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.

Methods and systems for a low-loss optical Y-Junction power splitter are disclosed and may include a semiconductor die having an optical Y-junction. The optical Y-junction may comprise an input waveguide, two or more output waveguides, a taper region and a step feature. The input waveguide and the taper region may include a smooth transition between the input waveguide and the taper region, and the step feature may be between the taper region and the output waveguides. The semiconductor die may receive an optical signal in the input waveguide, and communicate substantially equal power optical signals to the output waveguides. The semiconductor die may comprise a photonically-enabled silicon CMOS integrated circuit. An optical signal may be received in each of the output waveguides and a summed output signal may be communicated to the input waveguide. The step feature may extend in a direction perpendicular to an axis of the output waveguides.

An optical fiber combiner comprising a coupling device having an input surface area, and you A.sub.in, and an output surface area, A.sub.out, wherein the input surface area A.sub.in is greater than the output surface area A.sub.out, and a plurality of optical fibers each having an input surface and an output surface, wherein the output surfaces of the plurality of optical fibers are coupled to the coupling device, wherein the coupling device combines optical power emitted by the plurality of optical fibers.

A mode-matched waveguide Y-junction with balanced or unbalanced splitting comprises an input waveguide, expanding from an input end to an output end, for expanding the input beam of light along a longitudinal axis; first and second output waveguides extending from the output end of the input waveguide separated by a gap. Ideally, each of the first and second output waveguides includes an initial section capable of supporting a fundamental super mode, and having an inner wall substantially parallel to the longitudinal axis, and a mode splitting section extending from the initial section at an acute angle to the longitudinal axis.

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.

A semiconductor device may include a semiconductor wafer, and a reference circuit carried by the semiconductor wafer. The reference circuit may include optical DUTs, a first set of photodetectors coupled to outputs of the optical DUTs, an optical splitter coupled to inputs of the optical DUTs, and a second set of photodetectors coupled to the optical splitter. The optical splitter is to be coupled to an optical source and configured to transmit a reference optical signal to the first set of photodetectors via the optical DUTs and the second set of photodetectors.

A fiber optic connection device having a casing with a first end and a second end is disclosed. An optical splitter is positioned in the casing and has an input proximal to the first end of the casing and an output proximal to the second end of the casing. A first optical interface is located adjacent to the first end and is in optical communication with the input of the optical splitter. The first optical interface includes a first optical fiber interconnection point. A second optical interface is located adjacent the second end of the casing and is in optical communication with the output of the optical splitter. The second optical interface includes a second optical fiber interconnection point. In some embodiments, the casing may provide protection from environmental elements.

An optical testing circuit on a wafer includes an optical input configured to receive an optical test signal and photodetectors configured to generate corresponding electrical signals in response to optical processing of the optical test signal through the optical testing circuit. The electrical signals are simultaneously sensed by a probe circuit and then processed. In one process, test data from the electrical signals is simultaneously generated at each step of a sweep in wavelength of the optical test signal and output in response to a step change. In another process, the electrical signals are sequentially selected and the sweep in wavelength of the optical test signal is performed for each selected electrical signal to generate the test data.

An optical device. In some embodiments, the optical device includes a first interface; a second interface; a first plurality of waveguides, at the first interface; a second plurality of waveguides, at the second interface; and a free propagation region. A first waveguide of the first plurality of waveguides has a width at least 20% greater than a second waveguide of the first plurality of waveguides.

An optical testing circuit on a wafer includes an optical input configured to receive an optical test signal and photodetectors configured to generate corresponding electrical signals in response to optical processing of the optical test signal through the optical testing circuit. The electrical signals are simultaneously sensed by a probe circuit and then processed. In one process, test data from the electrical signals is simultaneously generated at each step of a sweep in wavelength of the optical test signal and output in response to a step change. In another process, the electrical signals are sequentially selected and the sweep in wavelength of the optical test signal is performed for each selected electrical signal to generate the test data.