Minneapolis-based ADC Telecommunications Inc. announced plans to acquire Altitun AB of Kista, Sweden, a manufacturer of tunable lasers for optical telecommunications. Under terms of the proposed transaction, ADC would issue shares of its common stock to holders of Altitun in a swap valued at more than $870 million. The company also announced the purchase of Ibsen Micro Structures A/S of Farum, Denmark. The $80 million purchase would give it Ibsen's experience in the development and production of phase masks, fiber Bragg gratings and integrated photonic systems.