To demonstrate optical communication through stacked silicon circuitry, thin film InGaAsP-based emitters and photodetectors have been bonded directly onto silicon circuitry. These optoelectronic devices operate at a wavelength to which silicon is transparent. The thin film emitters and detectors were integrated onto a MOSIS foundry silicon CMOS integrated circuit which contained driver and amplifier circuits. Bidirectional vertical optical communication between two layers of circuitry was demonstrated by stacking the layers, exciting the emitter driver circuit on one layer with an electrical signal, and measuring the output electrical signal from the detector amplifier located on the other circuit in the vertical stack.