Rymanov Vitaly, Stöhr Andreas, Dülme Sebastian, Tekin Tolga
Opt Express. 2014 Apr 7;22(7):7550-8. doi: 10.1364/OE.22.007550.
We report on a novel triple transit region (TTR) layer structure for 1.55 μm waveguide photodiodes (PDs) providing high output power in the millimeter wave (mmW) regime. Basically, the TTR-PD layer structure consists of three transit layers, in which electrons drift at saturation velocity or even at overshoot velocity. Sufficiently strong electric fields (>3000 V/cm) are achieved in all three transit layers even in the undepleted absorber layer and even at very high optical input power levels. This is achieved by incorporating three 10 nm thick p-doped electric field clamp layers. Numerical simulations using the drift-diffusion model (DDM) indicate that for optical intensities up to ~500 kW/cm(2), no saturation effects occur, i.e. the electric field exceeds the critical electric field in all three transit layers. This fact in conjunction with a high-frequency double-mushroom cross-section of the waveguide TTR-PD ensures high output power levels at mmW frequencies. Fabricated 1.55 µm InGaAs(P)/InP waveguide TTR-PDs exhibit output power levels exceeding 0 dBm (1 mW) and a return loss (RL) up to ~24 dB. Broadband operation with a 3 dB bandwidth beyond 110 GHz is achieved.
我们报道了一种用于1.55μm波导光电二极管（PD）的新型三重渡越区（TTR）层结构，该结构在毫米波（mmW）频段可提供高输出功率。基本上，TTR-PD层结构由三个渡越层组成，电子在其中以饱和速度甚至过冲速度漂移。即使在未耗尽的吸收层中，甚至在非常高的光输入功率水平下，所有三个渡越层中都能实现足够强的电场（>3000V/cm）。这是通过并入三个10nm厚的p掺杂电场钳位层来实现的。使用漂移扩散模型（DDM）进行的数值模拟表明，对于高达500kW/cm²的光强，不会出现饱和效应，即所有三个渡越层中的电场都超过临界电场。这一事实与波导TTR-PD的高频双蘑菇横截面相结合，确保了在毫米波频率下的高输出功率水平。制造的1.55μm InGaAs(P)/InP波导TTR-PD的输出功率水平超过0dBm（1mW），回波损耗（RL）高达24dB。实现了超过110GHz的3dB带宽的宽带运行。
