Abstract: A low-noise optical fiber amplifier for performing a long-distance optical transmission in a wavelength division multiplexing optical transmission apparatus is provided. This amplifier includes a first optical fiber amplifier having a pre-stage optical fiber, and a first coupler for supplying pump light to the pre-stage optical fiber; a dispersion compensating Raman amplifier (DCRA) connected to the first optical fiber amplifier and having a dispersion compensating optical fiber (DCF) that compensates for the dispersion accumulated in an optical line and generates a Raman gain, and a second coupler for supplying Raman pump light onto the DCF; and a second optical fiber amplifier connected to the DCRA, and including a post-stage optical fiber and a third coupler for supplying pump light onto the post-stage optical fiber. Accordingly, this optical fiber amplifier is used for terrestrial WDM optical transmission, and thus has remarkably low noise figure compared to the existing optical amplifiers.

Abstract: A control device for controlling an electro-optic modulator which receives an optical input signal, modulates the optical input signal with an electrical input signal and a bias voltage signal, and outputs the modulated optical signal is provided. The control device includes: a light source for providing the optical input signal used for the optical modulation to the electro-optic modulator; an optical input measuring unit for measuring the intensity of the optical input signal outputted by the light source; an optical output measuring unit for measuring the intensity of the optical output signal outputted by the electro-optic modulator; and a controller for adjusting the bias voltage signal and the gain of the electrical input signal depending on the intensity of the optical input signal and the optical output signal measured respectively by the optical input measuring unit and the optical output measuring unit.

Abstract: Disclosed is a Brillouin erbium-fiber laser system producing multiwavelengths with a dual spacing of 10 GHz and 20 GHz. The Brillouin erbium-fiber laser system includes: a Sagnac reflector generating even- and odd-order Strokes waves by launching input lights, a first unit forming a first resonator with the Sagnac reflector, wherein the first unit is coupled to a first directional coupler in the Sagnac reflector, a second unit forming a second resonator with the Sagnac reflector, wherein the second unit is coupled to the first directional coupler in the Sagnac reflector, and a third unit for inputting Brillouin pump light into one of first and the second units, whereby the optical fiber laser system outputs multiwavelengths with a dual spacing.

Abstract: The invention relates to a hybrid fiber amplifier in which a dispersion compensating Raman amplifier is associated with an erbium doped fiber amplifier to enhance the amplifier efficiency. It is an object of the invention to provide a dispersion compensating Raman amplifier(DCRA) by inducing Raman pump light into a dispersion compensating fiber to obtain a Raman gain in which a depolarizer is used to eliminate the pump light polarization dependent Raman gain, and a hybrid fiber amplifier in which the DCRA is associated with an erbium doped fiber amplifier(EDFA) to enhance the efficiency.

Abstract: A multichannel light source wavelength and strength stabilizing apparatus and a method thereof are disclosed.

Abstract: The present invention discloses an apparatus for suppressing stimulated Brillouin scattering and the method thereof that a threshold fiber input power is raised in order to prevent loss of an inputted light by stimulated Brillouin scattering being generated in a case that a signal having a strong intensity is inputted to the optical fiber and so a light signal having more strong intensity can be inputted to the optical fiber. The apparatus for suppressing the SBS includes a plurality of first transmission unit, each of which has a wavelength separation, for transmitting information signals through a signal channel; and a second transmission unit for generating and transmitting a supervisory signal of which a modulation frequency and an intensity generates a phase modulation to the plurality of information signals, through a supervisory channel.

Abstract: A wavelength aligning apparatus using an arrayed waveguide grating (AWG), and particularly, to a wavelength aligning apparatus using an arrayed waveguide grating which is capable of aligning optical sources using a transmission characteristic of an arrayed waveguide grating in a wavelength alignment method.