ml range. This combination of silicon photonic sensors, robust packaging, high sensitivity and arrayed design is capable of providing a platform for multiplexed chem-bio sensing of molecules suspended in solution.

We developed a new type of optical lens device that can change its curvature like crystalline lens in human eye. The curvature changing capability of the lens allows for a tremendous tuning range in its optical power and subsequently enables miniaturized imaging systems that can perform autofocus, optical zoom, and other advanced functions. In this paper, we study the physical properties of bio-inspired fluidic lenses and demonstrate the optical functionality through miniaturized optical systems constructed with such lenses. We report an auto-focusing optical system that can turn from a camera to a microscope, and demonstrate more than 4X optical zoom with a very short total track length. Finally, we demonstrate the benefits of fluidic lens zoom camera through minimally invasive gallbladder removal surgery.

Our goal is to develop a rectifying antenna (rectenna) applicable to solar spectrum energy harvesting. In particular, we aim to demonstrate viable techniques for converting portion of the solar spectrum not efficiently converted to electric power by current photovoltaic approaches. Novel design guidelines are suggested for rectifying antenna coupled tunneling diodes. We propose a new geometric field enhancement scheme in antenna coupled tunneling diodes that uses surface plasmon resonances. For this purpose, we have successfully implemented a planar tunneling diode with polysilion/SiO₂/polysilcon structure. An antenna coupled asymmetric tunneling diode is developed with a pointed triangle electrode for geometric field enhancement. The geometrically asymmetric tunneling diode shows a unique asymmetric tunneling current versus voltage characteristic. Through comparison with crossover tunneling diodes, we verified that the current asymmetry is not from the work function difference between the two electrodes. Results of RF rectification tests using the asymmetric diode demonstrate that our approach is practical for energy harvesting application. Furthermore, we describe how surface plasmons can enhance the electric field across the tunnel junction, lowering the effective "turn-on" voltage of the diode, further improving rectification efficiency.

We describe the design, development and manufacture of solar power panels based on photovoltaic integrated circuits (PVICs) with high-quality high-uniformity Copper Indium Gallium Selenide (CIGS) thin films produced with the unique combination of low-cost ink-based and physical vapor deposition (PVD) based nanoengineered precursor thin films and a reactive transfer printing method. Reactive transfer is a two-stage process relying on chemical reaction between two separate precursor films to form CIGS, one deposited on the substrate and the other on a printing plate in the first stage. In the second stage, these precursors are brought into intimate contact and rapidly reacted under pressure in the presence of an electrostatic field while heat is applied. The use of two independent thin films provides the benefits of independent composition and flexible deposition technique optimization, and eliminates pre-reaction prior to the synthesis of CIGS. High quality CIGS with large grains on the order of several microns, and of preferred crystallographic orientation, are formed in just several minutes based on compositional and structural analysis by XRF, SIMS, SEM and XRD. Cell efficiencies of 14% and module efficiencies of 12% have been achieved using this method. When atmospheric pressure deposition of inks is utilized for the precursor films, the approach additionally provides lower energy consumption, higher throughput, and further reduced capital equipment cost with higher uptime.

We discuss the enhancement of nonlinear functionalities in slow light photonic crystals. We show how slow light in photonic crystals is created, how nonlinear effects scale with the slowdown factor and what limits nonlinear effects in photonic crystals. We review some of the work recently reported in nonlinear optics in slow light photonic crystals and compare the observed effects to those found in other structures such as coupled resonators or photonic nanowires.

Quantum dot (QD) devices are a promising technology for high operating temperature detectors. We have studied InAs QDs embedded in an InGaAs/InAlAs quantum well structure on InP substrate for middle wavelength infrared detectors and focal plane arrays (FPAs). This combined dot-well structure has weak dot confinement of carriers, and as a result, the device behavior differs significantly from that in more common dot systems with stronger confinement. We report on our studies of the energy levels in the QDWIP devices and on QD-based detectors operating at high temperature with D* over 10¹⁰ cmHz^1/2/W at 150 K operating temperature and high quantum efficiency over 50%. FPAs have been demonstrated operating at up to 200 K. We also studied two methods of adapting the QDWIP device to better accommodate FPA readout circuit limitations.

