The research and development of organic materials for use in optical components and devices aims to take advantage of several unique properties of these materials, including their stability, tailorability, and flexibility. In this study, by carefully controlling the components, we have developed a material that offers significant advantages over common optical materials. Specifically, the new material has a high refractive index and is curable with ultraviolet (UV) light, solvent free, and transparent over a wide wavelength range. We applied the material to a substrate via spin coating, although other application methods are possible. The production of optical components through press-patterning has received a large amount of attention. The low cost of replication and high throughput of the process provide the potential for low-cost optical components. Typically a metallic plate is patterned via electroplating or electroforming to produce a negative image on the plate. This plate is then pressed into the patternable material and subsequently treated to form the desired pattern in the organic material. Here we report our initial attempts at press-patterning structures into a UV-curable high refractive index material.

A key parameter for the choice of an erbium-doped material suitable for efficient amplification around 1.55 μm is its ability to isolate Er ions from each other in order to increase the quenching concentration and henceforth to improve pumping efficiency. Encapsulation of Er ions by organic ligands results in quenching concentrations about a few % in a polymer matrix and may therefore induce high gain values at 1.55 μm. In this paper, we report on the elaboration and optical characterization of Erbium complex-doped PMMA thin films and waveguides with different concentrations by spin-coating technique. Refractive index of these thin films and etching conditions for waveguide fabrication are carefully investigated. Strong gain coefficient values (up to 9 cm^-1) measured by Amplified Spontaneous Emission are reported at 1.55 μm under 980 nm cw pumping of an erbium-complex-doped PMMA film. A multifunctional polymer material containing an erbium complex together with an electric-field oriented nonlinear optical (NLO) chromophore is shown to simultaneously display good IR gain properties and quadratic NLO response, then qualifying this approach for in-situ amplification of active electro-optic devices for optical signal processing. Rib waveguides made of erbium-doped PMMA have been elaborated using standard lithographic and reactive ionic etching techniques. Gain and loss measurements of these waveguides are characterized for single mode propagation of signal (1.55 μm) and pump (980 nm) waves, and compared to predictions from beam propagation method modelization.

A fast, non-interferometric measurement technique that allows the frequency-dependent delay and amplitude responses to be measured is presented. For a single amplitude and relative phase measurement at a fixed optical wavelength, the measurement time is on the order of a microsecond. RF modulation up to 2.7 GHz can be accommodated. A modified technique using frequency modulation is described to overcome non-idealities in the phase measurement. Results are presented for a fiber Bragg grating and an acetylene gas cell with swept-wavelength laser tuning at a rate of 40 nm/s.

Continued exponential improvements in computational resources bring new opportunities and challenges for photonics modeling. In particular, widely available and inexpensive computer clusters are making a dramatic impact by allowing larger simulation volumes to be computed faster. The growth in accessible computing power is driving a trend towards the most exact modeling techniques which can address an increasing range of applications in integrated optics, and allow designers to take advantage of state-of-the-art manufacturing technology. We demonstrate how this opportunity can be exploited in the area of photonic integration to rigorously simulate three-dimensional devices by FDTD previously thought to be intractable. For example, large-volume, hybrid devices composed of both dielectrics and metals with sub-wavelength structure can now be simulated. Moreover, simulations can include realistic manufacturing imperfections. This allows designers to create and optimize robust devices that are resistant to the imperfections introduced by viable, cost-effective manufacturing.

We present a theoretical study of the dispersion relation of surface plasmon resonances of mesoscopic metal-dielectric-metal microspheres. These are spherically symmetric Bragg resonators comprising thin, alternating layers of dielectric and metal shells around spherical metal cores. By analyzing the solutions to Maxwell's equations, we obtain a simple geometric condition for which the system exhibits a band of surface plasmon modes whose resonant frequencies are weakly dependent on the multipole number. Using a modified Mie calculation, we investigate the effect of this flat-dispersion band on the absorption and scattering cross-sections of the layered particle. We find that a large number of modes belonging to this band can be excited simultaneously by a plane wave, thus enhancing the absorption cross-section. Moreover, we observe a narrow transmission resonance due to the metallodielectric shells behaving as a transparent coating in a narrow spectral range. We demonstrate that the enhanced absorption and transmission of the sphere are geometrically tunable over the entire visible range.

