Fluorinated polyimide waveguides with low polarization-dependentloss and their applications to thermooptic switches

Fluorinated polyimide waveguides with low polarization dependent loss (PDL) and thermooptic (TO) switches made from them were demonstrated. The waveguides showed loss of less than 0.3 dB/cm at the wavelength of 1.3 μm and 0.6 dB/cm at 1.55 μm for both TE and TM polarizations. The PDL's were less than 0.1 dB/cm. Extinction ratios of Y-branching-type TO switches fabricated from these waveguides were larger than 20 dB when over 160 mW of electric power was applied at 1.3 μm, and over 150 mW at 1.55 μm. The switching speed was faster than 8 ms     

Low-loss singlemode amorphous silicon waveguides

Amorphous silicon waveguides were obtained by plasma-enhanced chemical vapour deposition and anisotropic plasma etching. Rectangular multimode waveguides as well as singlemode ridge waveguides were fabricated. Scattered light measurements at 1550 nm (1300 nm) wavelength showed a low propagation loss of /spl les/0.5 dB/cm (1.6 dB/cm) for multimode waveguides and 2.0 dB/cm (5.0 dB/cm) for highly-confined singlemode waveguides.     

0.1 dB/cm waveguide losses in single-mode SOI rib waveguides

Waveguide losses as low as 0.1 dB/cm at a wavelength of /spl lambda/=1.3 /spl mu/m have been achieved in SOI rib waveguides fabricated by wet chemical etching. The single-mode waveguides have a large cross section yielding field mismatch losses to a standard single-mode fiber of only 0.17 dB/facet (both polarizations). Polarization independent fiber-chip-fiber insertion losses of 0.9 dB (best 0.5 dB) at a chip length of 60 mm have been measured.     

Fabrication of single-mode polymeric optical waveguides bylaser-beam writing

A laser-beam writing system is developed for large-area optical waveguide fabrication. Single-mode embedded channel optical waveguides are successfully fabricated on both 4- and 8-in silicon substrates using deuterated fluoromethacrylate polymers by laser-beam writing in photoresist and dry etching. The propagation loss of the waveguides is as low as 0.1 dB/cm at 1.3 μm     

Fabrication of LiTaO3 optical waveguides by Ni diffusionbelow the Curie temperature

Using Ni diffusion into LiTaO₃ below the Curie temperature for the fabrication of optical waveguides was presented for the first lime. Ordinary and extraordinary polarization waveguide modes were obtained. The index distribution profiles of both modes were measured by a prism coupler. Loss in planar waveguides at 0.6328 μm is 0.7±0.1 dB/cm for the ordinary mode and 1.3±0.2 dB/cm for the extraordinary mode. Moreover, a Mach-Zehnder interferometer was fabricated by this method for electrooptic characterization. The measured half-wave voltage is 5.5 V and the extinction ratio is greater than 29 dB     

Optical directional coupler using deposited silica waveguides (DS guides)

A new optical directional coupler using embedded single-mode glass waveguides is presented. The glass waveguides, called deposited silica waveguides (DS guides), were fabricated by depositing doped glass on a silica substrate after forming grooves by reactive sputter etching. Waveguide transmission loss was measured to be 1.3 dB/cm, and fiber-to-waveguide coupling loss was 0.1 dB. Using a tunable monochromatic light source, 96 percent power transfer or 14 dB isolation was measured. The DS guide directional coupler is compatible with single-mode fiber and is expected to be a useful component for future wavelength division multiplexing transmission systems.     

Narrow, high-NA GaAs/GaAlAs optical waveguides with losses below 0.7±0.1 dB cm-1

Losses as low 0.65 dB cm-1 (3 ?m width) and 0.3 dB cm-1 (8 ?m width) have been measured (? = 1.15 ?m) in high-confinement (NA ? 0.45) GaAs/GaAlAs optical waveguides grown by MOCVD. The Fabry?Perot loss measurement technique used in deduced to be accurate to ±0.1 dB cm-1. These are the lowest losses reported for gudies of high electro-optic merit in III-V materials.     

Low-loss high-silica single-mode channel waveguides

Low-loss high-silica single-mode channel optical waveguides of 0.1 dB/cm have been fabricated on crystal silicon substrates with fibre coupling losses of less than 0.05 dB by flame hydrolysis deposition and reactive ion etching. Directional couplers have also been fabricated with excess loss of 0.5 dB by this waveguide fabrication technique.     

Fabrication of SiO2-TiO2 glass planar optical waveguides by flame hydrolysis deposition

Low-loss SiO2TiO2 planar waveguides of 0.1 dB/cm have been fabricated by flame hydrolysis deposition suitable for mass-production. A CO2 laser was used to make a stripe waveguide structure for loss measurements.     

