LIGENTEC offers its proprietary silicon nitride (Si3N4) platform based on the Photonic Damascene Process (patent pending), targeted at applications using integrated photonic chips from visible to mid-IR.
Silicon nitride as a material strikes a balance between silicon and silicon oxide. Silicon nitride has:
- ultra wide transparency window reaching from 250-8000nm of wavelength
- high refractive index of 2.00 enabling high confinement waveguides and cost benefits through reduced device size
- deposited amorphous material allowing monolithic 3D integration of devices on the same chip
- high nonlinear coefficient for nonlinear integrated photonics applications
|Property||Silicon||Silicon nitride||Silicon oxide|
|Transparency window||1.1-9 μm||0.25-8 μm||0.13-3.5 μm|
|Band gap||1.12 eV||5 eV||9 eV|
|Refractive index @ 1550 nm||3.8||2.00||1.46|
|Nonlinear coefficient (m2W-1)||~ 6*10-18||2*10-19||~ 2.5*10-20|
|Deposition||Crystal material EPI/SOI*||High quality deposited by LPCVD||Thermally grown*|
*film in direct contact to substrate
The waveguides are built by high quality silicon nitride, cladded in high quality silicon dioxide. Nitride thickness is fixed per batch and ranging from 600-1300nm depending on the application. Such high nitride thickness is enabled by LIGENTEC Photonic Damascene Process, ensuring exceptional mode confinement, sharp bending radius and reduced device footprint. The high nitride thickness permits anomalous dispersion and a high damage threshold that is very important for nonlinear optical applications of these integrated devices.
LIGENTEC Photonic Damascene Process offers a state of the art, cost-effective platform with superior critical dimension and thickness control. The process is accompanied by a validated design library, offering a rapid and low cost prototyping solution. The library developed with VLC Photonics includes integrated components for:
- spot converters
- ultra low loss spirals
- MZI, MMI
- ring resonators
To lower the entry cost to LIGENTEC processes a multi-project wafer run is available were the users share the process and engineering cost. For different target applications from the visible to mid-infrared we offer different waveguide thickness shown in the table below.