Optical device having switching function

An optical device having a switching function, comprising:

• an input waveguide and an output waveguide, said input waveguide and said output waveguide being partially disposed to be adjacent each other, thereby forming a 3 dB coupler,
• a waveguide filter for switching an input signal light including at least one specific wavelength to be transmitted or reflected therein, said waveguide filter including a pair of gratings and phase shift switches provided on extending parts of both said input waveguide and said output waveguide extended from said 3 dB coupler;
• a first circulator connected to said input waveguide and having an input port for inputting said input signal light to said waveguide filter, and a drop port for outputting said reflected signal light of said at least one specific wavelength;
• a second circulator connected to said output waveguide and having an output port for outputting said transmitted signal light, and an add port for inputting an add signal light of said at least one specific wavelength;
• and
• a reflecting film disposed on ends of both said input waveguide and said output waveguide.