ZnO-based thin films and nanostructures grown by PLD for various emerging optoelectronic applications. AZO thin films are currently displacing ITO for many TCO applications due to recent improvements in attainable AZO conductivity combined with processing, cost and toxicity advantages. Advances in the channel mobilities and Id on/off ratios in ZnO-based TTFTs have opened up the potential for use as a replacement for a-Si in AM-OLED and AM-LCD screens. Angular-dependent specular reflection measurements of self-forming, moth-eye-like, nanostructure arrays grown by PLD were seen to have <0.5% reflectivity over the whole visible spectrum for angles of incidence between 10 and 60 degrees. Such nanostructures may be useful for applications such as AR coatings on solar cells. Compliant ZnO layers on mismatched/amorphous substrates were shown to have potential for MOVPE regrowth of GaN. This approach could be used as a means to facilitate lift-off of GaN-based LEDs from insulating sapphire substrates and could allow the growth of InGaN-based solar cells on cheap substrates. The green gap in InGaN-based LEDs was combated by substituting low Ts PLD n-ZnO for MOCVD n-GaN in inverted hybrid heterojunctions. This approach maintained the integrity of the InGaN MQWs and gave LEDs with green emission at just over 510 nm. Hybrid n-ZnO/p-GaN heterojunctions were also seen to have the potential for UV (375 nm) EL, characteristic of ZnO NBE emission. This suggests that there was significant hole injection into the ZnO and that such LEDs could profit from the relatively high exciton binding energy of ZnO.

The aim of this work was to demonstrate the fabrication and characterization of erbium-doped optical waveguide amplifiers in X-cut Y-propagating lithium niobate (LiNbO₃) by erbium (Er) and titanium (Ti) co-diffusion. Optical small-signal internal gains up to +0.6 dB/cm at 1531 nm were measured for the transverse electric (TE) and magnetic (TM) modes by optical pumping at 1488 nm with a coupled optical pump power of 95 mW in four different optical waveguide amplifier lengths. The Er and Ti co-diffusion process has shown adequate internal gain efficiency in dB/mW and a beneficial path for the development of LiNbO₃-based integrated optical devices.

Erbium-doped aluminum oxide channel waveguides were fabricated on silicon substrates and their characteristics were investigated for Er concentrations ranging from 0.27 to 4.2 × 10²⁰ cm^-3. Background losses below 0.3 dB/cm at 1320 nm were measured. For optimum Er concentrations in the range of 1 to 2 × 10²⁰ cm^-3, internal net gain was obtained over a wavelength range of 80 nm (1500-1580 nm) and a peak gain of 2.0 dB/cm was measured at 1533 nm. Integrated Al₂O₃:Er³⁺ channel waveguide ring lasers were realized based on such waveguides. Output powers of up to 9.5 μW and slope efficiencies of up to 0.11 % were measured. Lasing was observed for a threshold diode-pump power as low as 6.4 mW. Wavelength selection in the range 1530 to 1557 nm was demonstrated by varying the length of the output coupler from the ring.

Based on the effects of photonic transitions, we show that a linear, broadband and nonreciprocal on-chip optical isolation can be accomplished by dynamic refractive index modulations. Such scheme allows for on-chip optical isolation using standard CMOS fabrication process. We also show how to use photonic transition to create on-chip tunable resonance with quality factor and resonant separately controllable.

An analysis revealing a simple closed form solution for the poles of a polarization-coupled ring resonator is presented for the first time. The resonant frequencies are easily calculated as well as the pole magnitudes based on the relative phase and polarization-dependent ring coupling. Applications include wavelength-division multiplexing (WDM) filters with new pole magnitude tuning capability and analysis of polarization dependence in birefringent fiber-based and integrated-optic resonator-enhanced filters.

