Multiwavelength monitoring by dithering temperature of directly-modulated laser diodes

A multiwavelength monitoring technique for wavelength division multiplexed passive optical network systems is proposed. This technique removes the need to place one optical filter at each transmitter and so makes their configuration more compact. To generate a wavelength monitoring signal, the temperature of each directly-modulated laser diode is dithered by a sinusoidal signal. Experiments confirm the feasibility of this technique.