The American company, Nortel Networks, has bought a Zurich subsidiary of Canada's JDS Uniphase company. The sale, worth SFr4.9 billion ($2.99 billion), was concluded on Tuesday.
The deputy manager of Nortel's Swiss branch, Thomas Marfurt, said there would be no layoffs in Zurich, nor at Nortel's own offices.
Four hundred employees currently work for JDS Uniphase AG, constructing high-precision optical laser pump chips.
The Zurich company is one of two companies worldwide capable of making the laser pumps, which are essential for optical internet infrastructures.
Nortel is a leader in optical, mobile communications and data networks, as well as e-commerce. The company employs 160 people in Switzerland, and has a turnover of SFr160 million.
Worldwide, it employs 90,000 people, and increased its turnover last year by 40 per cent, to $30 billion.
swissinfo with agencies