Technology
The invention introduces a method for fabricating ferroelectric crystal
lines for use as low loss optical waveguides with additional active
functionality compared to amorphous/glass waveguides.
It provides low losses by confining the light signal tightly in the
crystal core, away from the rough crystal-glass
interface that is often responsible for losses in such a system. These
new types of waveguides consisting of active crystals, such as lithium
niobate, in glass, can be fabricated in complex architecture, suitable
for realizing integrated optical elements within the glass substrate at
low cost. GRISC waveguides have much lower losses than other
competing options.
The GRISC in glass is created through
control of the temperature distribution induced by femtosecond laser
heating. Within the glass, the femtosecond laser induced temperature
profile allows for crystallization upon heating, ahead of the laser focus.
The refractive index contrast generated using this method leads to tight
optical confinement of the transmitted light in a Gaussian profile. Such
a profile results in most of intensity in the center where losses are low,
and very low intensity near the crystal-glass interface where losses tend
to be high.
Competitive Advantage
Glass cannot fundamentally possess some of the active capabilities of
optical crystals like lithium niobate, which are required in optical communication,
such as high electro-optic coefficient and second order optical nonlinearity.
This invention allows for such
optical crystals to be integrated as low loss optical waveguides with
active properties that additional functionalities than those of amorphous/glass
waveguides. Other advantages conferred by this invention include the
ability to fabricate GRISC in glass and ensure radially symmetric crystal
misorientation of the crystal line. The growth mode proposed eliminates
the problem of non-uniform polycrystallinity. Misorientation also helps
decrease the refractive index of the crystal line and helps in producing
optically active GRISC waveguide within glass.
Market Need/Opportunity
This invention would be useful in different market segments
associated with photonics and optical equipment. The demand for silicon
photonics technology has increased owing to their various functionalities
and day-to-day use in data communication and telecommunication
applications for high bandwidth data transmission in small and large
networks. GRISC can be used as a low loss optical waveguide to
improve integrated optic devices such as electro-optic modulators. With
rare earth doping, GRISC can be used in optical quantum memory
applications.
Status
Lehigh University is looking for a partner for further development and
commercialization of this technology through a license. The inventor is
available to collaborate with interested companies.
Tech - ID
111116-01
Inventors
Keith Veenhuizen
Volkmar Dierolf
Himanshu Jain, PhD