We demonstrate the existence of a bound optical mode supported by an air slot in a thin metallic film deposited on a substrate, with slot dimensions much smaller than the wavelength. The modal size is almost completely dominated by the near field of the slot. Consequently, the size is very small compared with the wavelength, even when the dispersion relation of the mode approaches the light line of the surrounding media. In addition, the group velocity of this mode is close to the speed of light in the substrate, and its propagation length is tens of microns at the optical communication wavelength. We also investigate the performance of bends and power splitters in plasmonic slot waveguides. We show that, even though the waveguides are lossy, bends and splitters with no additional loss can be designed over a wavelength range that extends from DC to near-infrared, when the bend and splitter dimensions are much smaller than the propagation length of the optical mode. We account for this effect with an effective characteristic impedance model based upon the real dispersion relation of the plasmonic waveguide structures.

The objective of this paper is to present MEMS-tunable leaky-mode resonance elements. With focus on the silicon-oninsulator (SOI) materials system, the paper provides computed results elucidating the nature of resonant leaky modes associated with periodic refractive-index lattices such as gratings and photonic crystals. Introductory examples demonstrate the general features of the basic guided-mode resonance effect and the resulting externally measurable diffraction efficiency. Computed Brillouin diagrams illustrate the association of the guided-mode resonance with the second stopband considering grating profile symmetry and its Fourier harmonic content controlled by the chosen fill factors. A tunable double-grating resonant leaky-mode MEMS-type element is then introduced. Significant level of tunability is demonstrated by controlling the effective fill factor and the structural symmetry as well as the effective thickness of the resonant layer. For a particular example SOI structure treated, it is shown that the resonance wavelength can be shifted by ~500 nm with a horizontal movement of ~300 nm within the 1.6-2.2 μm wavelength band. Additionally, the reflectance can be tuned from ~10^-4 to 100% with a vertical movement of ~250 nm. These results demonstrate potentially new dimensions in design of tunable optical devices.

Couplers based on the multimode interference (MMI) principle form the basis for a variety of integrated optics devices that can achieve routing, switching and other telecommunication functions. Whilst small order MMI couplers show good performance, the imaging properties deteriorate as the order increases. In order to better understand the performance capabilities of these devices there is interest in devising improved analytical models of MMI structures. This paper reviews various approaches to modeling integrated optics devices based on MMI couplers and attempts to highlight the advantages and the pitfalls associated with a number of models, and suggests some avenues for improving these models.

A waveguide surface plasmon resonance (SPR) optical sensor based on wavelength modulation is presented. Strip waveguides are fabricated using MicroChem's SU-8 photoresist via UV lithography. Next, a bimetallic silver-gold film is deposited on the waveguides for exciting surface plasmon resonance. The underlying silver yields better evanescent field enhancement of the sensing surface, while the overlying gold ensures that the stability of the metallic film is not compromised. Experiments were conducted using various glucose concentrations as the analyte, and the normalized transmission output of the waveguide shows a good SPR curve for all the analytes. With a better evanescent field extension, the proposed waveguide SPR configuration extends the use of SPR, especially in bio-sensing, as longer ligands can be immobilized and bigger analytes can be monitored.

We report two novel kinds of LiNbO3 electro-optic modulators. The first one is oriented toward long haul high bit rate telecommunication systems. An original single-ended structure with a poled section and phase reversal electrodes is proposed to prevent the intensity modulation from chirp, without sacrifice on the driving voltage. We also show that improvements can be performed with the use of several poled sections. To remain attracting, LiNbO3 modulators should also exhibit a lower size. The second configuration described here is a new generation of LiNbO3 modulators based on photonic crystals, with a micrometric active length. We theoretically show that the optimal photonic structures for an efficient electro-optical tuning are based on a triangular array of holes integrated on a X-cut substrate. The first optical characterizations confirm the theoretical predictions, and exhibit a -12dB extinction ratio in the transmission response.

Silicon oxynitride optical waveguides with a grating coupler were used for a label-free detection approach that measures the change of refractive index at the grating surface. Two approaches were used for the grating fabrication: (i) commercially available linear gratings were used as stamps for imprint lithography and the pattern was transferred by dry-etching; (ii) polystyrene microspheres self-assembly in an ordered close-packed array was exploited to obtain a two-dimensional grating with hexagonal symmetry. Optical coupling into slab waveguides of both visible (633nm) and tunable infrared (1550 nm) lasers was characterized as a function of incident angle in a custom-made automated apparatus. Sensitivity to different aqueous solutions was demonstrated with low loss waveguides fabricated using low-frequency plasma-enhanced chemical vapor deposition. The exploitation of the tunability of telecom infrared lasers and of the two-dimensional hexagonal grating coupler has the ultimate goal of providing a high performance, compact sensor that does not require mechanical moving parts.