We review our recent work on silicon photonic devices for on-chip optical interconnects and optofluidics. On the optical interconnects front, we demonstrate coupled-resonator optical waveguides with gapless inter-cavity coupling for on-chip wide-bandwidth high-order optical channel filters and optical delay lines. We propose a 5×5 matrix switch comprising two-dimensionally cascaded microring resonator-based electrooptic switches for network-on-chip applications and demonstrate a 2×2 matrix switch as a proof-of-concept. We demonstrate cavity-enhanced photocurrent generation in a p-i-n diode embedded microring resonator for wavelength-selective photodetection and monitoring on-chip optical networks. We also investigate a serial-cascaded double-microring-based silicon photonic circuit for high-speed on-chip clock-recovery applications. On the optofluidics front, we study silicon nitride based waveguides with integrated microfluidic channels for optical manipulation of microparticles.

Integration of microspheres inside micro-capillaries or hollow waveguides may allow development of compact focusing tools for a variety of biomedical and photonics applications. However, problems associated with developing focusing microprobes involve the multimodal structure of noncollimated beams delivered by fibers and waveguides. By using numerical ray tracing, it is shown that serial spherical microlenses filter out spatially periodic modes which can be used for obtaining tightly focused beams. Experimental studies are performed for spheres with sizes from 10 to 300 μm with different indices of refraction ranging from 1.47 to 1.9. The chains were assembled inside plastic tubing with bore sizes matching the size of the spheres. By using high index spheres, it is demonstrated that these structures are capable of focusing light in contact with tissue. The beam attenuation properties of such chains are found to be in good agreement with numerical modeling results. Potential applications of integrated microsphere arrays include ultra-precise intraocular and neurosurgical laser procedures, photoporation of cells, and coupling of light into photonic microstructures.

Photonic crystals (PCs) are recently fabricated by the Nano Imprint Lithography (NIL) on the polymers with low indexes because of the simple and short process time and ease of precise manufacturing. But, PCs require high dimensional accuracy due to their optical characteristics. The dimensional accuracy of PCs using NIL depends on the stamp. NIL stamps are usually fabricated by EBL, lift off and etching process. The damage of PC structures happens during the lift off process due to the tearing and ripping problem. So, we report on novel fabrication of NIL stamp using PMGI/PMMA bi-layer lift off technique. We can control the extent of the undercut in the support layer through independent development of PMGI and PMMA. We simulate the band structure of a triangle lattice with a polymer refractive index of 1.495. From the simulation results, we derive that dimensional accuracy of PCs should be maintained below ±30 nm. We make the original pattern by EBL. An optimal dose for achieving this dimension on the PMMA is determined by experiment and has 110 μC/cm² at the aperture 10 μm and EHT 20 kV. To establish optimal process condition, development for PMMA and PMGI is performed according to development time. Then, we deposit the Ni layer using e-beam evaporator and perform the lift off process. We can obtain the PCs structure of Ni metal layer with 70 nm undercut at the optimal development condition. The fabricated PCs structure has dimensional accuracy below 5 nm. These values are sufficient for meeting with optical characteristics of PCs.

This paper reports demonstration of a new simple white-light interferometry method for continuous dispersion curves of the thermo-optic (TO) coefficients of optical samples. Phase shifts of the interference spectra of the white-light interferometer output are measured by changing temperature of an optical sample located in the one of the interferometer arms. A continuous dispersion curve of the TO coefficient of the sample materials over the full wavelength coverage region of the white light beam is obtained from the phase shift information with the temperature change. This new method is tested with a fused silica glass material of well-known optical properties to prove its accuracy by comparing the measured results with its known TO coefficient values. This continuous dispersion information of the TO coefficients of new optical materials will be useful for fabrication of the WDM signal processing devices or functional devices in multi-wavelengths.

As the demands for the higher data transmission capacity and speed as well as higher integration density grow throughout the network, much works have being done in order to integrate the Electrical PCB with Optical PCB. In this paper, among the key technologies to integrate the Electrical PCB with Optical, the technology for getting the via interconnection line with low resistivity using pulse mode electroplating method and bonding technology for high bonding strength with low temperature process are studied. As a result of this study, the measured value of electrical resistivity shows with a range from 20 to 26 mΩ and the PCB bonding technology with high bonding strength is demonstrated with the value of bonding strength from 7 to 8 MPa.