| 摘要 |
The interface device comprises a voltage-offset diode (DD) mounted between the output (32) of an upstream circuit (18) and the input of a downstream circuit (8), where the downstream circuit requires a d.c. polarization voltage higher than the upstream circuit and a relatively substantial polarization current which is a function of the power delivered by the downstream circuit. The characteristic of the voltage-offset diode (DD) is chosen so that the polarization voltage of the upstream circuit is offset by an amount corresponding substantially to the difference between the polarization voltages (VD,VL) of the upstream and the downstream circuits (18,8), respectively, and the polarization current of the downstream circuit is higher than the threshold current of the voltage-offset diode. The voltage-offset diode (DD) comprises a set of transistors whose drains and sources are connected together and the gates projections form contacts with the diode effect, which is of Schottky type. The development of each gate projection is about a few micrometres, and the total development of the voltage-offset diode is about several tns of micrometres. The downstream circuit comprises a laser diode which can emit wide-band super-high frequency signals, and is of low impedance, that is a few Ohms. The upstream circuit is in the form of a distributed amplifier having the role of low-impedance adapter, and comprises a set of amplifier cells (AB) mounted between a gate illne (LG), which is the input line, and a drain line (LD), which is the output line. The polarization current of the downstream circuit is about several tens of mA. The device also comprises a filter circuit (PD) for polarizing the output line, which is the second embodiment comprises transistors functioning in charge-saturation mode. |