In this paper, we propose a novel integrated polarization analyzer sensor (IPAS) made by ion exchange on a glass substrate. It is capable to determine the polarization state of a light beam: elliptical, circular or linear. Furthermore, in the first case, the sensor measures the ellipse's eccentricity and the angle between its major axis and the x-axis of the IPAS (parallel to the glass' top surface). Also, for linear polarization, the angle between polarization direction and the x-axis of the IPAS is measured. The IPAS consists in two Y-junctions that gives three different outputs. The first one is directly one of the two output waveguides of the first Y-junction. The two other outputs are the waveguides following the second Y-junction. Before the latter, a piezoelectric plate creates an artificial anisotropy when it is excited electrically. For each one of the three output signals, a polarizer is inserted between the waveguide's end and a photo-detector. It is demonstrated here that, with adequate signal processing, it is possible to obtain all the information on the polarization state of a light beam.

We previously demonstrated light guiding in fiber-on-glass (FOG) dielectric waveguides using fluoro-tellurite glasses. These waveguides were fabricated by mechanically pressing a fiber onto a polished planar glass substrate of lower refractive index above the glass transition temperatures. However, two handling constraints have been discovered in this approach. In practice, for novel inorganic compound glasses, the minimum dimension of fiber that can be handled is preferably around 30μm. The minimum refractive index difference between the fiber and the substrate that can be reliably achieved at present with these glasses is 0.01. Our simulation results showed that, taken together, these restrictions provide a practical barrier to achieving single-mode FOG operation at telecommunications wavelengths. Here we present simulation and experimental results for a new inorganic glass FOG waveguide that simultaneously meets these handling constraints and achieves mono-mode operation around 1.55 μm. In this new design, a homogeneous glass fiber is partially embedded lengthwise in a substrate of higher refractive index glass; the nonembedded part of the fiber is air clad. Simulation results presented for fluoro-tellurite FOG waveguides confirm the success of the new design in realizing single-mode propagation at 1.55 μm for a fiber diameter of 30 μm and a fibersubstrate refractive index difference of 0.01. The design is robust, with good dimensional fabrication tolerance, but predicted losses are over 6 dBcm^-1. A proof-of-principle demonstrator is fabricated using two commercially available multi-component silicate glasses (Schott F2 and F4). This shows multimode waveguiding at 0.633 μm, guidance around a curve, and appears mono-mode at 1.575 μm.

We report on the characterization of highly photorefractive Er³⁺/Yb³⁺-doped silica-germania planar waveguides deposited by radio-frequency-magnetron-sputtering technique. Details of the deposition process in order to get low loss, single mode waveguides at 1550 nm are described. The material presents an intense absorption band in the UV region and irradiation by a KrF excimer laser source produces large positive refractive index changes, without the need of particular sensitization procedures. Dark line spectroscopy of the waveguide modes at 635 nm was performed to calculate the index change under UV exposure. Highly efficient photo-induced phase gratings have been fabricated in the slab waveguide. Waveguides spectroscopic properties of the ⁴I_13/2 <=> ⁴I_15/2 transition of the Er³⁺ ion, including lifetime and emission bandwidth, were examined. Photoluminescence excitation spectroscopy was also recorded to detect the Yb³⁺ to Er³⁺ energy transfer process.

An improved synthesis of inorganic-organic hybrid silica-zirconia sol-gel material has been developed, and it has controllable refractive index and can form ten-micron-thick film in a single spin coating process. The novel synthesis was realized by uniform hydrolysis and subsequent copolymerization of [3-(methacryloxy) propyl] trimethoxysilane and zirconium propoxide. The optical properties of the prepared sol-gel material was studied and characterized by a series of experiments. Compared with the sol-gel films reported before, the sol-gel film had good internal homogeneity and surface uniformity due to single layer structure. We employed the hybrid silica-zirconia sol-gel film in the singlestep fabrication of a dielectric channel waveguide on a quartz substrate. In the fabrication process, the sol-gel film was exposed to UV through a binary mask, and the exposed zone within the film formed a channel waveguide core because of its refractive index increase. The channel waveguide core was then covered again with a layer of the same kind of sol-gel film, and the unexposed zone within the sol-gel film, along with the new cover layer, formed the cladding of final dielectric channel waveguide. The novel sol synthesis enabled a precise control of the geometrical and optical parameters of the channel waveguide. In the 1.55 μm telecommunication window, the fundamental modes TE₀₀ and TM₀₀ in the channel waveguide had acceptable transmission losses of 1.20 ± 0.06 dB / cm and 1.79 ± 0.06 dB / cm, respectively.

