Abstract: An optically modulated signal is generated for use in transporting data by generating a so-called sub-carrier modulated optical signal and, then, vector modulating the sub-carrier modulated optical signal to yield the desired modulated optical signal for transmission. The vector modulation includes a phase component and an amplitude component. In one specific embodiment of the invention, an apparatus for use in generating a modulated optical signal includes a generator to generate a sub-carrier modulated optical signal including an optical carrier and at least one sub-carrier and an analog vector modulator coupled to receive both the sub-carrier modulated optical signal from the generator and a data signal. The analog vector modulator generates an output optical signal by phase modulating and/or amplitude modulating the sub-carrier of the received optical signal in response to the data signal.

Abstract: An optical digital-to-analog conversion is realized by employing either a continuous wave or pulsed laser optical signal. The laser optical signal is split into a plurality of mutually coherent optical beams, which are phase shift modulated by bits of a digital data sequence to be converted to an analog signal. The phase shift modulated optical beams are recombined to realize the desired digital-to-analog converted optical signal.

Abstract: A transceiver includes a transmitter, a receiver, and an electrical feedback line. The transmitter has a quadrature-modulator and is configurable to compensate inphase/quadrature phase imbalances produced by hardware of the transmitter. The quadrature-modulator is configured to quadrature-modulate a carrier wave. The receiver has a quadrature-demodulator and is configurable to compensate for inphase/quadrature phase imbalances produced by hardware in the receiver. The quadrature-demodulator is configured to demodulate a quadrature-demodulated carrier. The electrical feedback line connects an output of the transmitter to an input of the receiver.

Abstract: An apparatus includes a spiral conductor, a first electronic device, and a second electronic device. The spiral conductor has first and second ends. The first end is a first port of the conductor. An intermediate portion of the conductor is a second port of the conductor. The second end is a third port of the conductor. The first electronic device has a first terminal connected to the first port and has a second terminal connected to the second port. The first electronic device is capable of carrying a current between the first and second terminals. The second electronic device has a third terminal that operates as a current source or sink. The third terminal is connected to the third port.

Abstract: An adaptive optical parallel equalizer architecture is based on a controllable optical FIR filter device to realize an optical FIR (finite-impulse-response) filter including a plurality of coefficient taps in order to have independent control of each optical FIR filter coefficient. A unique adaptive opto-electronic LMS (least mean square) process is utilized to generate an electronic error signal utilized to control the plurality of parallel tap coefficients of the optical parallel equalizer. The electronic error signal is used as the optimization criterion because the electronic signal after photo-detection is needed to achieve any measurable performance in terms of bit error rate (BER). In a specific embodiment, the controllable optical parallel FIR filter is realized by employing an optical vector modulator.

Abstract: An adaptive optical parallel equalizer architecture is based on a controllable optical modulator device to realize an optical FIR (finite-impulse-response) filter including a plurality of coefficient taps in order to have independent control of each optical FIR filter coefficient. A unique adaptive opto-electronic LMS (least mean squares) process is utilized to generate an electronic error signal utilized to control the plurality of parallel tap coefficients of the optical parallel equalizer. The electronic error signal is used as the optimization criterion because the electronic signal after photo-detection is needed to achieve any measurable performance in terms of bit error rate (BER). In a specific embodiment, the controllable optical parallel FIR filter is realized by employing an optical vector modulator.

Abstract: Apparatus comprising: a first compound semiconductor composition layer doped to have a first charge carrier polarity; a second compound semiconductor composition layer doped to have a second charge carrier polarity and located on the first layer; a third compound semiconductor composition layer doped to have the first charge carrier polarity and located on the second layer; a base electrode on the second layer; and a spacer ring interposed between and defining a charge carrier access path distance between the base electrode and the third layer, the path distance being within a range of between about 200 ? and about 1000 ?. Techniques for making apparatus. Apparatus is useful as a heterobipolar transistor, particularly for high frequency applications.

Abstract: An apparatus includes an optical splitter, an optical combiner, first and second optical paths, and a digital signal generator. The optical splitter has an input port and first and second output ports. The optical combiner has first and second input ports and an output port. The first optical path couples the first output port of the splitter to the first input port of the combiner. The second optical path couples the second output port of the splitter to the second input port of the combiner. Each optical path includes an electro-optical phase shifter, and one of the optical paths includes an electro-optical attenuator. The digital signal generator is configured to apply binary-valued voltage signals to control inputs of the phase shifters and the attenuator.

Abstract: An optical digital-to-analog conversion is realized by employing either a continuous wave or pulsed laser optical signal. The laser optical signal is split into a plurality of mutually coherent optical beams, which are phase shift modulated by bits of a digital data sequence to be converted to an analog signal. The phase shift modulated optical beams are recombined to realize the desired digital-to-analog converted optical signal.

Abstract: A method for fabricating a bipolar transistor includes forming a vertical sequence of semiconductor layers, forming an implant mask on the last formed semiconductor layer, and implanting dopant ions into a portion of one or more of the semiconductor layers. The sequence of semiconductor layers includes a collector layer, a base layer that is in contact with the collector layer, and an emitter layer that is in contact with the base layer. The implanting uses a process in which the implant mask stops dopant ions from penetrating into a portion of the sequence of layers.

Abstract: A method for fabricating a bipolar transistor includes forming a vertical sequence of semiconductor layers, forming an implant mask on the last formed semiconductor layer, and implanting dopant ions into a portion of one or more of the semiconductor layers. The sequence of semiconductor layers includes a collector layer, a base layer that is in contact with the collector layer, and an emitter layer that is in contact with the base layer. The implanting uses a process in which the implant mask stops dopant ions from penetrating into a portion of the sequence of layers.

