This white paper describes the design of a DSP-based control system for erbium-doped fiber amplifiers in order to stabilize the wavelength of multiple pump lasers. The platform shows a single TMS320F2812 DSP (abbreviated “F2812” throughout this document) controlling the temperature of four lasers. The analog portions of the design were chosen to minimize the temperature measurement error and maximize the efficiency of the drive to the thermoelectric cooler. The platform highlights the advantages of using a single DSP in this application over using discrete TEC controller modules:
• the ability to control the edges of the PWM signals to the TEC drivers, minimizing electrical noise;
• the ability to use the programmability of the DSP to easily handle exception processing;
• the extendibility of the design to additional TEC channels;
• the ability to add function easily to the DSP to control other aspects of the design, such as back facet diode monitoring and dynamic gain flattening filtering.
The paper concludes showing methods to add additional channels to the base design and reduce the board space of the design.