4-CHANNEL INTEGRATED DFB LASER ARRAY WITH TUNABLE WAVELENGTH SPACING AND 40-GB S SIGNAL TRANSMISSION CAPACITY/

A four-channel DFB laser array integrated with four heating filaments are fabricated for high density wavelength division multiplexing syste ms. The DFB lasers have a threshold current of 4 mA at room temperatur e. By changing the power in the heater, the wavelength of each laser c an be continuously tuned by as much as 5 nm. Therefore, a tunable wave length spacing anywhere from 1 nm to 2 nm can be achieved. Each laser can operate at 10 Gb/s. However, the bias current has to be increased to avoid the degradation of the eye pattern as the wavelength is therm ally tuned over 2 nm. An electric crosstalk of 0.6 dB is measured whil e two adjacent lasers are modulated at 10 Gb/s simultaneously.