Polymer optical waveguide devices will play a key role in several rapidly developing areas such as optical networks, biophotonic and fluidic applications. We have developed a technology which enables the increase of the refractive index of methylmethacrylate based polymers by deep ultra violet (DUV) radiation. The modification of the dielectric properties of polymers by DUV is a useful technique for the realization of photonic integrated optical circuits. The technique presented here has several advantages with respect to common methods because only a single polymer layer is used, which serves as the substrate and waveguide as well and no further etching or development step is required. This method can not only be applied to planar polymer substrates but also to preembossed substrates. This enables the fabrication of ridge waveguide based devices by hot embossing. Nickel stampers with feature heights of about 15-20 μm and aspect ratios usually between 2:1 and 3:1 can be utilized for replication without major effort. Nickel stampers are not only used to replicate optical waveguides, but are also used to realize fluidic channels in the range of several microns. UV modification of methylmethacrylate polymers additionally leads to a new surface chemistry affecting the selective absorption of proteins and the adhesion of living cells in vitro. The bi-functionality of the modified polymer chips supporting waveguides and cell anchorage capabilities at the same time provides the opportunity to monitor protein adsorption, cell attachment and spreading processes by evanescent-field techniques.

Different electro-optic polymer systems are analyzed with respect to their electro-optic activity, glass transition temperature (T_g) and photodefinable properties. The polymers tested are polysulfone (PS) and SU8. The electro-optic chromophore, tricyanovinylidenediphenylaminobenzene (TCVDPA), which was reported to have a high photochemical stability ¹ has been employed in the current work. Tert-butyl-TCVDPA, having bulky side groups, was synthesized and a doubling of the electro-optic coefficient (r33) compared to the unmodified TCVDPA was shown. A microring resonator design was made based on the PS-TCVDPA system. SU8 (passive) and TCVDPA (active) channel waveguides were fabricated by the photodefinition technique and the passive waveguide losses were measured to be 5 dB/cm at 1550 nm.

The paper reviews key characteristics of ultra fast evanescently coupled waveguide-integrated p-i-n photodetectors for 1.55μm wavelength. In detail, a highly efficient 100 GHz photodetector module and a low-capacitance miniaturized photodiode with 120 GHz bandwidth employing an optical matching layer for enhanced responsivity are reported. Furthermore, recent results on monolithically integrated traveling wave photodetectors based on discrete miniaturized photodiodes with parallel optical feed are presented.

This paper reports the design, realisation, and characterisation of singlemode hollow conductive waveguides for stellar interferometry. These waveguides are developed in the frame of technological developments for the ESA DARWIN mission, which aims at direct detection of exoplanets and biomarkers on them (proof of life) using nulling interferometry in the 6-20 μm spectral range. The use of singlemode waveguides is mandatory in order to meet DARWIN required performance by achieving a modal filtering better than 10^-6. While there is ongoing developments of infrared dielectric fibers or integrated waveguides, both using chalcogenide glasses or silver halide compounds, this paper presents the first realisation and characterisation of singlemode hollow conductive waveguides in the DARWIN spectral range, by means of standard microelectronic and wafer bonding technologies.

In a dielectric waveguide, the optical power is confined mostly in the core of the waveguide, where the refractive index is highest. Outside of the core the field is evanescent, i.e., the field strength decreases exponentially with the distance from the core. This evanescent field can be used to manipulate microparticles. For a particle with index of refraction higher than that of the surrounding medium (water), the optical forces due to the evanescent field act to guide the particle along the waveguide. The use of waveguides to trap particles combines the possibilities of conventional optical tweezers with the techniques employed in integrated optics, and it has the added advantage of integration of several functions on a single chip. We have experimentally observed size-dependent trapping and propulsion at velocities up to 33μm/s of polystyrene spheres, of diameters between 3 and 12μm, and in propulsion of 0.25μm diameter gold spheres at velocities up to 500μm/s. A Y-junction with a multimode input waveguide has been used to sort particles. By moving the input fibre relative to the input waveguide, the light goes into one of the two output branches. We have shown that this principle can be used to sort polystyrene microbeads. Recently we have used counter-propagating waves to move particles in both directions and also to stop a particle at a precise location. Experimental results and simulations for polystyrene microbeads, yeast cells and gold particles are presented.

We present experimental results of second harmonic generation enhancement through the resonance of the band edge in a photonic crystal based on lithium niobate. Proton exchange technique was used to fabricate a waveguide near the surface of the lithium niobate substrate. The photonic crystal structure over the waveguide was made by UV laser interferometry. Subsequently experiments were designed to quantify the Cerenkov second-harmonic generation (CSHG) radiated into the substrate. The SHG radiated inside the waveguides was also experimentally investigated. In our experiments, the second guided mode of the waveguide was tuned to the band edge resonance to enhance the second harmonic generation. The highest conversion efficiency of CSHG using photonic band gap (PBG) was around 50 times compared to SHG emission from non-patterned lithium niobate. A numerical model was used to corroborate the experimental result. It was also found that the SHG signal in the waveguides is quenched compared to the CSHG signal.

