Thanks, FJ and Shash!  Very helpful.  Your first grade student has just now begun Grade 2, despite the protestations of the parents of other promoted 2nd grade students!  From FJ's link:

"The POET Optical Engine consists of the POET Optical Interposer, lasers, photo detectors, laser monitor, waveguides, and filters integrated within the waveguides for multiplexing and de-multiplexing signals."

So now I know the OI is a really small chip, 500 of them on an 8" wafer.  Now in comparison, how big is the Optical Engine once the above items are integrated with the OI? And Poet is manufacturing and selling the engine or just the OI?