Practical use of sum-frequency generation in multilayer waveguides is investigated for the purpose of frequency stabilisation in multichannel optical networks. Experimental results are presented on both wide and narro...
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Practical use of sum-frequency generation in multilayer waveguides is investigated for the purpose of frequency stabilisation in multichannel optical networks. Experimental results are presented on both wide and narrow-range wavelength sensing in the 1.3 mum communication band using simple optoelectronic components. optical frequency difference measurement resolution is estimated to be better than 2 GHz.
We report on a study of optical gain in chromium-doped LiNbO3 waveguides formed by the proton-exchange process. optical gain in proton-exchanged Cr: LiNbO3 channel waveguides has been measured for the first time. Thes...
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We report on a study of optical gain in chromium-doped LiNbO3 waveguides formed by the proton-exchange process. optical gain in proton-exchanged Cr: LiNbO3 channel waveguides has been measured for the first time. These wave-guides show potential for diode-laser pumping of an integrated, broadband tunable laser in the 750-1150 nm spectral range.
The realisation of a thermo-optical Mach-Zehnder interferometer switch based on SOI (silicon-on insulator) material is reported. At a wavelength of 1.3mum, on-off ratios of 13dB (TE) and 9dB (TM) are achieved with a s...
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The realisation of a thermo-optical Mach-Zehnder interferometer switch based on SOI (silicon-on insulator) material is reported. At a wavelength of 1.3mum, on-off ratios of 13dB (TE) and 9dB (TM) are achieved with a switching power of 150mW. The rise time is 5mus.
A compact configuration of three-dimensional optical interconnects using stacked ARROW-B waveguides is developed. A short coupling length of 200mum and a large tolerance to core thickness are demonstrated.
A compact configuration of three-dimensional optical interconnects using stacked ARROW-B waveguides is developed. A short coupling length of 200mum and a large tolerance to core thickness are demonstrated.
The tetrahedral tip is introduced as a new type of a probe for scanning near-field optical microscopy (SNOM). Probe fabrication, its integration into a scheme of an inverted photon scanning tunnelling microscope and i...
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The tetrahedral tip is introduced as a new type of a probe for scanning near-field optical microscopy (SNOM). Probe fabrication, its integration into a scheme of an inverted photon scanning tunnelling microscope and imaging at 30 nm resolution are shown. A purely optical signal is used for feedback control of the distance of the scanning tip to the sample, thus avoiding a convolution of the SNOM image with other simultaneous imaging modes such as force microscopy. The advantages of this probe seem to be a very high efficiency and its potential for SNOM at high lateral resolution below 30 nm.
A computer-aided design system for integrated devices is described, combining guided-wave circuit layout design and beam-propagation simulation of waveguide optics. The layout design includes efficient ways of generat...
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A computer-aided design system for integrated devices is described, combining guided-wave circuit layout design and beam-propagation simulation of waveguide optics. The layout design includes efficient ways of generating various waveguide routing geometries, interfaced with generation of data on the lithographic mask geometry and with a simulator of optical propagation through waveguide devices. The optical simulator includes two alternative algorithms for the beam-propagation method algorithms. Additional modules connected with specific waveguide fabrication technologies are described. Calculation examples are included, applying the system to problems handled in published literature.
The application of a novel optical evanescent wave sensor, the Resonant Mirror (RM), to the direct study of biological recognition studies is described. In particular, measurement of antigen/antibody and enzyme/substr...
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The application of a novel optical evanescent wave sensor, the Resonant Mirror (RM), to the direct study of biological recognition studies is described. In particular, measurement of antigen/antibody and enzyme/substrate/inhibitor interactions in real-time without labelling is detailed. The RM, described in the preceding paper (Cush et al., 1992), detects changes in refractive index and/or thickness occuring within a few hundred nanometers of the sensor surface. Several methods for immobilisation of biomolecules at the sensor surface have been investigated using antibodies and radioactively labelled antigens as model systems. One of the immobilisation techniques involves deposition of carboxymethyl-dextran on the sensor device and subsequent covalent attachment of biomolecules to the gel via their amino groups. With an anti-theophylline antibody, this method resulted in at least 212 femtomoles of active antibody per mm2 of the surface, a surface density equivalent to at least 9 monolayers of antibody. Immunoassays performed on the RM with immobilised antibodies resulted in sensitivities in the nM range for the complementary antigens. The specificity and sensitivity of the system was further improved by the use of sandwich or multi-site immunoassays and, by the use of enhancer particles, such as colloidal gold particles. The broader applicability of the RM to studies on molecular interaction studies was demonstrated in an assay for the proteolytic enzyme trypsin and the specific inhibition of enzyme activity by alpha1-anti-trypsin.
A low switching voltage of less than 2V was achieved in a GaInAs/InP MQW intersectional waveguide optical switch operating at 1.55-mu-m. This switch was fabricated by only one-step epitaxial growth followed by a patte...
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A low switching voltage of less than 2V was achieved in a GaInAs/InP MQW intersectional waveguide optical switch operating at 1.55-mu-m. This switch was fabricated by only one-step epitaxial growth followed by a pattern etching process using electron beam lithography for electrical isolation and photolithography for waveguide formation.
The Letter proposes and demonstrates a nondestructive and simple method for optical-waveguide loss measurement in which the end-fire coupling efficiency is optimised so that an input beam spot size becomes exactly the...
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The Letter proposes and demonstrates a nondestructive and simple method for optical-waveguide loss measurement in which the end-fire coupling efficiency is optimised so that an input beam spot size becomes exactly the same as the mode size of a guided wave. An accuracy of better than 0.05 dB/cm has been achieved in Ti: LiNbO3 waveguides.
A new bend configuration with curved comer reflector in the form of a logarithmic spiral is proposed. It is shown that this structure has a small size and very low bend loss for a large bending angle and small refract...
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A new bend configuration with curved comer reflector in the form of a logarithmic spiral is proposed. It is shown that this structure has a small size and very low bend loss for a large bending angle and small refractive index difference at the reflector interface.
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