Recent progress in the development of planar reflective gratings has resulted in the demonstration of multiplexers, comb filters, interleavers, power monitors, and receivers for long-haul and metro-area networks. Until recently, all of these devices were based on a single-grating architecture. We have now successfully designed, fabricated, and tested optical chips that are composed of cascaded planar reflective gratings. The chips have been realized in both additive and subtractive dispersion configurations. The versatility of cascaded gratings was utilized to produce a variety of optical responses, including single-mode transmission of wide bands (> 100 nm) with simultaneous demultiplexing of narrow optical channels with Gaussian and box-like responses. We have further demonstrated that cascaded gratings can be used to suppress optical noise and improve isolation. The devices were fabricated using a standard silica-on-silicon process with a refractive index contrast of 0.82% and have a remarkably small footprint of less than 0.3 sq. cm. We discuss the potential for tailoring of cascaded planar reflective gratings for applications in biophotonics, spectroscopy, and telecommunications.

We report optical devices based on monolithic integration of multiple nano-structured optical functional layers. Ultraviolet (UV)-nanoimprint lithography along with thin-film deposition, high aspect-ratio reactive ion etching (RIE) and trench-filling technologies were used in fabrication and integration of individual nano-structured optical functional layers. Structures with sub-50 nm linewidth were required in order to achieve good optical performance in the near-UV and visible wavelengths. The ability to integrate multiple nanostructure-based optical layers opens a path for novel integrated optical devices, as well as a new strategy for driving both miniaturization and cost.

One integrated pair of OCDMA encoder and decoder based on holographic Bragg reflector technology was designed and fabricated to simultaneously provide two multiple wavelength-hopping time-spreading optical codes. We have successfully demonstrated an encoding/decoding operation of two codes in 1.25-Gbps OCDMA testbed. A double-pass scheme was employed, enabling the implementation of much longer code length.

With the ever increasing bandwidth of optical communications systems, it is critical to allow multiple users to access the available bandwidth. Code division multiplexed access (CDMA) is especially attractive in local area networks due to the large number of subscribers possible, the security and the simple architecture. Here we presents novel encoding/decoding structures using anti-symmetric gratings with application in optical CDMA and optical encryption.

Circular resonators are fundamentally interesting elements that are essential for research involving highly confined fields and strong photon-atom interactions such as cavity QED, as well as for practical applications in optical communication systems as and biochemical sensing. The important characteristics of a ring resonator are the Q-factor, the free spectral range (FSR) and the modal volume, where the last two are primarily determined by the resonator dimensions. The Total-Internal-Reflection (TIR) mechanism employed in "conventional" resonators couples between these characteristics and limits the ability to realize compact devices with large FSR, small modal volume and high Q. Recently, we proposed and analyzed a new class of a resonator in an annular geometry that is based on a single defect surrounded by radial Bragg reflectors on both sides. The radial Bragg confinement breaks the link between the characteristics of the mode and paves a new way for the realization of compact and low loss resonators. Such properties as well as the unique mode profile of the ABRs make this class of devices an excellent tool for ultra-sensitive biochemical detection as well as for studies in nonlinear optics and cavity QED.

Broadband wavelength (de)multiplexers play a key role in different fields of integrated optics. In particular, the development of Erbium Doped Waveguide Amplifiers (EDWA) requires efficient integrated pump/signal multiplexers. In this article, the design and the realization of a 980 nm/1550 nm wavelength multiplexer based on a segmented asymmetric Y junction made by silver/sodium ion exchange on glass is discussed. We first present the behavior of an asymmetric Y junction, in order to describe its use as a wavelength (de)multiplexer. Then, the index averaging principle of a segmented waveguide is detailed, as well as its application in the design of one of the asymmetric Y junction branches. The design of a segmented asymmetric Y junction is then described, as well as its BPM simulations results. They show isolation of 33 dB at 980 nm and 25.6 dB at 1550 nm with excess losses of 2.6 dB at 980 nm and 1.3 dB at 1550 nm. In a second time, we present the realization of this component using a Silver/Sodium ion-exchange on glass. For λ = 980 nm, the isolation measured is (31 ± 1) dB, and in the third communication window, the isolation increases from (11.5±0.25) dB at λ = 1500 nm to (15.5±0.25) dB at λ = 1600 nm. The broadband operation is only limited by the modal characteristics of the waveguides composing the junction and ranges from 1500 nm to 1650 nm. Total insertion losses measured at 980nm are (2.63±0.1) dB. Around 1550 nm, losses vary from (3.6 ± 0.1) dB at the 1500 nm wavelength to (4.6 ± 0.1) dB at 1600 nm.

