A method for passively coupling an optical fiber to an optoelectronic chip, the method may include connecting the optical fiber to an optical cable interface of a first portion of an optical coupler; wherein the optical coupler further comprises a second portion; wherein the first portion comprises first optics that comprises a first lens array, an optical cable interface and three contact elements, each contact element has a spherical surface; and wherein the second portion comprises second optics that comprise a second lens array, and three elongated grooves; connecting the optical coupler to a substrate that supports the optoelectronic chip; and mechanically coupling the first portion to the second portion by aligning the three contact elements of the first portion with the three elongated grooves of the second portion thereby an optical axis related to a first lens array of the first portion passes through a point of intersection between longitudinal axes of the three elongated grooves, and an optical axis related to the second lens array passes through the point of intersection.