<p>Large-scale integrated sources of quantum light are enabling ingredients for the future of photonic quantum technologies. For such platforms, sources based on electrical injection are of value for their turnkey operation, as they do not rely on bulky off-chip sources to achieve quantum nonlinear conversion. This work presents the first demonstration of a source of entangled photons fully contained in a single waveguide. Our source is based on a single battery-powered Bragg reflection waveguide diode laser producing two indistinguishable sources of ultra-broadband polarization-entangled photons. The output state of our device has a Bell-state fidelity of 86.3% without accidental subtraction, a high entangled pair generation rate of 1.16 × 10⁶ (pairs)/(s ⋅ mW ⋅ facet), and an ultra-broadband entangled photon pair bandwidth &gt;5.22 THz. Our approach yields scalable, compact, low-power, and stable sources of polarization-entangled photons, needed for real-world applications of quantum communications and network systems.</p>