Lightwave Logic Inc (LWLG)

[spartex]

jeunke, do you have a link to that Optica video from a few weeks back?

I just did a quick search on PIC's publication papers and found this one from Jan 2024 in Nature. Looks interesting, and may have been posted on this board some months ago. Thx!

Roadmapping the next generation of silicon photonics

https://www.nature.com/articles/s41467-024-44750-0

Did word search on polymers and they wrote this up:

Polymer silicon-organic-hybrid (SOH)67,72 and plasmonic-organic-hybrid (POH)69 require poling and hermetic sealing, creating significant challenges to making stable devices. Their high-temperature reliability and reflow compatibility need to be further demonstrated, although recent results are promising72. POH modulators, even though they look attractive in the PPA metrics, further suffer from compatibility with CMOS SOI foundries. Good plasmonic metals (Cu, Ag, Au) are also serious contaminants, and need diffusion barrier layers (e.g., TaN) which are optically very lossy.

Polycrystalline layers of other ferroelectric thin-film materials such as BTO show much larger Pockels coefficient (expressed in pm/V) than LNOI73 and comparable to polymers74, and recent demonstrations of large E/O BW65,75 make them promising. Note that a large Pockels coefficient in the device is important, which requires a good overlap of the electric modulation field and the propagating optical mode49,72. As part of the direct wafer bonding process, BTO thin films are fabricated first using molecular beam epitaxy deposition on donor wafers, and then directly wafer bonded to interlayer dielectric/SiO2 of the planarized acceptor SOI wafer using intermediate alumina layers as an adhesive. BTO also requires poling to compensate for hysteresis from ferroelectric domain switching (albeit only?~?1V DC compared to much larger voltages needed for polymer modulators)65. Sources of propagation loss include scattering from waveguide sidewall roughness and residual oxygen vacancies in the BTO thin film—areas for further improvement. BTO also has a lower refractive index compared to Si (nBTO = 2.38, nSi = 3.47 @ 1550 nm) and a significantly large RF relative permittivity that can increase capacitances and velocity mismatch between the optical and electrical fields.

Improving all PPA metrics and HVM suitability is crucial for commercial foundries and LSI applications. However, thanks to the numerous photonic applications, there will always be a need for exceedingly high E/O BW modulators, and several prototyping and R&D foundries will continue to address the related fabrication challenges. Finally, although >100 GHz E/O BW modulators are attractive for both telecom and data center applications, they require electronics capable of driving them at such speeds. Unless Vp (or Vpp) is reduced significantly, such electronics will consume a lot of power, regardless of CMOS/BiCMOS/III-V implementation.

Hmmmm, I believe Lightwave has solved that Vp issue for the most part, huh? 😄