In this paper,we have proposed a hybrid optical wavelength demultiplexer and power combiner for a hybrid timeand wavelength-division multiplexing(TWDM)passive optical network(PON),i.e.,a single passive optical device that functions as a 1×N wavelength demultiplexer for distributing the downstream signal in multiple wavelengths from the optical line terminal(OLT)to the N optical network units(ONUs),and simultaneously as an N×1 power combiner for collecting the upstream signal in the same wavelength from the N ONUs to the OLT.Through a design example of a 32 channel hybrid optical wavelength demultiplexer and power combiner on the silicon-on-insulator platform,our numerical simulation result shows that the insertion loss and adjacent channel crosstalk of the downstream wavelength demultiplexer are as low as 4.6 and-16.3 dB,respectively,while the insertion loss and channel non-uniformity of the upstream power combiner can reach 3.5 and 2.1 dB,respectively.The proposed structure can readily be extended to other material platforms such as the silica-based planar lightwave circuit.Its fabrication process is fully compatible with standard clean-room technologies such as photolithography and etching,without any complicated and/or costly approach involved. In this paper, we have proposed a hybrid optical wavelength demultiplexer and power combiner for a hybrid time and wavelength-division multiplexing (TWDM) passive optical network (PON), ie, a single passive optical device that functions as a 1 × N wavelength demultiplexer for distributing the downstream signal in the optical line terminal (OLT) to the N optical network units (ONUs), and simultaneously as an N × 1 power combiner for collecting the upstream signal in the same wavelength from the N ONUs to the OLT . Thhough a design example of a 32 channel hybrid optical wavelength demultiplexer and power combiner on the silicon-on-insulator platform, our numerical simulation result shows that the insertion loss and adjacent channel crosstalk of the downstream wavelength demultiplexer are as low as 4.6 and- 16.3 dB, respectively, while the insertion loss and channel non-uniformity of the upstream power combiner can reach 3.5 and 2.1 dB, respectively. The proposed structure can read ily be extended to other material platforms such as the silica-based planar lightwave circuit. Its fabrication process is fully compatible with standard clean-room technologies such as photolithography and etching, without any complicated and / or costly approach involved.