Abstract: A phased array antenna includes an antenna array substrate having a plurality of antenna elements. At least two beamformers are coupled to the plurality of antenna elements. At least two filters support different frequency bands and are respectively coupled to the at least two beamformers. A frequency converter is coupled to the at least two filters, the frequency converter including one intermediate frequency (IF) port and at least two radio frequency (RF) ports. The one IF port of the frequency converter is configured to support the at least two beamformers via the at least two RF ports. A first beamformer of the at least two beamformers is coupled to a first filter of the at least two filters to form a first beam in a direction different than a second beamformer of the first two beamformers coupled to a second filter of the at least two filters.

Abstract: A phased array antenna includes an antenna array substrate having a plurality of antenna elements. At least two beamformers are coupled to the plurality of antenna elements. At least two filters support different frequency bands and are respectively coupled to the at least two beamformers. A frequency converter is coupled to the at least two filters, the frequency converter including one intermediate frequency (IF) port and at least two radio frequency (RF) ports. The one IF port of the frequency converter is configured to support the at least two beamformers via the at least two RF ports. A first beamformer of the at least two beamformers is coupled to a first filter of the at least two filters to form a first beam in a direction different than a second beamformer of the first two beamformers coupled to a second filter of the at least two filters.

Abstract: An optical module includes: a butterfly-type optical device including a body that contains a heating element in an interior space, a lid body that puts a lid on the interior space, and a plurality of pins; a substrate including a connecting surface to which the plurality of pins are connected; and a heat-dissipating component arranged to the connecting surface side, wherein the optical device is connected to the connecting surface with a heat-dissipating surface, of a part that has been arranged with the heating element, oriented to the heat-dissipating component side, and with a gap provided to a side of the lid body opposite to a side of the interior space.

Abstract: An optical module includes: a butterfly-type optical device including a body that contains a heating element in an interior space, a lid body that puts a lid on the interior space, and a plurality of pins; a substrate including a connecting surface to which the plurality of pins are connected; and a heat-dissipating component arranged to the connecting surface side, wherein the optical device is connected to the connecting surface with a heat-dissipating surface, of a part that has been arranged with the heating element, oriented to the heat-dissipating component side, and with a gap provided to a side of the lid body opposite to a side of the interior space.

Abstract: An optical modulation system has a function to compensate an operating point drift, which occurs in an MZ optical modulator, by carrying out feedback control with use of a low frequency signal. A judgment section judges stability of feedback control. In a case where the feedback control is determined to be unstable, a low frequency signal generating section switches a frequency of the low frequency signal from a first frequency to a second frequency.

Abstract: A control apparatus for an external modulator that modulates light emitted from a light source based on an input signal, the control apparatus comprises: a low-frequency signal generating device that generates and outputs a low-frequency signal having a predetermined frequency; a signal superimposing device that superimposes a first modulation signal, which is the input signal on the low-frequency signal, to make a second modulation signal, and applies this second modulation signal to the external modulator; a low-frequency signal detecting device that detects the low-frequency signal component from an optical output of the external modulator, compares a phase of this detected low-frequency signal with a phase of a low-frequency signal output from the low-frequency signal generating device, and outputs a signal according to a phase difference; an operating point control device that controls based on an output signal of the low-frequency signal detecting device, so as to compensate for operating point drift of

Abstract: A control apparatus for an external modulator that modulates light emitted from a light source based on an input signal, the control apparatus comprises: a low-frequency signal generating device that generates and outputs a low-frequency signal having a predetermined frequency; a signal superimposing device that superimposes a first modulation signal, which is the input signal on the low-frequency signal, to make a second modulation signal, and applies this second modulation signal to the external modulator; a low-frequency signal detecting device that detects the low-frequency signal component from an optical output of the external modulator, compares a phase of this detected low-frequency signal with a phase of a low-frequency signal output from the low-frequency signal generating device, and outputs a signal according to a phase difference; an operating point control device that controls based on an output signal of the low-frequency signal detecting device, so as to compensate for operating point drift of

Abstract: Threshold setting apparatus controls a relative relation in DC level between a baseband signal produced by processing a received signal and a threshold for use in identifying serial data from the baseband signal. The apparatus includes a waveform distortion estimating circuit and a setting circuit. The waveform distortion estimating circuit estimates, based on the baseband signal, a relation between the center of the dynamic range of the baseband signal and a crossing point where a positive-going edge curve crosses a negative-going edge curve of an eye pattern formed by the baseband signal. The setting circuit adjustably sets either the threshold or the DC level of the baseband signal in dependence upon the relation estimated by the waveform distortion estimating circuit.

Abstract: Threshold setting apparatus controls a relative relation in DC level between a baseband signal produced by processing a received signal and a threshold for use in identifying serial data from the baseband signal. The apparatus includes a waveform distortion estimating circuit and a setting circuit. The waveform distortion estimating circuit estimates, based on the baseband signal, a relation between the center of the dynamic range of the baseband signal and a crossing point where a positive-going edge curve crosses a negative-going edge curve of an eye pattern formed by the baseband signal. The setting circuit adjustably sets either the threshold or the DC level of the baseband signal in dependence upon the relation estimated by the waveform distortion estimating circuit.