  Topological edge modes, which are robust against disorders, have been used to
enhance the spatial stability of lasers. Recently, it was revealed that
topological lasers can be further stabilized using a novel topological phase in
non-Hermitian photonic topological insulators. Here we propose a procedure to
realize topologically protected modes extended over a d-dimensional bulk by
introducing an imaginary gauge field. This generalizes the idea of zero-energy
extended modes in the one-dimensional Su-Schrieffer-Heeger lattice into higher
dimensional lattices allowing a d-dimensional bulky mode that is topologically
protected. Furthermore, we numerically demonstrate that the topological bulk
lasing mode can achieve high temporal stability superior to topological edge
mode lasers. In the exemplified topological extended mode in the kagome
lattice, we show that large regions of stability exist in its parameter space.
