The outage probability in an under-addressed optical MIMO system may be reduced by configuring an intra-link optical mode mixer to dynamically change the spatial-mode mixing characteristics of the link on a time scale that is faster than the channel coherence time. Provided that the MIMO system employs an FEC code that has a sufficient error-correcting capacity for correcting the amount of errors corresponding to an average state of the MIMO channel, this relatively fast dynamic change tends to reduce the frequency of events during which the number of errors per FEC-encoded block of data exceeds the error-correcting capacity of the FEC code.

Intra-link spatial-mode mixing in an under-addressed optical mimo system

An optical waveguide circuit includes a first loss component for causing a diffraction loss of light propagating through an optical waveguide, and a second loss component provided at least one of before and after the first loss component, for causing a diffraction loss less than the diffraction loss in the first loss component to the light propagating through the optical waveguide. This enables the beam spot size of the lightwave launched into the first loss component to be magnified seemingly, and to reduce the radiation angle of the lightwave at the first loss component, thereby making it possible to reduce the excess loss involved in the propagation of the light through the optical waveguide.

Optical waveguide circuit

Compounds of formula (I) are useful as inhibitors of trypsin like serine protease enzymes such as thrombin, factor VIIa, factor Xa, TF/FVIIa, and trypsin. These compounds could be useful to treat and/or prevent clotting disorders, and as anticoagulating agents.

Biaryl compounds as serine protease inhibitors

[Problems] The present invention provides a photocurable resin composition having excellent adhesion with a substrate and excellent resolution; a film obtained by using the photocurable resin composition; a cured product obtained by curing the photocurable resin composition; and a printed wiring board comprising the cured product. [Means for Solution] The photocurable resin composition according to the present invention is characterized by comprising (A) a carboxyl group-containing resin, (B) an acylphosphine oxide-based photopolymerization initiator, (C) a titanocene-based photopolymerization initiator, (D) a photosensitive monomer and (E) a polymerization inhibitor.

Photocurable resin composition, dry film, cured product and printed wiring board

A passive temperature-compensated integrated optical component having an array of adjacent waveguides, and a slab waveguide located within a groove at an intermediate section of the array. The waveguides have an index of refraction that increases with increasing temperature, and the slab waveguide has an index of refraction that decreases with increasing temperature. The slab waveguide compensates for a temperature-induced change in the refractive index of the waveguides to maintain a generally constant optical path difference between the adjacent waveguides over a temperature range.

Phasar athermalization using a slab waveguide

An optical waveguide circuit includes a plurality of waveguides with different lengths. Grooves (12) are formed in the waveguide by removing the upper cladding and the core of the waveguide (4) or by removing the upper cladding, the core and the lower cladding of the waveguide (4), and filled with a material (10) which have a refractive index temperature coefficient whose sign is different from the temperature coefficient of the effective refractive index of the waveguide. The difference between the lengths of the removed parts of the adjacent waveguides is proportional to the difference between the lengths of the remaining parts of the adjacent waveguides.

Optical waveguide circuit, its manufacturing method and optical waveguide module having the optical waveguide circuit

A guided-wave circuit with a phase adjusting plate which adjusts optical path length errors, occurring during the manufacture of PLC, by an additional processing performed after the production of the PLC; and a method for producing the guided-wave circuit. A guided-wave circuit with an amplitude adjusting plate which adjusts the amplitude characteristics of light by an additional processing performed after the production of the PLC; and a method for producing the guided-wave circuit. A guided-wave circuit with a birefringence adjusting plate which adjusts the birefringence of light by an additional processing subsequent to the manufacture of the PLC; as well as a method for producing the guided-wave circuit. The guided-wave circuit includes a groove crossing a plurality of waveguides constituting the optical waveguides, a plate having optical characteristics spatially changed so as to adjust the optical characteristics at the intersections of the plate with the optical waveguides when the plate is inserted into the groove, and an adhesive for fixing the plate in the groove. The guided-wave circuit also includes both a phase adjusting plate and an amplitude adjusting plate to achieve further improvement in the optical characteristics. An apparatus for producing these optical characteristics adjusting plates is also included.

Guided-wave circuit with optical characteristics adjusting plate method for producing it, and apparatus for producing optical characteristics adjusting plate

We report dispersion resulting from phase and amplitude errors in arrayed-waveguide grating (AWG) multiplexers–demultiplexers. We measure the phase- and amplitude-error distributions of two different types of AWG and discuss their effects on the dispersion. The results show that the origin of the dispersion in the AWG is the low-order Fourier components of the symmetric phase and the antisymmetric amplitude errors. We also discuss the dependence of the dispersion on the passband shape in the presence of the same fabrication errors.

Dispersion resulting from phase and amplitude errors in arrayed-waveguide grating multiplexers-demultiplexers.

Optical waveguide circuit and optical waveguide module having the optical waveguide circuit

PURPOSE:To provide the optical circuit parts having wavelength selectivity capable of changing the Bragg wavelength of a diffraction grating disposed on an optical waveguide or the optical path length of another optical element after setting thereof by providing the optical circuit parts with the diffraction grating disposed on a optical waveguide and a metallic thin film heater disposed on the diffraction grating. CONSTITUTION:The optical circuit parts are composed of the metallic thin film heater 1 on the diffraction grating 2a, a core 3a of the optical waveguide, a silicon substrate 4a, an overclad 5a of the optical waveguide and an underclad 6a of the optical waveguide. Namely, the metallic thin film heater 1a is formed atop the overclad on the diffraction grating, by which the part of the diffraction grating 2a is changed to about 10 deg.C room temp. In actuality, the change of the Bragg wavelength when the metallic thin film heater 1a is driven is such that the Bragg wavelength increases as the driving electric power of the metallic thin film heater 1a is increased. Then, the Bragg wavelength is easily changed by adjusting the driving electric power of the metallic thin film heater 1a.

Hiroaki Yamada

Papers

Optical waveguide circuit, its manufacturing method and optical waveguide module having the optical waveguide circuit

Guided-wave circuit with optical characteristics adjusting plate method for producing it, and apparatus for producing optical characteristics adjusting plate

Dispersion resulting from phase and amplitude errors in arrayed-waveguide grating multiplexers-demultiplexers.

Optical waveguide circuit and optical waveguide module having the optical waveguide circuit

Optical circuit parts