Single-mode, phosphorus-doped silica waveguides in siliconV-grooves

Single-mode, phosphorus-doped glass waveguides have been formed in silicon V-grooves by chemical vapor deposition. The fabrication process is reproducible, involves few steps, and produces waveguides with a loss on the order of 0.1 dB/cm at a wavelength of 0.633 μm. These waveguides are compatible with passive V-groove fiber alignment and out-of-plane coupling from integrated taps and end facets to surface-mounted optoelectronic devices     

Monolithic Integration of a Waveguide Optical Isolator With a Distributed Feedback Laser Diode in the 1.5- μm Wavelength Range

We present first monolithic integration of a waveguide optical isolator with a distributed feedback laser diode (DFB LD) in the 1.5-mum wavelength range. The integrated devices are composed of 0.25-mm-long index-coupled DFB LDs and 0.75-mm-long semiconductor active waveguide optical isolators. The semiconductor active waveguide optical isolators are based on the nonreciprocal loss in the semiconductor optical amplifier (SOA) waveguides with ferromagnetic metals (Fe). The fabrication process consists of two steps of metal-organic vapor phase epitaxy to grow the DFB LD/SOA layer structures, one dry-etching process for the waveguide stripe formation, and three steps of electron-beam evaporation for the electrodes and ferromagnetic metals deposition. They showed single-mode emission at 1543.8nm and 4-dB optical isolation under a magnetic field of 0.1 T.     

A comparative study of silver diffusion in a glass substrate foroptical waveguide applications

Multimode optical waveguides are fabricated in two steps by electrodiffusion of silver ions in a soda-lime glass from a metallic coating and are characterized by the methods of integrated optics. In the first step, the electromigration process and the fabrication parameters are controlled through electrical measurements, and an effective diffusion coefficient is calculated at 230°C from the Nernst-Einstein relation as well. In the second step, a new experimental method, allowing the calculation of silver and sodium self-diffusion coefficients, is presented. It is based on the diffusion equation from which it is shown that, for two given values of ion concentrations, the two diffusion coefficients are deduced. Both diffusion coefficients and optical properties of the waveguides are discussed and compared to the results of other works with which we find good agreement     

Fabrication and characterization of micromachined rectangularwaveguide components for use at millimeter-wave and terahertzfrequencies

The fabrication and characterization of micromachined reduced-height air-filled rectangular waveguide components suitable for integration is reported in this paper. The lithographic technique used permits structures with heights of up to 100 μm to be successfully constructed in a repeatable manner. Waveguide S-parameter measurements at frequencies between 75-110 GHz using a vector network analyzer demonstrate low loss propagation in the TE₁₀ mode reaching 0.2 dB per wavelength. Scanning electron microscope photographs of conventional and micromachined waveguides show that the fabrication technique can provide a superior surface finish than possible with commercially available components. In order to circumvent problems in efficiently coupling free-space propagating beams to the reduced-height G-band waveguides, as well as to characterize them using quasi-optical techniques, a novel integrated micromachined slotted horn antenna has been designed and fabricated, E-, H-, and D-plane far-field antenna pattern measurements at different frequencies using a quasi-optical setup show that the fabricated structures are optimized for 180-GHz operation with an E-plane half-power beamwidth of 32° elevated 35° above the substrate, a symmetrical H-plane pattern with a half-power beamwidth of 23° and a maximum D-plane cross-polar level of -33 dB. Far-field pattern simulations using HFSS show good agreement with experimental results     

Tapered polymer single-mode waveguides for mode transformation

This paper presents a tapered polymer waveguide structure for coupling light between optical waveguides with differing geometries. Optical fibers, lasers, and other photonic integrated circuit components can be coupled with tapered waveguides. The polymer waveguide performs a mode transformation between different mode shapes and sizes. For example, the mode transformation can be from an elliptical laser diode mode to that of a circular optical fiber mode. The input and output of a tapered waveguide structure are analyzed, for the case of laser to fiber coupling, in order to determine the effect of misalignments on the coupling efficiency. Adiabaticity in waveguide propagation is discussed. The fabrication of our polymer waveguides is also described     

Birefringence control and dispersion characteristics of silicon oxynitride optical waveguides

The design, fabrication and characterisation of birefringent silicon oxynitride planar optical waveguides are described for applications at the wavelength of 1.54 mu m. Form birefringence is attained by interposing a thin silicon nitride film in the waveguide stack, and can be controlled by adjusting the nitride layer thickness. Dispersion characteristics of the oxynitride waveguides have been measured and compared with theory.<>     