Abstract: A method for transmitting digital data includes splitting a coherent optical carrier having a subcarrier into mutually coherent optical carriers, producing corresponding sequences of phase shifts in each of the mutually coherent optical carriers, and then, interfering the mutually coherent optical carriers. The interfering produces an output optical carrier whose subcarrier has modulated inphase and quadrature components with a corresponding sequence of pairs of values. The pairs of values of the modulated inphase and quadrature phase components produced by the interfering correspond to a sequence of coordinate pairs for the signal points the 4-PSK 2D, 16-QAM 2D, or 16-PSK 2D constellation.

Abstract: A method for fabricating a bipolar transistor includes forming collector, base, and emitter semiconductor layers on a substrate such that the layers form a vertical sequence with respect to an adjacent surface of the substrate. The method includes etching away a portion of a top one of the semiconductor layers to expose a portion of the base semiconductor layer and then, growing semiconductor on the exposed portion of the base layer. The top one of the semiconductor layers is the layer of the sequence that is located farthest from the substrate. The growing causes grown semiconductor to laterally surround a vertical portion of the top one of the semiconductor layers.

Abstract: Microelectronic apparatus having protection against high frequency crosstalk radiation, comprising: a planar insulating substrate; an active semiconductor electronic device located over a first region of the insulating substrate; and a doped semiconductor located in a second region of the insulating substrate substantially surrounding the first region. Apparatus further comprising a dissipative conductor overlaying and adjacent to the doped semiconductor. Apparatus additionally comprising metallic test probe contacts making electrical connections with the active semiconductor electronic device. Application of the apparatus to dissipate crosstalk radiation having a center frequency within a range between about 1 gigahertz and about 1,000 gigahertz. Methods for making the apparatus.

Abstract: A driver, e.g., for use with electro-optic (E/O) modulators. The driver is configured to generate a driving signal based on an electronic NRZ input data signal and an input clock signal. The driver converts the NRZ input data signal to an RZ format and produces an amplified RZ signal that can be applied to an E/O modulator. The amplification gain of the driver is adjustable to enable interfacing with different modulators. In one embodiment of the invention, the driving signal is generated based on a comparison between the NRZ input data signal and an offset clock signal generated from the input clock signal. The width of pulses in the driving signal, e.g., corresponding to logical “ones,” may be tuned by, e.g., changing the DC offset of the clock signal. The driver may be implemented as an ASIC configured to operate at the data rate of, e.g., 10 GBit/s.

Abstract: An optically modulated signal is generated for use in transporting data by generating a so-called sub-carrier modulated optical signal and, then, vector modulating the sub-carrier modulated optical signal to yield the desired modulated optical signal for transmission. The vector modulation includes a phase component and an amplitude component. In one specific embodiment of the invention, the vector modulation is effected by splitting the sub-carrier modulated optical signal comprising a carrier and an at least one unmodulated sub-carrier into a plurality of similar optical signals, phase modulating the carrier of each of the similar optical signals with the data and delaying the resulting optical signals in a prescribed manner relative to one another. Then, the “delayed” signals are combined to yield the signal comprising the vector modulated sub-carrier modulated optical signal to be transmitted. Wherein a signal can be “delayed” by a zero (0) delay interval.

Abstract: A method for fabricating a bipolar transistor includes forming a vertical sequence of semiconductor layers, forming an implant mask on the last formed semiconductor layer, and implanting dopant ions into a portion of one or more of the semiconductor layers. The sequence of semiconductor layers includes a collector layer, a base layer that is in contact with the collector layer, and an emitter layer that is in contact with the base layer. The implanting uses a process in which the implant mask stops dopant ions from penetrating into a portion of the sequence of layers.

Abstract: A latch chain having improved input voltage sensitivity. The chain includes a first latch, an amplifier, and a second latch connected in series. The second latch is a conventional latch. The first latch is modified to have a higher sensitivity and lower output voltage swing than conventional latches. The modified latch includes a pair of matched output transistors that generate output voltages and a pair of matched biasing circuits to bias the bases of the output transistors with bias voltages. A sample stage is connected so as to apply first biasing currents to one of the biasing circuits in response to input voltages applied to the first latch during the sample period. In addition, a hold stage is connected so as to apply second biasing currents to the biasing circuits during a hold period. The sample and hold stages are configured to apply different voltage differences between the bases of the output transistors.

Abstract: Disclosed are a method of making GaAs-based enhancement-type MOS-FETs, and articles (e.g., GaAs-based ICs) that comprise such a MOS-FET. The MOS-FETs are planar devices, without etched recess or epitaxial re-growth, with gate oxide that is primarily Ga2O3, and with low midgap interface state density (e.g., at most 1×1011 cm−2 eV−1 at 20° C.). The method involves ion implantation, implant activation in an As-containing atmosphere, surface reconstruction, and in situ deposition of the gate oxide. In preferred embodiments, no processing step subsequent to gate oxide formation is carried out above 300° C. in air, or above about 700° C. in UHV. The method makes possible fabrication of planar enhancement-type MOS-FETs having excellent characteristics, and also makes possible fabrication of complementary MOS-FETs, as well as ICs comprising MOS-FETs and MES-FETs.

Abstract: A circuit that increases the efficiency of a radio frequency mobile telephone unit is disclosed. When the signal strength between the base station and the mobile unit is below a predetermined signal strength level, the power amplifier is turned on and the transmitter circuit of the mobile unit fully amplifies the RF signal. However, when the signal strength between the mobile telephone unit and the base station is above a predetermined signal strength level, the power amplifier is deactivated and bypassed from the transmitter circuitry, thereby conserving the battery power of the mobile unit.