Aspects of the present disclosure are directed to wavelength division multiplexing systems comprising arrays of spectrally selective devices that are arranged on a substrate to compensate for perturbations of the spectral characteristics of the devices due to factors such as temperature non-uniformity, inherent spectral non-uniformity, and the like. As a result, shifts in the center wavelengths and/or changes in the wavelength spacing for the wavelength channels of a WDM system due to such perturbations are mitigated. In some embodiments, an array of spectrally selective devices is arranged on a substrate such that their respective wavelength channels are not linearly correlated with their physical position within the array, enabling the devices to be arranged in pairs that are subject to substantially the same environmental conditions and/or operate on nearly the same spectral range.

An optical module includes a base having a first surface, a board having a second surface and a third surface, an optical circuit element having a fourth surface, a fifth surface and two ports, and an array lens. The first surface is joined to the second surface by a first solder. The third surface has a first metallic pattern and a second metallic pattern that are joined to the fourth surface by a second solder. The array lens is fixed onto the first surface of the base so as to be optically coupled to the two ports provided at one end of the optical circuit element in the first direction. The first metallic pattern is formed closer than the second metallic pattern to the one end of the optical circuit element in the first direction and is formed between the two ports in the second direction.

An optical transceiver may include an optical receptacle configured to input or output an optical signal, a first planar lightwave circuit through which the optical signal travels, an arrayed waveguide grating connected to the first planar lightwave circuit, and a first spot size converter connecting the optical receptacle and the first planar lightwave circuit.

A dependency of a characteristic of an optical circuit on an optical signal intensity occurring due to input of a high intensity optical signal is reduced in a waveguide type optical interferometer circuit. The waveguide type optical interferometer circuit is a waveguide type optical interferometer circuit formed in one plane, and includes an input waveguide, an optical branching unit, an optical coupling unit, an output waveguide, and optical waveguides having different lengths from each other and being interposed between the optical branching unit and the optical coupling unit. A light intensity compensating region is formed on an optical path extending from the optical branching unit to the optical coupling unit, and the light intensity compensating region is formed by using a light intensity compensating material having a light intensity coefficient different from a light intensity coefficient of an optical distance relative to an incident light intensity in the optical path.

Aspects of the present disclosure are directed to wavelength division multiplexing systems comprising arrays of spectrally selective devices that are arranged on a substrate to compensate for perturbations of the spectral characteristics of the devices due to factors such as temperature non-uniformity, inherent spectral non-uniformity, and the like. As a result, shifts in the center wavelengths and/or changes in the wavelength spacing for the wavelength channels of a WDM system due to such perturbations are mitigated. In some embodiments, an array of spectrally selective devices is arranged on a substrate such that their respective wavelength channels are not linearly correlated with their physical position within the array, enabling the devices to be arranged in pairs that are subject to substantially the same environmental conditions and/or operate on nearly the same spectral range.

An optical waveguide element includes: a cladding portion made of silica-based glass; and a plurality of optical waveguides positioned in the cladding portion and made of silica-based glass in which ZrO.sub.2 crystal particles are dispersed. The optical waveguide element is a planar lightwave circuit. The plurality of optical waveguides configure an arrayed waveguide grating element.

An arrayed waveguide grating. The arrayed waveguide grating (145) includes two star couplers (130, 150) and an array of waveguides (215, 225) connecting the star couplers. The array of waveguides of the arrayed waveguide grating may have a T-shaped geometry making possible an arrayed waveguide grating with an arbitrarily large free spectral range in a compact form factor. Different materials may be used in the optical paths to reduce the temperature dependence of the characteristics of the arrayed waveguide grating.

A return loss in an optical connector connection structure according to a lens scheme is reduced. An optical connector (10) according to this disclosure, includes: a plurality of optical fibers (18) arranged in an array; and a lens array plate (14) that includes a first principal surface (40) with a plurality of lenses (44) corresponding to the respective optical fibers being formed on this surface, and a second principal surface (41) joined to end faces (180) of the optical fibers so as to be opposed to the first principal surface and optically coupled to the optical fibers to which the respective lenses correspond, wherein at least one of the end faces of the optical fibers and the second principal surface is inclined from a plane (182) perpendicular to optical axes (181) of the optical fibers.

A substrate of an optical electrical module is provided. The substrate includes a plurality of accommodating grooves and a reflective groove. The accommodating grooves respectively extend along a first direction. The reflective groove is connected with the accommodating grooves and extends along a second direction perpendicular to the first direction.

With a wavelength conversion device based on a nonlinear optical effect, when arrayed waveguides including an intended nonlinear waveguide are fabricated, unwanted slab waveguides are inevitably formed. The slab waveguides can cause an erroneous measurement in the selection of a waveguide having desired characteristics from the arrayed waveguides. The erroneous measurement can lead to redoing steps for fabricating the wavelength conversion device and a decrease in the yield and inhibit the evaluation of the characteristics in selection of the waveguide and the subsequent fabrication of the wavelength conversion device from being efficiently performed. A wavelength conversion device according to the present invention includes a plurality of waveguides formed on a substrate, and a plurality of slab waveguides that are arranged substantially in parallel with and spaced apart from the plurality of waveguides, and a guided light attenuator is formed in each of the slab waveguides. The guided light attenuators allow efficient selection of a waveguide having desired optical characteristics from the plurality of waveguides. The light attenuation by the guided light attenuators can be changed in steps for fabricating the wavelength conversion device.