KANATA, Ontario, Canada, May 30 -- GSI Lumonics Inc., has received an ิ8.7-million order from a semiconductor manufacturer to provide laser systems to process semiconductor circuits used in computer and communications applications.   This order reflects the continuing strength of the linear and mixed signal segment of the semiconductor industry, said Charles D. Winston, president and CEO of GSI. We are very pleased that leading customers continue to recognize the exceptional value that our systems add to their manufacturing processes.   GSI Lumonics produces laser-based manufacturing systems and components to the semiconductor, electronics and automotive industries; the company also supplies precision optics for telecommunications.