论文标题
谐振 - 触发二二极管Terahertz发射器的直接调节的固有频率限制和外部反馈注射的效果
Intrinsic Frequency Limit of Direct Modulation of Resonant-Tunneling-Diode Terahertz Emitters and Effect of External Feedback Injection
论文作者
论文摘要
谐振触发二极管（RTD）Terahertz（THZ）发射器的输出功率可以通过类似于半导体激光器的偏置调制来调节。该属性对于THZ波的应用在无线通信和雷达上很有用。在本文中，我们理论上使用RTD-THZ振荡器的等效电路分析了输出响应的调制频率依赖性。结果表明，RTD中的调制的固有截止频率存在，该频率与向振荡器提供调制信号的外部电路无关。该截止频率取决于RTD的电容给出的时间常数除以振荡器的负差分电导率减去损耗电导的绝对值，对于典型的RTD-THZ振荡器而言约为100 GHz。我们还分析了外部反馈注入对调制特征的影响。如果调制频率的周期等于反馈的往返时间的积分倍数，则取决于输出的调制响应中的倾斜或峰会，具体取决于输出和反馈中的THZ载体组件是相位还是相位。我们还讨论了在短往返时间中反馈通过反馈增加截止频率的可能性。
Output power of resonant-tunneling-diode (RTD) terahertz (THz) emitters can be modulated by the bias modulation similar to a semiconductor laser. This property is useful for applications of the THz waves to wireless communications and radars. In this paper, we theoretically analyze the modulation-frequency dependence of the output response using an equivalent circuit of the RTD-THz oscillator. It is shown that there exists an intrinsic cutoff frequency of modulation in RTD, which is independent of the external circuit that supplies the modulation signal to the oscillator. This cutoff frequency is determined by the time constant given by the capacitance of RTD divided by the absolute value of negative differential conductance minus loss conductance of the oscillator, and is about 100 GHz for typical RTD-THz oscillators. We also analyze the effect of external feedback injection on the modulation characteristics. If the period of the modulation frequency is equal to an integral multiple of the round-trip time of the feedback, a dip or peak occurs in the modulation response of the output, depending on whether the THz carrier components in the output and the feedback are in phase or out of phase. We also discuss the possibility of increase in cutoff frequency by the feedback with short round-trip time.
