We propose a systematic approach to constructing microscopic models with fractional excitations in three-dimensional (3D) space. Building blocks are quantum wires described by the (1+1)dimensional conformal field theory (CFT) associated with a current algebra g. The wires are coupled with each other to form a 3D network through the current-current interactions of g1 and g2 CFTs that are related to the g CFT by a nontrivial conformal embedding g ⊃ g1 × g2. The resulting model can be viewed as a layer construction of a 3D topologically ordered state, in which the conformal embedding in each wire implements the anyon condensation between adjacent layers. Local operators acting on the ground state create point-like or loop-like deconfined excitations depending on the branching rule. We demonstrate our construction for a simple solvable model based on the conformal embedding SU (2)1 × SU (2)1 ⊃ U (1)4 × U (1)4. We show that the model possesses extensively degenerate ground states on a torus with deconfined quasiparticles, and that appropriate local perturbations lift the degeneracy and yield a 3D Z2 gauge theory with a fermionic Z2 charge.Introduction.-Two-dimensional (2D) topologically ordered phases, such as fractional quantum Hall states [1,2] and the toric codes [3], harbor deconfined quasiparticle excitations obeying nontrivial braiding statistics [4]. In three-dimensional (3D) space, topologically ordered phases can have two types of deconfined quasiparticles: point-like or loop-like. While the statistics between point-like quasiparticles can only be bosonic or fermionic in 3D space, there are possibilities of nontrivial pointloop, loop-loop, three-loop, and loop-loop-point braiding statistics [5][6][7][8][9][10][11]. Along with the development of mathematical frameworks for classifying topologically ordered phases [12][13][14][15][16], construction of microscopic Hamiltonians is also desired for their realizations in the real world. For certain 2D topological orders, a systematic construction scheme of exactly solvable Hamiltonians has been proposed by Levin and Wen in their string-net models [17]. Although our understanding of the 3D topological orders is much more limited, there have been several proposed schemes to write down exactly solvable Hamiltonians such as the Dijkgraaf-Witten model [18,19], the Walker-Wang model [20][21][22], and their relatives [23].In this Rapid Communication, we propose yet another way to construct microscopic Hamiltonians for 3D topologically ordered phases. Our approach is based on two key ingredients. The first one is coupled-wire construction of 2D topological phases originally developed by Kane and co-workers [24,25]. This construction uses a hybrid of continuum and lattice descriptions: One spatial direction is a discrete lattice, while the other direction is continuum and described by (1 + 1)-dimensional conformal field theory (CFT) [26]. It has been successfully applied to various 2D topological phases [27][28][29][30][31][32][33][34][35][36][37], and there have been sever...