391 research outputs found
AlGaAs-On-Insulator Nonlinear Photonics
The combination of nonlinear and integrated photonics has recently seen a
surge with Kerr frequency comb generation in micro-resonators as the most
significant achievement. Efficient nonlinear photonic chips have myriad
applications including high speed optical signal processing, on-chip
multi-wavelength lasers, metrology, molecular spectroscopy, and quantum
information science. Aluminium gallium arsenide (AlGaAs) exhibits very high
material nonlinearity and low nonlinear loss when operated below half its
bandgap energy. However, difficulties in device processing and low device
effective nonlinearity made Kerr frequency comb generation elusive. Here, we
demonstrate AlGaAs-on-insulator as a nonlinear platform at telecom wavelengths.
Using newly developed fabrication processes, we show high-quality-factor
(Q>100,000) micro-resonators with integrated bus waveguides in a planar circuit
where optical parametric oscillation is achieved with a record low threshold
power of 3 mW and a frequency comb spanning 350 nm is obtained. Our
demonstration shows the huge potential of the AlGaAs-on-insulator platform in
integrated nonlinear photonics.Comment: 21 pages, 12 figures, 1 table, 41 reference
Comparison of processing-induced deformations of InP bonded to Si determined by e-beam metrology: direct vs. adhesive bonding
In this paper, we employ an electron beam writer as metrology tool to
investigate distortion of an exposed pattern of alignment marks in
heterogeneously bonded InP on silicon. After experimental study of three
different bonding and processing configurations which represent typical on-chip
photonic device fabrication conditions, the smallest degree of
linearly-corrected distortion errors is obtained for the directly bonded wafer,
with the alignment marks both formed and measured on the same InP layer side
after bonding (equivalent to single-sided processing of the bonded layer).
Under these conditions, multilayer exposure alignment accuracy is limited by
the InP layer deformation after the initial pattern exposure mainly due to the
mechanical wafer clamping in the e-beam cassette. Bonding-induced InP layer
deformations dominate in cases of direct and BCB bonding when the alignment
marks are formed on one InP wafer side, and measured after bonding and
substrate removal from another (equivalent to double-sided processing of the
bonded layer). The findings of this paper provide valuable insight into the
origin of the multilayer exposure misalignment errors for the bonded III-V on
Si wafers, and identify important measures that need to be taken to optimize
the fabrication procedures for demonstration of efficient and high-performance
on-chip photonic integrated devices.Comment: 7 pages, 6 figure
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