Abstract: It is provided a laser arrangement, having an electro-absorption-modulated laser, having a laser section and an electro-absorption modulator section; a current source for supplying the laser section with current; a DC voltage source that is arranged in addition to the current source and can be used to apply DC voltage to a diode structure of the electro-absorption modulator section; a driver with which an RF signal is able to be fed to the laser; and an electrical connection via which the driver is connected to the laser. The electrical connection provides a direct current connection between the driver and the laser such, and the driver is configured such, that a photocurrent that is generated in the electrode-absorption modulator section of the laser by illumination with light of the laser section at least partially flows to the driver and at least contributes to the energy supply of the driver.

Abstract: the laser arrangement (1) is configured such that the electrical connection (14) provides a direct current connection between the driver (13) and the laser (11) such that a photocurrent (Iphoto) that is generated in the electrode-absorption modulator section (112) of the laser (11) by illumination with light of the laser section (111) at least partially flows to the driver (13) and at least contributes to the energy supply of the driver (13).

Abstract: An electro-optical modulator is provided. The modulator comprises a first and a second optical waveguide, at least one first capacitance, via which a voltage can be applied to a light-guiding region of the first optical waveguide, at least one second capacitance, via which a voltage can be applied to a light-guiding region of the second optical waveguide, an electrically conductive region, via which the first and second capacitances are electrically connected to one another, and a feed line to the electrically conductive region, via which feed line a DC voltage can be applied to the electrically conductive region, wherein the feed line is constituted such that it represents an electrical resistance connected in parallel with the second capacitance, and a compensation resistance connected in parallel with the first capacitance and serving for reducing transients in a voltage profile on the first and second capacitances during the operation of the modulator.

Abstract: An electro-optical modulator is provided. The modulator comprises a first and a second optical waveguide, at least one first capacitance, via which a voltage can be applied to a light-guiding region of the first optical waveguide, at least one second capacitance, via which a voltage can be applied to a light-guiding region of the second optical waveguide, an electrically conductive region, via which the first and second capacitances are electrically connected to one another, and a feed line to the electrically conductive region, via which feed line a DC voltage can be applied to the electrically conductive region, wherein the feed line is constituted such that it represents an electrical resistance connected in parallel with the second capacitance, and a compensation resistance connected in parallel with the first capacitance and serving for reducing transients in a voltage profile on the first and second capacitances during the operation of the modulator.

Abstract: A terminating impedance circuit, which is thermally decoupled from a substrate, for an electroabsorption modulator, having a modulator capacitance includes a series resistance-emphasized RF delay line exhibiting an impedance distributed over its length, wherein the spatially distributed impedance has at least a predominant resistance per unit length, an inductance per unit length tuned to the modulator capacitance, and a parasitic capacitance per unit length, wherein the resistance per unit length takes the function of a terminating resistor, wherein furthermore the inductance per unit length, together with the modulator capacitance, forms a strongly damped resonant circuit which provides, together with the terminating impedance circuit, for a controlled increase in the frequency response of the electroabsorption modulator within an operating frequency range, and wherein, at least for radio-frequency signals, the parasitic capacitance per unit length is negligible relative to the modulator capacitance.

Abstract: A terminating impedance circuit, which is thermally decoupled from a substrate, for an electroabsorption modulator, having a modulator capacitance includes a series resistance-emphasized RF delay line exhibiting an impedance distributed over its length, wherein the spatially distributed impedance has at least a predominant resistance per unit length, an inductance per unit length tuned to the modulator capacitance, and a parasitic capacitance per unit length, wherein the resistance per unit length takes the function of a terminating resistor, wherein furthermore the inductance per unit length, together with the modulator capacitance, forms a strongly damped resonant circuit which provides, together with the terminating impedance circuit, for a controlled increase in the frequency response of the electroabsorption modulator within an operating frequency range, and wherein, at least for radio-frequency signals, the parasitic capacitance per unit length is negligible relative to the modulator capacitance.

Abstract: A circuit sets an output potential at a radio frequency (RF) output of a pin photoreceiver that includes an ohmic terminal resistor connected between a supply voltage and the RF output. The circuit includes a control loop with an ohmic replication resistor having a resistance approximately equal to a resistance of the ohmic terminal resistor. The control loop further includes a sub-circuit configured to measure a voltage difference across the ohmic replication resistor and to reproduce the voltage difference as the supply voltage at an output terminal of the control loop.

