Silicon Optical Bench (SiOB) is a popular solution for passive assembly of optical module. In order to realize an optical
transmitter or receiver module, it is necessary to integrate high frequency optoelectronic components such as signal
photodiodes (PD) or laser diodes (LD) onto the SiOB. In this way, the module's electrical and optical performances can
be further improved, and a higher degree of miniaturization can be achieved. The challenge for this integration is not
only on the assembly accuracy for the LD and PD, it required the design of low loss electrical interconnect at high
frequency. However, the standard silicon substrate used in the SiOB has a high electrical loss especially at high
frequency. This imposed a limitation on the electrical interconnection length between the optoelectronic components and
their I/O interfaces. It is proposed here to design the electrical interconnection using a layer of SiO2 sandwiched between
two layers of metal layer. Simulations have demonstrated that by varying the thickness of the SiO2 layer, an optimum
electrical performance can be achieved.
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