Influence of water sorption on acrylic polymer waveguide loss

The influence of water sorption on acrylic polymer waveguides was studied by measuring the loss changes in the atmosphere at 13 to 98% RH. The absorption peak at 1.41 μm increased from 0.5 to 2 dB/cm due to water sorption. This peak resulted in a small loss change of 0.03 dB/cm at 1.3 μm, which was successfully measured using a 57 cm waveguide with a loss of around 0.1 dB/cm. Relationships between loss change and water sorption were also revealed by measuring the water content of the polymers     

Low-loss polymeric optical waveguides fabricated with deuteratedpolyfluoromethacrylate

Deuterated polyfluoromethacrylate which has high transparency, low birefringence and good processability was newly synthesized for use as optical waveguide materials, and both single-mode and multimode optical waveguides were fabricated using the polymer. The propagation loss and waveguide birefringence of the single-mode waveguides were as low as 0.10 dB/cm and -5.5×10^-6 at 1.31 μm, respectively. The propagation losses of the multimode waveguides were less than 0.02 dB/cm at both 0.68 and 0.83 μm, and 0.07 dB/cm at 1.31 μm     

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     

Novel integrated optical polarisers using surface plasma waves and ion milled grooves in lithium niobate

Two distinctly different integrated optical polarisers have been made with multilayer claddings and titanium indiffused lithium niobate waveguides, transmitting both TE and TM polarisations. The TE device used claddings on the crystal surface obtaining (20.9±0.3) dB/cm extinction ratio. The TM polariser used similar claddings on a vertical wall fabricated by ion-beam milling adjacent to the waveguide, obtaining (17±3) dB extinction ratio.     

Erbium-doped fluoride glass waveguides

When calling for compact green laser sources, the green upconversion emission of IR pumped erbium-doped fluoride glass waveguides opens up a technologically and economically superior alternative to complex and costly frequency doubling techniques. Therefore, fluoride glass planar waveguides were fabricated with thicknesses down to 29 μm and a scattering loss of 0.1?0.2 dB/cm.     

玻璃基多模波导光功分器的研制

利用Ag+-Na+电场辅助玻璃基离子交换技术制作了低损耗的掩埋多模波导,并在此基础上研制了多模波导光功分器.测试分析了多模波导和光功分器的损耗和偏心率特性.所研制的多模直波导传输损耗小于0.1dB/cm,所制作的1×2的多模波导光功分器附加损耗小于1.3 dB.     

Extremely low loss InP/GaInAsP rib waveguides

The authors have fabricated InP/GaInAsP rib waveguides with losses as low as 0.18 dB/cm for the TE polarisation and 0.26 dB/cm for the TM polarisation. The length of the waveguides was 28 mm. These losses are measured with the Fabry-Perot method and repeated for different lengths of the waveguide for determining the reflection coefficient.<>     

Integration of magnetooptical waveguides onto a III-V semiconductorsurface

Optical waveguides fabricated on a yttrium iron garnet (YIG) substrate are integrated onto a semiconductor surface by using ridge waveguides patterned onto a prefabricated recess in the YIG surface. The recess separates the waveguides from the semiconductor substrate with an air-gap. This structure makes it possible to avoid coupling light within the YIG waveguides into the semiconductor substrate which has a higher refractive index. The excess optical loss due to the coupling can be as low as ⩽0.1 dB/cm with a 1-μm-wide air-gap. The calculated coupling loss is confirmed by comparing the guided TE and TM modes     

Attenuation measurements on MOCVD-grown GaAs/GaAlAs optical waveguides

We report loss measurements on MOCVD-grown GaAs/GaAlAs optical waveguides, by sequential cleaving with allowance for Fabry-Perot resonator effects. Upper bound values are 1.4 dB/cm for strip-loaded and 2.5 dB/cm for fully etched ridge waveguides.     

Low-loss straight and curved ridge waveguides in LPE-grown GaInAsP

Loss measurements on ridge waveguides in LPE-grown GaInAsP at a wavelength of 1.3 mu m are presented. An attenuation of 4.5 dB/cm has been obtained for straight waveguides, and for curved waveguides an excess loss at low as 0.7 dB was found for a 20.8 degrees S-bend with a radius of 300 mu m ( approximately=1.5 dB/90 degrees ).<>     

Polymer channel waveguides with low loss at 1.3 mu m

Highly transparent polymers in the 0.6-1.3 mu m wavelength region have been synthesised from deuterated or halogenated methacrylate monomers. Low loss waveguides of less than 0.1 dB/cm at a wavelength of 1.3 mu m have been fabricated using the polymers.<>