Monomode Optical Waveguides Research Articles

Monomode Optical Waveguide Achieved by Lattice Damage in Yttria-Stabilized Zirconia Crystal Induced from Energetic Oxygen Irradiation

With valuable physicochemical properties, yttria-stabilized zirconia crystal has promising advantages in optical applications. In this paper, the waveguide effect is observed in yttria-stabilized zirconia crystal irradiated by energetic oxygen ions. The waveguide properties and the field intensity are analyzed using prism and end-face coupling method arrangements, and the results show that monomode is found in the near-surface region and the light beam can be well confined in the waveguide structure, which shows refractive index distribution of the barrier-wall and enhanced-well type. The lattice damage induced by irradiation is investigated by the Rutherford backscattering/channeling experiment and high-resolution X-ray diffraction techniques. The simulation results are in good agreement with the experimental data.

Monomode Optical Waveguides in Yb3+-Doped Silicate Glasses Produced by Low-Dose Carbon Ion Implantation

Monomode Optical Waveguides in Yb³⁺-Doped Silicate Glasses Produced by Low-Dose Carbon Ion Implantation

Monomode Optical Waveguides in Yb3+-Doped Silicate Glasses Produced by Low-Dose Carbon Ion Implantation

The planar waveguide has been fabricated in the Yb3+-doped silicate glass by 4.0 MeV C2+ ion implantation at a dose of 2×1014 ions/cm2. The guided modes are measured using a model 2010 prism coupler at 633 nm. The near-field profiles of the planar waveguide are obtained with an end-face coupling system. The refractive index profile of the waveguide is reconstructed by the intensity calculation method, which shows a typical “enhanced well + barrier” distribution. The SRIM'2006 code is carried out to simulate the energy loss during the implantation in order to obtain a better understanding of the waveguide formation. After post-implantation treatment at 260 °C for 1 h, the waveguide possesses a propagation loss of ∼1.42 dB/cm. The acceptable guiding properties suggest that further waveguide lasers may be realized on the C-implanted Yb3+-doped silicate glass waveguides.

Fabrication of an Electro-Optical Temperature Sensor Based on Silicon Oxynitride Films Deposited by PECVD

We present the fabrication and characterization of an electro-optical temperature sensor based on silicon oxynitride dielectric films deposited by Plasma Enhanced Chemical Vapor Deposition at low temperatures (~300oC). The temperature sensor is basically a Mach-Zehnder interferometer such that a temperature difference between its arms produces a phase difference between the electromagnetic waves traveling through each arm thus originating a variation in the output optical power. In order to analyze the feasibility of this sensor, a temperature difference is imposed by applying a heating element in one of the arms. The results show that it is possible to control the optical device output through the adequate control of the heating element. Furthermore, the influence of heat propagation, multimode noise and methods to obtain monomode optical waveguides and self-sustained Mach- Zehnder structures are discussed in this work.

Monomode optical waveguide excited at 1540 nm in LiNbO3 formed by MeV carbon ion implantation at low doses

The monomode enhanced-index LiNbO(3) waveguide excited at 1540 nm is reported. X-cut LiNbO(3) crystals were implanted at room temperature by 6.0 MeV C(3+) ions with a dose of 2.0x10(15) ions/cm(2). Low loss planar optical waveguides were obtained and characterized by the prism coupling technique. Four dark modes were observed for extraordinary light at 633 nm, while only one enhanced-index mode was observed at 1540 nm. The propagation loss of the waveguide is 1.01 dB/cm measured with the moving fiber method. Reflectivity calculation method (RCM) was applied to simulate the refractive index profiles in waveguide. The width of waveguide structure induced by carbon ion implantation is ~3.6 microm.

Monomode optical waveguide in lithium niobate formed by MeV Si+ ion implantation

The monomode enhanced-index LiNbO3 waveguide fabricated by low-dose ion implantation is reported. LiNbO3 crystals were implanted with 3 MeV Si+ ions to doses around 1014 ions/cm2. After annealing, the waveguides were formed by the extraordinary refractive index enhancement in the waveguide regions. The effective extraordinary refractive index of the waveguide increased with ion implantation dose. The loss was 0.64 dB/cm in the X-cut sample with an implantation dose of 3.3×1014 ions/cm2. The scattering loss in the Z-cut samples was even lower than that in the X-cut samples.

Fabrication of Erbium-Doped Channel Waveguides by a Combination of Ion Exchange and Sol-Gel Techniques

Erbium-doped germano-silicate thin films of good optical quality were produced by the sol-gel technique. High refractive index changes of up to 0.018 were obtained by sodium-silver ion exchange. Monomode optical waveguides with Gaussian mode profile were fabricated by this technique. It is shown that, if the ion exchange process parameters are well chosen, the influence of the waveguide fabrication on the active properties of the material is negligible.

