NON-POLARIZATION LIGHT SOURCE DEVICE

摘要

PURPOSE:To enable stable modulation by providing the device with a polarizer arranged between the output end of a laser and the input end of a polarization modulator. CONSTITUTION:A distribution feedback type laser diode 11 is connected to a polarizer 12 by a polarization maintaining optical fiber 15 and the polarizer 12 is connected by a polarization maintaining optical fiber 16 to the polarization modulator 13. The polarization modulator 13 is connected by an optical fiber to the output end 14. The light source device having such constitution has a characteristic that the polarization state of the output light is randomized when a modulation signal of 2Vpi, is impressed thereto. Namely, the light source device has the laser diode 11 which outputs the polarized wave having the specified polarization state, the polarizer 12 which is connected thereto and the polarization modulator 13 which is connected thereto. The polarized wave outputted from the laser diode 11 is converted via the polarizer 12 to the linearly polarized light of a high extinction ratio and is made incident on the modulator 13 subjected to optimum position adjustment and rotation adjustment by the polarizer 12. Then, the stable operation is obtd. without using a polarization controller.