An article comprising an optical waveguide (400, 800), wherein the optical waveguide (400, 800) comprises: (a) a lower cladding (102, 822), (b) a composite light-guiding region, disposed above said lower cladding (102, 822), and exhibiting a balanced stress configuration, said composite light-guiding region consisting of at least three conformal layers (407, 409, 411, 807, 809, 811) wherein: two (407,411, 807, 811) of said three conformal layers (407, 409, 411, 807, 809, 811) exhibit residual stress of the same sign; and are separated by one or more interposed layers (409, 809); said one or more interposed layers (409, 809) exhibit residual stress of opposite sign relative to said two layers (407, 411, 807, 811); and said interposed layers (409, 809) are suitable for guiding light based on the relative refractive indices of said interposed layers (409, 809) and said two layers (407, 411, 807, 811); wherein the material of said two layers (407, 411, 807, 811) is stoichiometric silicon nitride or silicon-rich silicon nitride; (c) an upper cladding, wherein at least a portion of said upper cladding is disposed above said composite light-guiding region, wherein the thickness of one or more of the three conformal layers (407, 409, 411, 807, 809, 811) is adjusted in order to achieve a balanced stress configuration in the composite light-guiding region and a reduced modal birefringence in the optical waveguide (400, 800). (a) a lower cladding (102, 822), (b) a composite light-guiding region, disposed above said lower cladding (102, 822), and exhibiting a balanced stress configuration, said composite light-guiding region consisting of at least three conformal layers (407, 409, 411, 807, 809, 811) wherein: two (407,411, 807, 811) of said three conformal layers (407, 409, 411, 807, 809, 811) exhibit residual stress of the same sign; and are separated by one or more interposed layers (409, 809); said one or more interposed layers (409, 809) exhibit residual stress of opposite sign relative to said two layers (407, 411, 807, 811); and said interposed layers (409, 809) are suitable for guiding light based on the relative refractive indices of said interposed layers (409, 809) and said two layers (407, 411, 807, 811); wherein the material of said two layers (407, 411, 807, 811) is stoichiometric silicon nitride or silicon-rich silicon nitride; two (407,411, 807, 811) of said three conformal layers (407, 409, 411, 807, 809, 811) exhibit residual stress of the same sign; and are separated by one or more interposed layers (409, 809); said one or more interposed layers (409, 809) exhibit residual stress of opposite sign relative to said two layers (407, 411, 807, 811); and said interposed layers (409, 809) are suitable for guiding light based on the relative refractive indices of said interposed layers (409, 809) and said two layers (407, 411, 807, 811); wherein the material of said two layers (407, 411, 807, 811) is stoichiometric silicon nitride or silicon-rich silicon nitride; (c) an upper cladding, wherein at least a portion of said upper cladding is disposed above said composite light-guiding region, wherein the thickness of one or more of the three conformal layers (407, 409, 411, 807, 809, 811) is adjusted in order to achieve a balanced stress configuration in the composite light-guiding region and a reduced modal birefringence in the optical waveguide (400, 800).