Sula the POET GaAs platform roadmap included in-plane applications which would be compatible with single mode lasing at the edge which could utilize BB Phonics waveguide technology. Below is extracted from the POET Digital Opto-Electronic Switch white paper. Thyristor operation for in-plane geometry may provide for another opportunity to access the fourth terminal.  

Specifically compared to SiP, in-plane lasing with POET technology provides access to critical active components – primarily the laser and the semiconductor Optical Amplifier. Additional advantages of the POET solution to more conventional in-plane lasing solutions are :

- tight confinement of light in the waveguides enabling 90 degree bends and smaller features

 - strong index change through carrier modulation in the quantum wells

- no epitaxial growth interface to the waveguide resulting in low loss light coupling

 - automatic locking of wavelength due to resonant cavities eliminating the need for wavelength tuning and heater elements