  We explore new methods for coupling light to on-chip gallium arsenide
nanophotonic structures using etched conical optical fibers. With a
single-sided conical fiber taper, we demonstrate efficient coupling to an
on-chip photonic bus waveguide in a liquid environment. We then show that it is
possible to replace such on-chip bus waveguide by two joined conical fibers in
order to directly couple light into a target whispering gallery disk resonator.
This latter approach proves compliant with demanding environments, such as a
vibrating pulse tube cryostat operating at low temperature, and it is
demonstrated both in the telecom band and in the near infrared close to 900 nm
of wavelength. The versatility, stability, and high coupling efficiency of this
method are promising for quantum optics and sensing experiments in constrained
environments, where obtaining high signal-to-noise ratio remains a challenge.