Realization of integrated Bragg reflectors in DANS-polymerwaveguides

The fabrication of integrated optical Bragg grating reflectors in organic waveguides, utilizing a DANS (4-dialkylamino-4'-nitrostilbene) side-chain-substituted polymer is described. The devices operate in the 1.5-μm telecommunication window and exhibit a linear narrowband filtering action with good throughput and coupling efficiency. The effect of a small slant in the channel direction is investigated experimentally. The structures have also been switched from a low to a high transmission state via a thermal refractive nonlinearity     

Fabrication and characterization of integrated optical waveguidesin sulfide chalcogenide glasses

This paper reports on the fabrication process of As-S-(Se)-based chalcogenide glass optical waveguides using three techniques: photolithography, laser beam writing, and ion implantation. The fabrication method of the bulk sulfide glasses and the processing of integrated devices are described and assessed in light of the propagation characteristics and optical losses in each case     

厚二氧化硅光波导薄膜的制备

随着光通信的飞速发展，Si基SiO2平面光波导集成器件的应用更加重要和广泛。在Si基上制备高质量的厚SiO2薄膜，是制作SiO2光波导及其集成器件的基础。本文介绍了Si基厚SiO2薄膜的几种制备方法。     

Microfabrication techniques for chemical/biosensors

Microfabrication processes for chemical and biochemical sensors are reviewed. Standard processing steps originating from semiconductor technology are detailed, and specific micromachining steps to fabricate three-dimensional mechanical structures are described. Fundamental chemical sensor principles are briefly abstracted and corresponding state-of-the-art examples of microfabricated chemical sensors and biosensors are given. The advantages and disadvantages of either fabricating devices in IC fabrication technology with additional microfabrication steps, or of using custom-designed nonstandard microfabrication process flows are debated. Finally, monolithic integrated chemical and biological microsensor systems are presented, which include transducer structures and operation circuitry on a single chip.     

Fabrication of optical inverted-rib waveguides using UV-imprinting

In this paper we introduce a fabrication process for polymer rib waveguides that uses UV-imprint lithography. In the structure of an inverted-rib waveguide, the lower cladding of the waveguide is patterned by UV-imprinting and the waveguiding layer is subsequently spin-coated. That makes the thickness of the formed slab layer on the rib waveguide controllable by tuning the spin-coating parameters. The fabrication process utilizes two steps of UV-imprinting. The first one is to form a rigid polymer mold from positive tone photoresist. The second one is to pattern the waveguide lower cladding with the formed polymer mold. Through the two steps of UV-imprinting, rib waveguides can be fabricated without an etching procedure. We demonstrated the proposed fabrication process by fabricating 2-μm-wide waveguides operating in single mode at 1310 nm. With TE-polarized light, the fabricated waveguides show an average transmission of 58.6% in a 30 mm long waveguide, corresponding to a loss of 2.3 dB.     

Milled-groove method for fiber-to-waveguide couplers

We report a simple milled-groove process integrated with a two-step ion-diffused waveguide fabrication for efficient coupling between single-mode fibers and integrated optical waveguides andY- branches. We demonstrate such a coupling technique using a) a multimode transition to single-mode waveguide coupler, and b) an integrated optical 3-dB branching waveguide coupler from a single-mode fiber to silver/sodium ion-enchanged waveguide components. The coupling loss was about 1-2 dB over a propagation length of 2 cm at an operating wavelength of 633 nm.     

Double heterojunction GaAlAs/GaAs I/sup 2/L integrated circuits

The fabrication and DC characterisation of GaAlAs/GaAs double heterojunction bipolar transistors (DHBTs) grown by molecular beam epitaxy are described. This baseline process has been developed for the implementation of heterojunction integrated injection logic (HI/sup 2/L) integrated circuits. Results concerning an I/sup 2/L ring oscillator and a divide-by-two circuit are given.<>     

Erbium-doped waveguide fabrication via reactive pulsed laser deposition of erbium-doped oxyfluoride-silicate glass

Using reactive pulsed laser deposition, a thin film of erbium-doped oxyfluoride-silicate glass is deposited onto a fused silica substrate. Rib waveguides are fabricated from this film using reactive ion etching. The fabrication and characterisation of these waveguides are summarised. As a result of various characterisation experiments described here, it is concluded that close to stoichiometric transfer of material from the bulk to the film has been achieved. It is concluded, however, that strong quenching mechanisms are present in the film, significantly affecting the magnitude of the /sup 4/I/sub 13/2//spl rarr//sup 4/I/sub 15/2/ transition fluorescence lifetime.     

