Optical interconnection using cascaded vertical to surface transmission electrophotonic devices

Abstract

The vertical to surface transmission electrophotonic (VSTEP) device, which consists, for example, of pnpn structure,1 has multiple functions such as light emission, light absorption, thresholding, and latching. This multifunctional feature makes it easy to construct a cascaded interconnection, compared with the use of a spatial light modulator, because sources and optics for readout are not necessary. To achieve a stable operation, differential VSTEP devices, which consist of two VSTEPs connected in parallel through a common load resistance, are used. Cascaded interconnection characteristics were measured by using a surface-emitting laser mode VSTEP with vertical cavity.2 A 150-fJ and a 1.7-pJ switching energy have been achieved at 1- and 10-MHz clock frequency, respectively.3 The drive clock signal frequency is >10 MHz, which includes reset, precharge (light absorption), and set times. This frequency may be improved by optimizing the device structure.