OPTICAL TRANSMITTING DEVICE

摘要

PROBLEM TO BE SOLVED: To secure many signal beams within a limited band and to attain the communication of large capacity by connecting a constant polarization optical fiber having its length larger than the prescribed value to the following state of an optical amplifier using a constant polarization amplifier fiber to generate a continuous wavelength beam having a stable plane of polarization, taking a beam of a desired wavelength out of the continuous wavelength beam via a constant polarized optical branching filter, and superimposing the desired information on the taken-out beam via an external modulator. SOLUTION: An SC(super continuum) light source 4 consists of an optical amplifier 2 using a constant polarization amplifier fiber 1 and a constant polarization fiber 3 having its length larger than the prescribed value. Then the source 4 keeps a constant plane of polarization until the source light inputted via an input part reaches an output part 12 and generates the light having the spread of wavelength from the source light having no spread of wavelength. The light of desired wavelength is branched out of the light generated by the source 4 by a constant polarization optical branching filter 5 and modulated by an external modulator 6, and the signal beams are transmitted. Thus, many signal beams are secured within a narrow band that is available for the amplifier 2 to perform the communication almost with no variance of wavelength.