  Power amplifier is becoming a critical component for integrated photonics as
the integrated devices try to carve out a niche in the world of real-world
applications of photonics. That is because the signal generated from an
integrated device severely lacks in power which is due mainly to the small size
which, although gives size and weight advantage, limits the energy storage
capacity of an integrated device due to the small volume, causing it to rely on
its bench-top counterpart for signal amplification downstream. Therefore, an
integrated high-power signal booster can play a major role by replacing these
large solid-state and fiber-based benchtop systems. For decades, large mode
area (LMA) technology has played a disruptive role by increasing the signal
power and energy by orders of magnitude in the fiber-based lasers and
amplifiers. Thanks to the capability of LMA fiber to support significantly
larger optical modes the energy storage and handling capability has
significantly increased. Such an LMA device on an integrated platform can play
an important role for high power applications. In this work, we demonstrate LMA
waveguide based CMOS compatible watt-class power amplifier with an on-chip
output power reaching ~ 1W within a footprint of ~4mm2.The power achieved is
comparable and even surpasses many fiber-based amplifiers. We believe this work
opens up opportunities for integrated photonics to find real world application
on-par with its benchtop counterpart.
