Quantum Maxwell-Bloch equations for spontaneous emission in optical   semiconductor devices
  We present quantum Maxwell-Bloch equations (QMBE) for spatially inhomogeneous optical semiconductor devices taking into account the quantum noise effects which cause spontaneous emission and amplified spontaneous emission. Analytical expressions derived from the QMBE are presented for the spontaneous emission factor beta and the far field pattern of amplified spontaneous emission in broad area quantum well lasers. 
Ortwin Hess and Holger F. Hofmann