Experimental analysis and modeling of buried waveguides fabricatedby quantum-well intermixing

The fabrication of buried waveguides in InP-based quantum-well (QW) material through the use of implantation. Enhanced QW band edge blue-shifting is reported. First, the lateral selectivity of implantation-induced QW intermixing is investigated using a specially designed implantation mask and photoluminescence. The refractive index change of the intermixed material is measured near the band edge. In combination, the lateral resolution and the index difference have allowed for the fabrication of narrow buried waveguides in an InP-based laser structure. Detailed modeling of the mode excitation and beam propagation of these devices is performed, and results are compared with experimental near-field profiles. We demonstrate that the waveguides are single-mode for both TE and TM polarizations at wavelengths near the band edge. The potential applications of this waveguide structure include post-growth fabrication of buried waveguide lasers and other integrated components     

VCSELs with monolithic coupling to internal horizontal waveguides using integrated diffraction gratings

A VCSEL structure with output coupling to an internal waveguide using integrated diffraction gratings has been demonstrated. The design and fabrication of the monolithically integrated structure, including epitaxial regrowth, is discussed and initial device characteristics are presented. While horizontal waveguides can be used to route optical signals between monolithically integrated components, a small amount of transmission is retained in the top DBR to enable on-wafer testing. This monolithic structure has the potential to enable VCSEL-based photonic integrated circuits on GaAs.     

Methods for passive fiber chip coupling of integrated opticaldevices

A useful technique for high precision passive coupling of single mode optical fibers to integrated optical devices is crucial for cost effective packaging especially in multiport devices like switches (N×N) and other WDM components. These devices were fabricated on two different material bases, silicon on insulator (SOI) and polymers. In both cases the waveguides are based on the oversized rib waveguide concept and utilize silicon as a substrate. Two possible fabrication processes for this passive fiber chip coupling IN or ON silicon are presented and compared. The first approach involves a technology similar to flip chip fabrication using a sub- and superstrate, that allows separate processing of v-grooves for fiber alignment and the integrated optical devices. The self aligned mounting of the chip is achieved by a v-shaped rib-groove combination created by wet chemical etching, where the rib is the exact negative of the groove so that the flip chip is put on precisely defined crystal planes rather than on sensitive edges, which would be the case when using rectangular alignment ribs. The second approach utilizes the same chip for waveguides and fiber alignment structures which makes it possible to define both in the same lithographic step and thereby eliminating any vertical displacement. Processing difficulties arise primarily from completely different processing requirements of fiber aligning v-grooves and integrated waveguides. The need to define patterns of the size of only several microns (μm) in the proximity to deep grooves makes the use of an electrophoretic photoresist necessary that is deposited via galvanic means on the extremely nonplanar surface. Both processes allow for fiber chip alignment precisions in the sub-μm range which was also experimentally verified with coupling losses as low as 0.7 dB per end-face. The fabrication processes along with experimental and theoretical results are presented     

Optimized silicon antiresonant reflecting optical waveguides forsensing applications

The development of an evanescent field sensor with an integrated Mach-Zehnder interferometric (MZI) configuration requires the fabrication of optical waveguides with two main characteristics: (1) monomode behavior and (2) high surface sensitivity for sensing biomolecular interactions in a direct way (without labels). In this paper, we present an experimental study for the optimization of the different parameters of the waveguides that will be the basis of a highly sensitive optical sensor. After optimization, an MZI sensor has been fabricated and some sensing applications are shown. The designed waveguides are based on antiresonant reflecting optical waveguide (ARROW) structures and are fabricated with standard silicon technology     

Millimeter-wave substrate integrated waveguides and filters in photoimageable thick-film technology

This paper presents the design and fabrication of substrate-integrated waveguides and filters for use at millimeter-wave frequencies. The components described are fabricated using photoimageable thick-film materials. Measurements on V- and W-band waveguide-to-microstrip transitions are presented. Losses resulting from the reduced-height nature of the waveguides are extracted from thru-relect-line calibration standards illustrating the effect of current losses in the broadwalls of the waveguides. The design of fourth-order 0.01-dB ripple Chebyshev resonant cavity filters operating at V-, W-, D-, and G-band is presented. The measured results of all components are in excellent agreement with simulated predictions.     

玻璃基集成光学器件研究进展

综述了玻璃基集成光学器件离子交换工艺的原理及技术现状,介绍了近年来我们在玻璃基光波导制作工艺方面的研究工作,并提出了研究工作面临的问题.