Polymeric tunable optical attenuator for power regulator in WDM system

In this paper, we have fabricated a tunable optical attenuator (TOA) based on thermo-optical cutoff modulators in polymers. For the cutoff modulator, a tapered waveguide was employed to reduce the electrical power consumption. It is combined with a fiber coupler which is embedded in a silicon V-groove block to provide two output ports, one main port and one monitoring port. The main port transmits the attenuated output, while the monitoring port has a fraction of the main port power and is used to perform feedback control in order to achieve a constant output when input light power and polarization are varied.