An optical subassembly comprising: an interposer having first and second opposing sides and defining an alignment aperture extending from said first opposing side to said second opposing side , said interposer defining traces having first, second, and third contacts , said first contacts being configured for electrical connection to at least one optical component , said second contacts being configured for electrical connection to at least one chip , and said third contacts being configured for electrical connection to a circuit board; at least one fiber disposed at least partially in said alignment aperture and having a first optical axis , said fiber being held such that said first optical axis is positioned essentially orthogonal to said first and second opposing sides; said at least one optical component mounted to said second opposing side and being electrically connected to at least a portion of said first contacts , said at least one optical component having a second optical axis coincident with said first optical axis ; said at least one chip for operating said at least one optical component , said at least one chip being mounted on said first or second opposing side and electrically connected to at least a portion of said second contacts ; and said circuit board configured to receive said interposer such that said interposer is essentially orthogonal to said circuit board, said circuit board being electrically connected to at least a portion of said third contacts , said fiber being a fiber stub ; characterized in that : (i) said interposer is rigid and planar; (ii) said fiber stub is polished to be flush with said first and second opposing sides. an interposer having first and second opposing sides and defining an alignment aperture extending from said first opposing side to said second opposing side , said interposer defining traces having first, second, and third contacts , said first contacts being configured for electrical connection to at least one optical component , said second contacts being configured for electrical connection to at least one chip , and said third contacts being configured for electrical connection to a circuit board; at least one fiber disposed at least partially in said alignment aperture and having a first optical axis , said fiber being held such that said first optical axis is positioned essentially orthogonal to said first and second opposing sides; said at least one optical component mounted to said second opposing side and being electrically connected to at least a portion of said first contacts , said at least one optical component having a second optical axis coincident with said first optical axis ; said at least one chip for operating said at least one optical component , said at least one chip being mounted on said first or second opposing side and electrically connected to at least a portion of said second contacts ; and said circuit board configured to receive said interposer such that said interposer is essentially orthogonal to said circuit board, said circuit board being electrically connected to at least a portion of said third contacts , said fiber being a fiber stub ; characterized in that : (i) said interposer is rigid and planar; (ii) said fiber stub is polished to be flush with said first and second opposing sides. (i) said interposer is rigid and planar; (ii) said fiber stub is polished to be flush with said first and second opposing sides. <EOS>