Function Description

Laser diodes are being used in numerous industries, for various applications. Optical fibre communications use laser sources with predetermined wavelengths and amplitudes which are then modulated based on an encoded bit stream. The current trend in optical fibre communications is to use tunable laser diodes as sources rather than using fixed wavelength laser diodes due to the cost advantages and replaceability.

In a tunable laser diode, the output wavelength depends on the junction temperature of the diode. The junction temperature depends on the current driven through the laser diode and the action of the cooling mechanism, which is often based on Thermo Electric Cooler control (Peltier cooling). The current driven through the laser diode determines the amplitude of the output waveform and therefore by adjusting the current precisely, the output power of the laser diode can be controlled.

The objective of the project is to design and implement a low-cost laser diode driver while delivering a performance comparable to the commercially available units. It is expected to design a laser diode driver that can operate in the 0 – 200 mA range with a step resolution of 10 µA. As such, the project includes a comparison of different designs applicable, a simulation of the considered solutions, choosing the optimal solution that can deliver the intended outcome and implementation and testing of the design on printed circuit boards.