The fabrication of telecom active devices, such as waveguide amplifiers and lasers, with femtosecond laser pulses is of great industrial interest due to the simplicity, low cost and 3D capabilities of this technology with respect to the standard ones. In this work we will present the various improvements that brought us to demonstrate net gain and the first waveguide laser fabricated with femtosecond laser pulses on an erbium-ytterbium-doped phosphate glass. The first results have been obtained with an amplified, low repetition rate (1 kHz), Ti:Sapphire system. The target of matching the mode field of the fabricated waveguides to that of standard telecom fibers pushed us to develop a novel astigmatic focusing of the writing beam to overcome the asymmetry of the waveguide transverse profile intrinsic in the transversal writing geometry. Despite the circularization of the transverse profile, the high coupling losses allowed only for internal gain in an all-fiber coupling configuration. The best results have been obtained with a very compact, unamplified, diode-pumped Yb:glass laser, with a higher repetition rate (166/505 kHz) and lower energy. In this case, the waveguides exhibited almost perfect mode matching with a telecom fiber allowing coupling losses as low as 0.18 dB and propagation losses of 0.5 dB/cm. Such figures enabled net gain when pumping with 980-nm laser diodes and laser action by terminating the waveguide with two fiber Bragg gratings. These results pave the way to a transfer of femtosecond waveguide writing into the industrial arena for the realization of practical telecom components.

Capillary Electrophoresis Doping (CED) technique is proposed for the new doping technique of the functional molecules into the hybrid materials. Organic-inorganic hybrid films or waveguides are fabricated on the cathode and the capillary tube bridge is made between the hybrid materials and the anode solution bath. The capillary and the anode bath are filled with the solution of the functional molecules and DC voltage is applied between cathode electrode and the anode one. The functional molecules (ions) move along the electric field, and their doping into the hybrid materials can be attained by the control of the capillary position and the electric current through the circuit. In this study, siloxane based hybrid films and waveguides are prepared, and the doping of organic laser dyes, Rhodamine6G and Cresyl violet are demonstrated using SiO₂ glass capillaries. It is shown that CED technique has a great potential to fabricate the multifunctional optical devices in which various different functional chemicals are contained.

We describe a method to achieve phased array steering at the near infrared (i.e., optical) frequencies used in telecommunication (1550 nm) as an alternative to physical movement of standard mirrors. A stationary and planar multi-layer device utilizes a chalcogenide phase change material^1,2 (PCM) as its active element whose refractive index changes by very large amounts (> 1.7X) between its amorphous and crystalline states. The optical phase angle upon reflection off this surface can change by more than 180° depending on physical state of the PCM. Phasor analysis is used to explain how such large phase angle shifts can be accomplished for a PCM layer only 20 nm thick. Not only can this be used to make rewritable diffractive elements, but since the phase taper can be made nearly continuous, the surface can also steer the beam in non-specular directions with no diffractive distortions. To date, we have steered a telecom beam 2° in one direction, and expect deflections by more than 10°. The steering is broad-banded, self latching, and potential switching speeds are expected to be less than 100 ns.

We have investigated the dispersion properties of photonic crystal waveguide resonators. A passive InGaAsP/InP slab waveguide structure was used for the fabrication of the samples. The PhC waveguide resonators were defined by the omission of several rows of holes along the ΓΚ or ΓΜ direction of a triangular photonic crystal lattice. In addition, mirrors with a thickness of 1 to 4 rows of holes were inserted into the waveguide. An optimized dry etch process was used to etch the patterns to a depth of 3.5 µm through the waveguide layer. The group delay of the PhC devices was measured using the phase shift technique. The signal of a tunable laser was modulated at 3 GHz using a LiNbO₃ Mach-Zehnder modulator and detected with a high-frequency lightwave receiver. A phase sensitive detection with a network analyer measured the phase shift of the transmitted signal, which is proportional to the group delay. Close to the center of the resonances, the chromatic dispersion reaches values of -250 ps/nm and 250 ps/nm. This corresponds to the chromatic dispersion of 15 km standard fiber.

In this paper, we present the design, fabrication, and characterization of large-diameter semiconductor ring lasers with a single out coupling waveguide using AlGaAs/GaAs multiquantum well wafer. We also investigate the influence of the coupling between the ring cavity and the straight waveguide on the threshold current. It was found that the threshold current reduces with the decrease of the coupling between the ring cavity and the waveguide due to the widening of the coupling gap. By optimizing the coupling gap, we achieve a device with the threshold current of as low as 49mA.

