This document covers the performance specification for electroabsorption (EA) type optical modulators monolithically integrated with laser diodes for 40 Gbit/s fibre optic transmission systems. This performance standard contains a definition of the product performance requirements together with a series of sets of tests and measurements with clearly defined conditions, severities and pass/fail criteria. The tests are intended to be run as an initial design verification to prove any product s ability to satisfy the performance standard s requirements. This standard is applicable for on-off keying format. A product that has been shown to meet all the requirements of a performance standard can be declared as compliant with the performance standard but should then be controlled by a quality assurance program.