Abstract: The present invention relates to a device for creating and coherently detecting terahertz radiation, comprising a laser light source (1), a transmission antenna (2) that can be activated by the laser light source (1) for creating the terahertz radiation, and a receiver with a receiver antenna (3) that can be activated by the same laser light source (1), wherein the transmission antenna (2) comprises a photo diode as a light-sensitive element and the receiver antenna (3) a fast photo-conductor as a light-sensitive element. The invention further relates to a use of such a device for analyzing a sample.

Abstract: A photodetector arrangement with a photoreceiver which comprises a photodiode, a blocking capacitor for high frequency and a terminal resistance lying at the signal output of the photodiode, is suggested. The photodiode is connected to a first bias connection for the supply with a blocking voltage, and a second bias connection is connected to the terminal resistance for the control of the potential at the signal output. A further blocking capacitor is provided for the high-frequency-technological earthing of the terminal resistance.

Abstract: A circuit sets an output potential at a radio frequency (RF) output of a pin photoreceiver that includes an ohmic terminal resistor connected between a supply voltage and the RF output. The circuit includes a control loop with an ohmic replication resistor having a resistance approximately equal to a resistance of the ohmic terminal resistor. The control loop further includes a sub-circuit configured to measure a voltage difference across the ohmic replication resistor and to reproduce the voltage difference as the supply voltage at an output terminal of the control loop.

Abstract: The invention relates to a photodiode chip which has a great limit frequency and a junction from the active photodiode area of a photodiode mesa to the output pad of the high-frequency output of the photodiode chip. The aim of the invention is to further increase the bandwidth factor of photodiode chips. Said aim is achieved by establishing the connection from the photodiode mesa to the output pad by means of a high-resistance wire with impedance (Zleitung) which is spread across the length thereof and is at least as high as the load impedance (Zlast) effective at the output pad.

Abstract: A photodetector arrangement with a photoreceiver which comprises a photodiode, a blocking capacitor for high frequency and a terminal resistance lying at the signal output of the photodiode, is suggested. The photodiode is connected to a first bias connection for the supply with a blocking voltage, and a second bias connection is connected to the terminal resistance for the control of the potential at the signal output. A further blocking capacitor is provided for the high-frequency-technological earthing of the terminal resistance.

Abstract: The present invention relates to a device for creating and coherently detecting terahertz radiation, comprising a laser light source (1), a transmission antenna (2) that can be activated by the laser light source (1) for creating the terahertz radiation, and a receiver with a receiver antenna (3) that can be activated by the same laser light source (1), wherein the transmission antenna (2) comprises a photo diode as a light-sensitive element and the receiver antenna (3) a fast photo-conductor as a light-sensitive element. The invention further relates to a use of such a device for analyzing a sample.

Abstract: A waveguide-integrated photodiode for high bandwidths with a semi-insulating monomode supply waveguide monolithically integrated on a substrate, together with an overlying photodiode mesa structure having an electroconducting n-contact layer, an absorption layer, a p+-contact layer and a metallic p-contact, the refraction index of the n-contact layer being greater than the refraction index of the semi-insulating waveguide layer. Lengthening the n-contact layer by a predetermined length L in the direction of the supply waveguide in relation to the overlying layers correspondingly increases at least one factor of the product of quantum efficiency and bandwidth.

Abstract: The invention relates to a photodiode chip which has a great limit frequency and a junction from the active photodiode area of a photodiode mesa to the output pad of the high-frequency output of the photodiode chip. The aim of the invention is to further increase the bandwidth factor of photodiode chips. Said aim is achieved by establishing the connection from the photodiode mesa to the output pad by means of a high-resistance wire with impedance (Zleitung) which is spread across the length thereof and is at least as high as the load impedance (Zlast) effective at the output pad.

Abstract: A waveguide-integrated photodiode for high bandwidths with a semi-insulating monomode supply waveguide monolithically integrated on a substrate, together with an overlying photodiode mesa structure having an electroconducting n-contact layer, an absorption layer, a p+-contact layer and a metallic p-contact, the refraction index of the n-contact layer being greater than the refraction index of the semi-insulating waveguide layer. Lengthening the n-contact layer by a predetermined length L in the direction of the supply waveguide in relation to the overlying layers correspondingly increases at least one factor of the product of quantum efficiency and bandwidth.

Abstract: Apparatus for measuring the A.C. characteristics of a circuit element under test maintains a stable D.C. bias voltage across the component under test by sensing the difference between the output voltage of the D.C. bias voltage source and the voltage drop across the circuit element under test, to control the D.C. bias voltage applied and to compensate for variable voltage drops in the measurement circuit. The apparatus compensates both for the fixed resistance in the circuit and for the variable resistance due to changing the range resistor.