Abstract: A front end for a broadband optical receiver is disclosed which includes a monolithic integrated Darlington circuit with bipolar transistors (T1, T2). This Darlington circuit is a simple integrated amplifier (OP) developed for UHF application in the range between 0 and 2 GHz. By connecting a suitable transimpedance resistor (R.sub.T) across the Darlington circuit, an improvement in linearity is obtained such that the Darlington circuit can be used together with an avalanche photodiode (APD) in the 0- to 5-GHz frequency range, and together with PIN diodes in short-and medium-length optical tansmission links.

Abstract: A problem encountered in the design of preamplifiers of optical receivers, e.g., of so-called transimpedance amplifiers, is to achieve both a wide bandwidth and high sensitivity. The invention solves this problem primarily by a specific implementation and placement of the feedback resistor in the transimpedance amplifier type, and of the load resistor in the high-impedance amplifier type which permit a high resistance value and very low series and shunt capacitances. The resistor consists of a resistive strip (1) and conductive strips (2, 3) deposited on a substrate, the conductive strips extending parallel to the resistive strip and each having one end connected to one end of the resistive strip. To reduce shunt capacitances, the substrate is located at a distance from the metallic amplifier case and from the amplifier board.