Automatic adjustment of monomode optical waveguides by a microsystem

An integrated microsystem is being developed which is able to handle the tight mechanical tolerances of monomode waveguide couplings by a controlled adjustment movement. It basically contains a two-axis microactuator for moving a fibre or a microlens, an optical sensor for the position detection, and a control circuit. Two types of microactuators, made completely by silicon micromachining, are investigated. The piezoelectric version contains a compliant mechanism with a two-stage hinge gear in order to enlarge the movement range. The electromagnetic system consists of several planar coils enabling bi-directional actuation. Both actuators easily cover an x - y displacement range of . As for position sensing, the most promising results are reached by detecting cladding modes resulting in a sharp signal minimum at the optimum position. The control algorithm is carried out by a microprocessor.

Fabrication of low‐loss 45° integrated mirrors on dielectric optical waveguides

AbstractHigh‐density low‐loss dielectric optical interconnection is demonstrated on a monomode optical waveguide compatible with microelectronics technology. Low‐loss self‐aligned integrated mirrors (SAIM) on a dielectric (polyimide‐silicon nitride‐polyimide) optical waveguide have been fabricated. Optimization of the reactive ion etching process has been made in order to obtain vertical, homogeneous etched sidewalls. Using such a process, 45° integrated mirrors present reflection losses of 0.6 dB at a 830‐nm wavelength (quasi‐TE mode).

Plasma-enhanced chemically vapour deposited Si 3N 4 thin films for optical waveguides

Silicon nitride films for applications in optical waveguides have been deposited by plasma-enhanced chemical vapour deposition (PECVD). Index of refraction, deposition rate, buffered HF etch rate and hydrogen content have been measured for different NH 3-to-SiH 4 ratios of precursor gases in the range 0.6–10. Results show that these magnitudes are nearly constant for 2⩽ NH 3: SiH 4⩽4. Thermal annealing of films deposited at high NH 3:SiH 4 ratios yields a large reduction (up to 70%) in the NH bond concentration as well as a densification of the films. Finally, geometrical parameters necessary for the design of rib-type monomode optical waveguides based on the PECVD silicon nitride films were calculated.

Model experiments with integrated optical input grating couplers as direct immunosensors

Using an input grating coupler instrument and monomode optical waveguides, we studied the adsorption of various proteins (e.g. human immunoglobulins G and A (h-IgG and h-IgA), and avidin) on the waveguide surface. In model experiments for immunoassays, we also monitored as a function of time the formation of the immuno-complex Ag-Ab between antigen (Ag) molecules adsorbed on the waveguide surface and antibody (Ab) molecules, for example, of adsorbed h-IgG vs anti-h-IgG, anti-goat-IgG (cross-reaction) and anti-h-IgA (negative test). We also studied the affinity reaction between adsorbed protein A and h-IgG. From the measured changes in the effective refractive indices N(TE 0) and N(TM 0) of the TE 0 and TM 0 modes, we determined the thickness d F′, the refractive index n F′, and the surface coverage Γ of the adsorbed protein adlayers and of the immuno-complexes.

Proton-exchanged optical waveguides in Y -cut lithium niobate

The fabrication of proton exchanged monomode optical waveguides on Y-cut lithium niobate is reported. Molten benzoic acid is used, but damage of the crystal surface is avoided.

Simple field calculation for monomode optical waveguides

By combining the idea of equivalent-step-index profiles (ESI) with well known approximations by Stewart and by Rudolph-Neumann, and using simplified expressions for Bessel and Hankel functions, field calculations for monomode optical waveguides become simple enough to be carried out on any small desk-top computer. A Basic program is supplied.

Near field radiation pattern of tapered monomode optical waveguides

The Near Field radiation pattern of a tapered monomode planar waveguide is investigated for the first time. A theoretical technique is developed and the results obtained are shown to agree sufficiently well with experiments performed on tapered ion-exchanged glass guides to permit using this technique to predict taper performance.

Attenuation in corrugated circular waveguides. Part 2: Experiment

Measurements of the attenuation characteristics of corrugated circular waveguides in the frequency range 8–11 GHz are described which support the theory given in Pt. 1 of the paper (see p. 1173). Both cavity techniques and waveguide measurements are deployed, and these lead to attenuation values which are about 40% above the predicted value for an ideal corrugated waveguide. However, it is believed that the discrepancy may be explained by the surface roughness of the metal and other imperfections. The actual measured value of the attenuation of the HE11 mode is just below the theoretical value for the TE010 mode in a comparable smooth-wall waveguide, emphasising the low values being measured. A new method is described for suppressing modes, which is based on the principle of the monomode optical waveguide.

Dielectric waveguides for millimetre-wavelength transmission

The letter describes the salient features of a parametric study of dielectric waveguides intended for millimetre-wavelength microwave transmission. The waveguide is an analogue of the monomode optical waveguide, and, if core and cladding are made from foam materials, with loss tangents of order 10−5, the HE11 mode attenuation is about 40 dB/km, and the group delay change is 0.35 ns/km over 1 GHz bandwidth centred at 40 GHz.

Propagation behaviour of cylindrical-dielectric-rod waveguides

The exact propagation behaviour is considered of cylindrical dielectric waveguides possessing a central core of higher permittivity than the surrounding cladding. Results are compared with those obtained by making the coremode and cladding-mode approximations. The former approximation is found to be valid for most purposes; the latter is much more restricted. Although the waveguide parameters chosen are representative of monomode optical waveguides, the results should find wider application.