Patent ID: 7127139

Claim:
An optical multiplexer, in which a first light being propagated through an optical fiber is multiplexed with a second light having a wavelength different from that of said first light, comprising: a first fiber Bragg grating, which has transmission wavelength characteristics to transmit said first light and to reflect said second light, and is formed on said optical fiber with a grating direction thereof being tilted to an axial direction of said optical fiber; a light source irradiating lights containing a wavelength component of said second light to said first fiber Bragg grating from an angle direction determined according to a grating pitch of said first fiber Bragg grating and the wavelength of said second light; and a second fiber Bragg grating, which has the reflectance lower than the reflectance of said first fiber Bragg grating relative to said second light and has a grating plane perpendicular to the axial direction of said optical fiber, and is formed on said optical fiber on the side where said second light irradiated from said light source to said first fiber Bragg grating and coupled within said optical fiber is propagated, wherein said second light is resonated between said light source and said second fiber Bragg grating via said first fiber Bragg grating; and wherein said light source irradiates a light obtained by polarizingly combining a plurality of lights in different polarization states to said first fiber Bragg grating.