The present application provides a tunable optical filter, including: a substrate, a tunable filter unit, a temperature control unit, and an enclosure, where: the substrate, the tunable filter unit, and the temperature control unit are placed inside the enclosure, where the enclosure includes a light incidence window and a light emergence window; the substrate is disposed adjacent to the light incidence window or the light emergence window, and configured to support the tunable filter unit; the temperature control unit is disposed on a surface of the tunable filter unit, and configured to adjust a channel wavelength of the tunable filter unit by means of temperature control; and optical paths of the light incidence window, the tunable filter unit and the light emergence window are aligned. The present application further provides an optical receive component, an optical transceiver component, and a multi-wavelength passive optical network system.