  Interactions between solid-state quantum emitters and cavities are important
for a broad range of applications in quantum communication, linear optical
quantum computing, nonlinear photonics, and photonic quantum simulation. These
applications often require combining many devices on a single chip with
identical emission wavelengths in order to generate two-photon interference,
the primary mechanism for achieving effective photon-photon interactions. Such
integration remains extremely challenging due to inhomogeneous broadening and
fabrication errors that randomize the resonant frequencies of both the emitters
and cavities. In this letter we demonstrate two-photon interference from
independent cavity-coupled emitters on the same chip, providing a potential
solution to this long-standing problem. We overcome spectral mismatch between
different cavities due to fabrication errors by depositing and locally
evaporating a thin layer of condensed nitrogen. We integrate optical heaters to
tune individual dots within each cavity to the same resonance with better than
3 {\mu}eV of precision. Combining these tuning methods, we demonstrate
two-photon interference between two devices spaced by less than 15 {\mu}m on
the same chip with a post-selected visibility of 33%. These results pave the
way to integrate multiple quantum light sources on the same chip to develop
quantum photonic devices.