Thanks to the maturing of rare-earth highly-doped materials, erbium-doped waveguide amplifiers (EDWAs) present a compact alternative to fiber amplifiers. While ion-exchanged EDWAs implemented on glass substrates provide the best passive characteristics, EDWAs based on thin films technologies offer a higher integration and amplification efficiencies. This paper proposes the realization of EDWAs in a new configuration which combines all these advantages. Indeed, this optical amplifier consists of an erbium/ytterbium-codoped glass guiding layer reported on an ion-exchanged strip formed on a passive glass substrate. The electromagnetic principle of operation of this hybrid structure is presented as well as simulations of its behaviour. Then, the realization and characterization of two different hybrid amplifiers is presented: the first one, based on a Tl⁺/K⁺ ion-exchanged strip provides a high gain coefficient of 3.66 ± 0.25 dB/cm; whereas the second one, realized with a Ag⁺/Na⁺ ion-exchanged strip, presents a good coupling efficiency with optical fibers, which allows the measurement of a 1 dB net gain.

We theoretically investigate the superprism effect in a polymer "woodpile" photonic crystal structure. We find that the common degeneracy problem caused by low index contrast can be avoided at certain frequency range. As a result, polymer materials such like photoresist manifest their potential for high performance superprism. We study the superprism effect for 3^rd and 4^th bands at frequency 0.94c/a using plane wave expansion method. In both cases, the wave propagation direction changes rapidly responding to variation of incident angle. Up to 30 degree of output angle variation for 1 degree of incident angle increment has been observed. We also find an average of 10 degrees shift of output angle for 1% variation of the incident wavelength. We fabricated the proposed "woodpile" structure based on multilayer 3D photolithography. This method, which uses commercially available photoresist, allows batch fabrication of 3D photonic crystals (PhCs), possesses the flexibility to create a variety of different lattice arrangements and the scalability for different operation wavelengths. We describe in this paper how to achieve 3D confined exposure and multiple resist application. We show the fabricated devices for both mid-infrared and telecom applications.

Integratable lasers were studied by using plastic waveguide laser made of laser dye doped PMMA. The wavelength coverage was over 400 nm∼1100nm and the laser waveguides showed durability of more than millions. Optically pumping system with waveguiding technique was also proposed, and laser integration techniques were studied for micro-spectroscopic application.

Wafer bonding became in the last decade a very powerful technology for MEMS/MOEMS manufacturing. Being able to offer a solution to overcome some problems of the standard processes used for materials integration (e.g. epitaxy, thin films deposition), wafer bonding is nowadays considered an important item in the MEMS engineer toolbox. Different principles governing the wafer bonding processes will be reviewed in this paper. Various types of applications will be presented as examples.

We report on the demonstration of several integrated slab-waveguide-based concentric Fabry- Perot resonators employing holographic Bragg reflectors as curved 2D cavity mirrors. The cavities, fabricated in a low-loss silica-on-silicon slab waveguide using high-fidelity deep ultra violet photolithographic fabrication, exhibit Q-factors approaching up to 10⁶ which are competitive with silicabased ring resonators. The Q-values achieved indicate very high slab waveguide homogeneity providing wavefront stability and extremely low loss from the volume-holographic lithographically scribed mirrors. Compared to silica-based ring resonators, the folded Fabry-Perot resonator design allows access to a substantially larger free spectral range by cavity shortening. Pathways to the implementation of highreflectivity and low loss distributed reflectors promise new directions in photonic integration with applications in sensing, filtering, and signal transport.

The wafer bonding of III-V semiconductor materials with garnet thin films has become of increasing technological importance in integration of optical components. The wafer bonding between InP wafer and GGG was demonstrated by using O₂ plasma surface activation. The same process was applied to the bonding process of InP/Ce:YIG, which is indispensable for the fabrication of an integrated optical waveguide isolator.

Traditionally, glass has been a suitable waveguide material and passive integrated optical circuits in glass substrates are widely used as passive components. Long-term tests of optical glass flats with a high level of internal stress revealed gradual systematic-change with time to produce inconsistent results. Since long-term stability has been the primary concern for users of specific applications, investigations of instabilities in various optical materials have been carried out via measurements and tests. From the development of the integrated optical systems' point-of-view, polymers are promising candidates that possess excellent compatibility with all other materials and their associated processes. Polymeric materials offer large refractive-index contrasts, high performance, environmental stability, simple low-cost fabrication and may be processed by unconventional forming techniques. Polymer technologies can be designed to form stress-free films, so that stress-induced losses can be eliminated. Optical polymers may also be tailored to meet specific requirements for optical waveguide devices and can be highly transparent in such a way that they are not a limiting factor in components' lifetime. In this paper, tests results and characteristics of polymeric materials shall be reviewed; different types of polymer are detail-studied and a brief analysis shall be presented. Examples of passive polymeric integrated optical components are single-mode splitters, couplers, polarizers, routers, gratings, bend waveguides, power dividers, wavelength filters and wavelength multiplexers/de-multiplexers, which may find applications in the optical communication and the telecommunication industries.

