Variable wavelength filter, and light receiver and light receiving method using variable wavelength filter

A wavelength tunable filter, a transmission wavelength of which is tuned based on heat, comprising:

• a filter configured to pass through a preset wavelength;
• and
• a heater formed on a portion of an upper surface of the filter,
• wherein light passes through a portion on which the filter is not formed.

An optical receiver, comprising:

• a photodiode;
• at least one capacitor;
• and
• a lens positioned above the photodiode,
• wherein the at least one capacitor is positioned in vicinity of the photodiode.

An optical receiver, comprising:

• a photodiode;
• a thermo-electric element positioned not to overlap the photodiode;
• a lens positioned above the photodiode;
• and
• a wavelength tunable filter positioned above the lens, configured to transmit light of a preset wavelength,
• wherein a portion of the wavelength tunable filter is coupled to the thermos-electric element,
• wherein another portion of the wavelength tunable filter except for the portion of the wavelength tunable filter is positioned above the lens, so that in the top view of the optical receiver, the lens is covered by the another portion of the wavelength tunable filter, and
• wherein the preset wavelength of the wavelength tunable filter is tuned according to a temperature of the thermos-electric element.