  Direct exoplanet spectroscopy aims to measure the spectrum of an exoplanet
while simultaneously minimizing the light collected from its host star.
Isolating the planet light from the starlight improves the signal-to-noise
ratio (S/N) per spectral channel when noise due to the star dominates, which
may enable new studies of the exoplanet atmosphere with unprecedented detail at
high spectral resolution (>30,000). However, the optimal instrument design
depends on the flux level from the planet and star compared to the noise due to
other sources, such as detector noise and thermal background. Here we present
the design, fabrication, and laboratory demonstration of specially-designed
optics to improve the S/N in two potential regimes in direct exoplanet
spectroscopy with adaptive optics instruments. The first is a pair of
beam-shaping lenses that increase the planet signal by improving the coupling
efficiency into a single-mode fiber at the known position of the planet. The
second is a grayscale apodizer that reduces the diffracted starlight for
planets at small angular separations from their host star. The former
especially increases S/N when dominated by detector noise or thermal
background, while the latter helps reduce stellar noise. We show good agreement
between the theoretical and experimental point spread functions in each case
and predict the exposure time reduction ($\sim 33\%$) that each set of optics
provides in simulated observations of 51 Eridani b using the Keck Planet Imager
and Characterizer instrument at W.M. Keck Observatory.
