  We show that strongly correlated photon transport can be observed in
waveguides containing optically dense ensembles of emitters. Remarkably, this
occurs even for weak coupling efficiencies. Specifically, we compute the photon
transport properties through a chirally coupled system of $N$ two-level systems
driven by a weak coherent field, where each emitter can also scatter photons
out of the waveguide. The photon correlations arise due to an interplay of
nonlinearity and coupling to a loss reservoir, which creates a strong effective
interaction between transmitted photons. The highly correlated photon states
are less susceptible to losses than uncorrelated photons and have a power-law
decay with $N$. This is described using a simple universal asymptotic solution
governed by a single scaling parameter which describes photon bunching and
power transmission. We show numerically that, for randomly placed emitters,
these results hold even in systems without chirality. The effect can be
observed in existing tapered fiber setups with trapped atoms.

Quantum Physics;Optics