2 research outputs found
Ultra high-Q WGM microspheres from ZBLAN for the mid-IR band
The advantages of high-quality-factor whispering gallery mode microresonators
can be applied to develop novel photonic devices for the mid-IR range. ZBLAN
(glass based on heavy metal fluorides) is one of the most promising materials
to be used for this purpose due to low optical losses in the mid-IR. We
developed original fabrication method based on melting of commercially
available ZBLAN-based optical fiber to produce high-Q ZBLAN microspheres with
the diameters of 250 to 350 m. We effectively excited whispering gallery
modes in these microspheres and demonstrated high quality factor both at 1.55
m and 2.64 m. Intrinsic quality factor at telecom wavelength was
shown which is defined by the material losses in ZBLAN.
In the mid-IR at 2.64 m we demonstrated record quality factor in ZBLAN
exceeding which is comparable to the highest values of the Q-factor
among all materials in the mid-IR
Optimization of laser stabilization via self-injection locking to a whispering-gallery-mode microresonator: experimental study
Self-injection locking of a diode laser to a high-quality-factor
microresonator is widely used for frequency stabilization and linewidth
narrowing. We constructed several microresonator-based laser sources with
measured instantaneous linewidths of 1 Hz and used them for investigation and
implementation of the self-injection locking effect. We studied analytically
and experimentally the dependence of the stabilization coefficient on tunable
parameters such as locking phase and coupling rate. It was shown that precise
control of the locking phase allows fine tuning of the generated frequency from
the stabilized laser diode. We also showed that it is possible for such laser
sources to realize fast continuous and linear frequency modulation by injection
current tuning inside the self-injection locking regime. We conceptually
demonstrate coherent frequency-modulated continuous wave LIDAR over a distance
of 10 km using such a microresonator-stabilized laser diode in the
frequency-chirping regime and measure velocities as low as sub-micrometer per
second in the unmodulated case. These results could be of interest for
cutting-edge technology applications such as space debris monitoring and
long-range object classification, high resolution spectroscopy and others