Abstract:
Disclosed are a Mach-Zehnder interferometric optical modulator and a method for manufacturing the same. The modulator includes first and second lower clad layers, a core layer, an upper clad layer, a waveguide, and electrodes. The waveguide may include an input waveguide, a waveguide divider, branch waveguides, and a waveguide combiner. Each of the branch waveguides includes first and second connection regions connected to the waveguide combiner and the waveguide divider, respectively, and a phase shift region having a cross-section of a reverse mesa structure that has an upper width that is the same as widths of the first and second connection regions and a lower width that is smaller than the widths of the first and second connection regions.
Abstract:
An apparatus for measuring performance of a coherent optical receiver includes a beam splitter splitting light into first and second paths, a first optical modulator modulating the first path light, a variable optical attenuator controlling an optical power of the first optical modulator, a first polarization controller transmitting a signal controlling polarization of an output of the variable optical attenuator to the coherent optical receiver, a second optical modulator modulating the second path light, a variable optical delay line delaying time of an output of the second optical modulator, a second polarization controller transmitting a signal controlling polarization of an output of the variable optical delay line to the coherent optical receiver, a network analyzer measuring performance of the coherent optical receiver and controlling the optical modulators, and a controller transmitting a control signal to the optical modulators.
Abstract:
Provided is a waveguide photodetector including a semiconductor substrate, a first optical waveguide and a second optical waveguide, which are sequentially laminated on the semiconductor substrate, in which each of the first optical waveguide and the second optical waveguide includes a first portion and a second portion, and the first portion extends from the second portion in a first direction parallel to a top surface of the semiconductor substrate, a refractive index matching layer disposed on the second portion of the second optical waveguide, a clad layer disposed on the refractive index matching layer, and an absorber disposed between the refractive index matching layer and the clad layer. Here, the second optical waveguide has a first conductive-type, the clad layer has a second conductive-type opposite to the first conductive-type, and the refractive index matching layer includes a first semiconductor layer that is an intrinsic semiconductor layer.
Abstract:
An optical alignment device according to an embodiment of the inventive concept includes an optical alignment plate having a first hole and at least one second hole, in which the first hole and the second hole pass through the optical alignment plate, and an optical detection element disposed on the optical alignment plate. Here, the optical detection element includes a substrate having a first surface and a second surface, which face each other, a lens disposed on the first surface, and an optical sensor disposed on the second surface, and the optical detection element vertically overlaps the first hole and the second hole. The lens is exposed to the outside by the first hole, and the second hole is connected with a vacuum suction unit to fix the optical detection element to the optical alignment plate.
Abstract:
Provided is a method of measuring signal transmission time difference of a measuring device. The measuring device according to embodiments, by measuring a skew on two optical paths through signal delays of sufficient sizes for skew measurement on the optical paths, even a skew having a minute size can be measured within a measurable range.
Abstract:
Disclosed are a Mach-Zehnder interferometric optical modulator and a method for manufacturing the same. The modulator includes first and second lower clad layers, a core layer, an upper clad layer, a waveguide, and electrodes. The waveguide may include an input waveguide, a waveguide divider, branch waveguides, and a waveguide combiner. Each of the branch waveguides includes first and second connection regions connected to the waveguide combiner and the waveguide divider, respectively, and a phase shift region having a cross-section of a reverse mesa structure that has an upper width that is the same as widths of the first and second connection regions and a lower width that is smaller than the widths of the first and second connection regions.
Abstract:
An optical waveguide structure includes a substrate and a core structure disposed on the substrate. The substrate includes a first waveguide region, a second waveguide region, and a transition region between the first waveguide region and the second waveguide region. The core structure includes first core segments arranged in a first direction and a second direction crossing the first direction on the transition region. The core structure includes second core segments arranged in the first direction and the second direction on the second waveguide region. The first direction and the second direction are parallel to a top surface of the substrate.
Abstract:
Provided is an apparatus and method for measuring IQ imbalance, and in particular, is an apparatus and method for measuring IQ imbalance for an optical receiver. The apparatus for measuring IQ imbalance for an optical receiver includes a light generating unit generating optical and reference signals to provide the optical and reference signals to an optical receiver, a graph creating unit creating a Lissajous figure by using an in-phase (I) signal and a quadrature-phase (Q) signal output from the optical receiver in response to the optical and reference signals, and a calculating unit calculating IQ imbalance for the optical receiver with reference to the Lissajous figure.