  We propose an on-chip CMOS compatible graphene plasmonic photodetector based
on the photo-thermoelectric effect (PTE) that occurs across an entire
homogeneous graphene channel. The proposed photodetector incorporates the
long-range dielectric-loaded surface plasmon polariton (LR-DLSPP) waveguide
with a metal stripe serving simultaneously as a plasmon supporting metallic
material and one of the metal electrodes. Large in-plane component of the
transverse magnetic (TM) plasmonic mode can couple efficiently to the graphene
causing large temperature increases across an entire graphene channel with a
maximum located at the metal stripe edge. As a result, the electronic
temperatures exceeding 12000K at input power of only a few tens of {\mu}W can
be obtained at the telecom wavelength of 1550nm. Even with limitations such as
the melting temperature of graphene (T= 4510 K), a responsivity exceeding at
least 200 A/W is achievable at telecom wavelength of 1550 nm. It is also shown
that under certain operation conditions, the PTE channel photocurrent can be
isolated from photovoltaic and p-n junction PTE contributions providing an
efficient way for optimizing the overall photodetector performance.
