Integrated fiber-optic detector based on dip-coated colloidal quantum dots

In long haul telecommunications optical fibers are perfect waveguides for light. However, the monitoring of the transmitted optical power generally demands the conversion from optical pulses into electrical signals, which relies on discrete photodetectors made by silicon or III-V materials. Here, we report an integrated fiber-optic detector by dip coating PbS colloidal quantum dots onto a pretreated specialty optical fiber. We characterized the readout currents at 1550nm as a function of the optical power, the bias voltage and the distance between the contact electrodes. Ways of improving the responsivity and the potential applications in in-line multi-wavelength optical power measurement are discussed as well.