The purpose of this work was to develop a design methodology for the fabrication of proton exchanged channel waveguides in LiNbO₃ operating in the singlemode regime at several wavelengths, with specifice characteristics required to optimize integrated devices. To achieve this, it is necessary to obtain the relations between the optical characteristics of the waveguides and their repective fabrication conditions, and to introduce models of the waveguide formation process. The relations between fabrication conditions and optical characteristics of planar waveguides realized by proton exchange in benzoic acid are documented extensively in the literature. However, reports on the characterization of waveguide fabrication processes, performed in a systematic way, could not be found, resulting in the need to combine information from several sources. Discrepancies among results from different researches are evident, resulting from different experimental methodologies and calibration of equipment. Therefore, aiming at extracting a consistent data set, optical characterization techniques of the refractive index profile were employed to study series of samples.

This paper addresses the design, fabrication and packaging issues of SSOP(super slim optical pickup) module using blury technology. By using blu-ray technology, which uses a 407nm LD (Laser Diode) and an objective lens having NA (Numerical Aperture) 0.85, storage devices become miniaturized but have a high capacity. The developed prototype uses the integrated structure of a SiOB (Silicon Optical Bench) and a mirror substrate. The SiOB should be processed in order that a thin film PD(Photodiode) and interconnections, LD, Lens, QWP(Quarter Wave Plate) and HOE can be placed, and on the Silicon Substrate should Micromachined Silicon Mirror be formed. The SiOB is aligned and bonded with the wafer on which Silicon Mirror was formed. Then, it is diced. Because it is fabricated through this order, the super slim optical pickup can be fabricated by using wafer-level process. As a final step LD on the SiOB and HOE are mounted, assembled and bonded using an active alignment. The proposed SSOP was prototyped and characterized by measuring wavefront error and detecting static focusing and tracking error signals.

In this paper, we have developed the design method for planar holographic Bragg reflectors by layer-peeling algorithm. Layer-peeling algorithm is known as an efficient tool for synthesizing fiber Bragg grating which is one-dimension gating. We have modified the layer-peeling algorithm that can synthesize planar holographic Bragg reflectors. In order to solve the difficulty of fabricating the negative parts of apodization in planar holographic Bragg reflectors, we use iterative layer-peeling algorithm with fabrication constraints. The designed planar holographic Bragg reflector with 1 lob is 5.7 mm long, containing no phase shift. The stopband isolation is −30 dB. The bandwidth utilization factor is 68%. The dispersion is 91 ps/nm in the 0.54 nm passband at −1 dB. The group delay ripple is below 0.6 ps. The novel designs for the passband WDM filter that we have demonstrated is easier to manufacture.

Waveguides fabricated in high-index-contrast material systems offer very strong light confinement compared to that achieved in low-index-contrast material systems. A core layer of silicon (refractive index n~3.5) surrounded by silica cladding (n~1.5) on a silicon-on-insulator (SOI) substrate is an example of a high-index-contrast material system. This enables miniaturization of functional optical components and enhances dense integration of devices on waveguide chips. Some physical effects, such as, Raman and Stimulated Brillouin Scattering (SBS) are much stronger in silicon than in glass. In view of the above two reasons, it is possible to use short (a few centimeter long) silicon waveguides to amplify light or modify its wavelength, instead of using kilometers of glass optical fibers. A large mismatch between the common optical fiber dimensions and that of the high-index-contrast waveguides makes it difficult to couple light in and out of the chip. A number of techniques have been utilized for this purpose, including prism couplers, grating couplers, tapered fibers and micro-lens mode transformers [ 1, 2]. A better option to effectively couple light in this situation is by incorporating a waveguide section that is tapered vertically, as well as laterally between the fiber and the waveguide. This tapered section acts as a classic adiabatic modal transformer [ 3, 4, 5, 6] that transforms the input fundamental mode shape to that of the waveguide mode. In this paper, coupling losses between optical fibers and rib-loaded SOI waveguides with lateral only (1-D) and combination of lateral and vertical (2-D) tapers are presented. The waveguide fabrication process down to 0.75 μm size with the tapers is discussed and the measured coupling losses are compared to predictions. Measured coupling loss values for waveguides with 2-D tapers (~1.8 dB) show a significant improvement over those for waveguides with 1-D tapers (~4 dB) or no tapers (~8 dB), and are in excellent agreement with predictions. A qualitative analysis of the Free Carrier Absorption (FCA) phenomenon in narrow silicon waveguides that suppresses the Raman amplification and SBS is also shown.