关于半导体光激射器工作电流范围的分析

本文直接利用阈值电流随温度变化的实验关系,通过解热传导方程,得到了连续及脉冲工作状态下起始工作电流、最大工作电流及临界阈值电流的定量结果,供研制参考。其中全面地考虑了结内及体内发热的贡献,后者可用一归一化等效体内发热电阻r来表征。连续工作状态的分析表明,体内发热的影响不可忽略。对脉冲工作状态的分析,分别考虑了脉冲宽度和重复频率的影响。指出:在兼顾功率和重复频率的情况下,脉冲工作比以取0.03左右为宜。当实际应用中对重复频率要求不高时,为了提高功率,取重复周期比二极管热弛豫时间约大3倍比较合适。如果要求重复频率很高,则器件性能主要由脉冲工作比决定。文中利用所得结果结合实例进行了讨论,并讨论了脉冲工作情况由于结温变化所导致的发射频谱展宽效应。

AN ANALYSIS FOR THE OPERATION CURRENT RANGE OF INJECTION LASER

An analysis is made for the initial current, the operation current limit, and the critical threshold current of the injection laser at continuous and pulse operation conditions. Both the heat generated at junction and bulk heat generation have been taken into account simultaneously, the later can be characterized with a normalized equivalent bulk heating resistance r. For the continuous operation case, it is shown that the bulk heat generation cannot often be neglected. In the analysis for pulse operation case, the effect of pulse duration and that of repetition frequency have been considered respectively. It is indicated that when both the high power and high repetition frequency operation are desirable, it will be optimum to choose the duty cycle approach to 0.03. In some applications where the repetition frequency is not an important factor, to make the repetition period just three times larger than the thermal relaxation time of lasers is suitable. As the repetition frequency increased sufficiently, the performance of lasers is determined by the duty cycle mainly. Examples of the analysis applied to some typical cases have been illustrated and the emission spectral band broadening originated from junction temperature variation during pulse operation is briefly discussed.