I took a quick look. Monolithic InP PIC. So very complicated and not your mix and match of the best devices using different material sets from the global supplier pool. 

These monolithic approaches always create compromise in the optimization process. The devices that are efficiently integrated on the POET Optical Interposer are optimized under the best conditions for that material set before being integrated onto the POET platform (known good die). Typically InP waveguide loss is around 1.2dB/cm. The POET optical interposer waveguides achieve low loss of less than .3dB/cm. POET’s waveguides are also largely athermal so there is less thermal control to fix the wavelength. 

As I scanned Effects patents it brought back memories of Dr Taylor’s GaAs work and ultimately the issues around the creation of P contacts. 

So good luck bucking the Silicon Industry. POET of course uses the silicon ecosystem.

This is a very quick look but the arrayed waveguides look really complex and are multiplied up to 6 times for each wavelength with lots of measures to avoid crosstalk. POET of course has the ability to place the transmit and send waveguides on different planes crossing over each other without crosstalk (excellent confinement). 

No sign of mirror fabrication for in-plane/out-of-plane applications.