A compact 2.5Gbps wavelength-tunable DWDM transmitter with direct-modulated DFB

A 2.5Gbps wavelength-tunable light source has been and will be for several years one of the most important component in a metropolitan core DWDM network. The world's smallest wavelength-tunable transmitter module was successfully developed by using low cost direct-modulated DFB technology and newly designed integrated control circuits. All of the following functions are mass-produced in the 24-pin butterfly package (W18 /spl times/ D35 /spl times/ H8.5mm): a laser diode (LD) chip, a LD driver IC, an optical lens system, a thermo electric cooler (TEC) and a central processing unit (CPU) that controls LD temperature and its bias/modulation currents. The module can pick through its digital control interface and transmit one of four neighboring 100GHz ITU-T channels. The wavelength is tuned at 1GHz step even without a wavelength locker by precisely controlled temperature.