Frequency stabilization by dithering bias current of laser diodes for carrier-distributed WDM-based access networks

Abstract

We indicate that the frequency drift of WDM light sources for uplink transmission in carrier-distributed WDM-based access networks severely impacts the loss budget. To prevent this, we propose a multifrequency monitoring-stabilization technique that simplifies the configuration of WDM light sources. To achieve more precise frequency stabilization the bias current used to drive each laser diode is dithered. The key techniques are adding an offset bias to the detected error signal and offsetting the center frequency of the array waveguide grating port against the ITU-T grid frequency to achieve effective frequency stabilization. Experiments show that the relative frequency deviation of +/-25 GHz can be suppressed to better than +/-2.5 GHz.