Abstract:
Circuit arrangement (CR; CR') for receiving multilevel optical signals (SI) from at least one optical guide (GU), said multilevel signals resulting from superposing a high speed data signal and a low speed data signal, said circuit arrangement (CR; CR') comprising: • - at least one light-receiving component (PD) for converting the optical signals (SI) into electrical current signals (Ipp), • - at least one transimpedance amplifier (TA), being provided with the electrical current signals (I pp) from the light-receiving component (PD), • - at least one automatic gain controller (AG) for controlling the gain or transimpedance (R) of the transimpedance amplifier (TA), in particular in order to keep the amplitude of the output (V out- data-analog) of the transimpedance amplifier (TA) to a desired, for example constant, level for different levels of the electrical current signals (I PD), • - at least one integrator (IN) in a feedback path (FP), said integrator (IN) generating a control signal (Vint), • - at least one voltage-controlled current source (CS), being provided with the control signal (V jnt) from the integrator (IN), • - at least one limiter (LI) acting as a comparator and generating in its output a logic level for positive or negative voltages in its input, • - at least one second transimpedance amplifier (TA2) arranged in parallel to the transimpedance amplifier (TA), and • - at least one automatic offset controller (AO) for setting the voltage (Voffset) for the second transimpedance amplifier (TA2).
Abstract:
Circuit arrangement (CR; CR') for receiving multilevel optical signals (SI) from at least one optical guide (GU), said multilevel signals resulting from superposing a high speed data signal and a low speed data signal, said circuit arrangement (CR; CR') comprising: • - at least one light-receiving component (PD) for converting the optical signals (SI) into electrical current signals (Ipp), • - at least one transimpedance amplifier (TA), being provided with the electrical current signals (I pp) from the light-receiving component (PD), • - at least one automatic gain controller (AG) for controlling the gain or transimpedance (R) of the transimpedance amplifier (TA), in particular in order to keep the amplitude of the output (V out- data-analog) of the transimpedance amplifier (TA) to a desired, for example constant, level for different levels of the electrical current signals (I PD), • - at least one integrator (IN) in a feedback path (FP), said integrator (IN) generating a control signal (Vint), • - at least one voltage-controlled current source (CS), being provided with the control signal (V int) from the integrator (IN), • - at least one limiter (LI) acting as a comparator and generating in its output a logic level for positive or negative voltages in its input, • - at least one second transimpedance amplifier (TA2) arranged in parallel to the transimpedance amplifier (TA), and • - at least one automatic offset controller (AO) for setting the voltage (Voffset) for the second transimpedance amplifier (TA2).
Abstract:
The present invention includes a semiconductor epitaxial structure optimized for photoconductive free space terahertz generation and detection; and amplifier circuits for photoconductively sampled terahertz detection which may employ the optimized epitaxial structures.
Abstract:
A resonant cavity with tunable nanowire. The resonant cavity includes a substrate (114/116/230/330/430/530/630). The substrate is coupleable to an optical resonator structure (110/210/310/410/510/610). The resonant cavity also includes a plurality of nanowires (120/220/320/420/520/620) formed on the substrate. The plurality of nanowires is actuated (122/222/322/422/522/623) in response to an application of energy.