The Unidirectional Integrated Tap Photodiode (UTPD) integrates the functionality of an optical coupler and a photodiode for optical network's power detection. The unidirectional feature allows the PD to respond to power from input port only. It can be applied for channel power monitoring in DWDM system, in-line optical network switching protection monitoring (OLP), reconfigurable optical add/drop multiplexers (ROADM), and gain/attenuation monitoring in EDFAs, network's power detection, etc.
