Abstract: A tunable semiconductor laser including a Fabry-Perot filter and an electrode array is disclosed. The propagation direction of the light beam in the cavity can be consecutively shifted applying electric field or current to the electrode and tuning can consecutively performed over the wide wavelength band by the consecutive shift of the angle of the intra cavity laser beam.

Abstract: Provided is a monolithic integrated semiconductor broad band light source. In the monolithic integrated semiconductor broad band light source, an electro absorption modulator, a semiconductor optical amplifier, and a light emitting diode are integrated on an InP substrate. Ions are implanted among the electro absorption modulator, the semiconductor optical amplifier, and the light emitting diode to electrically insulate the electro absorption modulator, the semiconductor optical amplifier, and the light emitting diode from one another. Electrodes independently implant currents into the electro absorption modulator, the semiconductor optical amplifier, and the light emitting diode. In particular, it is important to form a current intercepting layer and electrically insulate electrodes from one another but optically connect the electrodes in terms of performance of the monolithic integrated semiconductor broad band light source.

Abstract: A channel switching function is added to a wavelength division multiplexing passive optical network (WDM-PON) system, which is an access optical network system, and the potential transmission rate is increased by combining wide wavelength tunable lasers and a time division multiplexing (TDM) data structure and properly using the necessary optical components. In addition, when the wavelength of a light source or an arrayed waveguide grating (AWG) changes, the wavelength is traced and the magnitude of a transmitted signal is maximized without an additional detour line using a loop-back network structure. Furthermore, fewer thermo-electric controllers (TECs) are required for stabilizing the temperature of an optical line terminal (OLT) using wavelength tunable lasers, each laser electrically changing its wavelength.

Abstract: Provided is a coherent tuning apparatus capable of continuously tuning wavelength of light over a wide band of wavelength at high speed and outputting high power, the apparatus including an optical waveguide through which spatially coherent light passes, an electrode array for changing a direction of the light passing through the optical waveguide by applying electric field or current to a portion of the optical waveguide, and a wavelength selection optical element unit for selecting a specific wavelength of the light.

Abstract: A method of forming metal wirings for a semiconductor device. A first etch stop layer, an dielectric layer, a second etch stop layer, and a wiring layer are deposited on a semiconductor substrate. A hole is formed by etching the wiring layer, the first etch stop layer, and the dielectric layer. A trench is formed by etching the wiring layer. The exposed first and second etch stop layers are removed after removal of the trench pattern. A barrier metal layer is deposited on inner walls of the hole and the trench. Grooves are formed on the barrier metal layer. A metal seed layer is deposited on the barrier metal layer. A metal thin layer is deposited inside the hole and the trench. The metal thin layer, the metal seed layer, and the barrier metal layer on the wiring layer are removed.