Abstract: Provided is an integrated semiconductor light source using locking characteristic by an external light injection, including: an active region controlling an optical gain and an optical output by current injection; and a passive region having a structure integrated with the active region and moving a cavity mode by current injection or voltage application to lock injection light.

Abstract: Provided is a buried ridge waveguide laser diode that has improved temperature characteristics and can reduce optical loss by a leakage current. The buried ridge waveguide laser diode includes: a ridge region that extends vertically with a constant width and is composed of a selective etching layer and a first compound layer formed of a first conductive type material on a portion of the clad layer; and a p-n-p current blocking layer that has a thickness identical to the depth of the ridge region on the clad layer outside the ridge region and includes a second compound layer formed of a second conductive type material opposite to the first conductive type material. At this time, the current blocking layer includes the first compound layer extending on the second compound layer.

Abstract: A wavelength tunable laser diode using a double coupled ring resonator is provided. A new double coupled ring resonator structure is formed by a connection of two ring resonators having different radii so that stable laser oscillation occurs only in a resonant wavelength at which the two ring resonators are simultaneously resonated, and the effective refractive index of the two ring resonators is properly controlled differently for tunable laser oscillation wavelengths. The reproducibility of the optical coupling characteristics of the passive waveguides and the ring resonator can be assured by multi-mode couplers. This results in improved manufacturing productivity of the wavelength tunable laser diode. It is possible to amplify and output an output light without having an effect on oscillation wavelength characteristic by means of an optical amplifier integrated in an output end.

Abstract: Provided is a wavelength selective switch (WSS), and more particularly, a wavelength selective switch for electrically switching a wavelength without physical displacement. The wavelength selective switch includes an optical demultiplexer for dividing an input optical signal into signals having wavelengths corresponding to respective channels, selecting either the optical signal of each channel obtained by dividing the input optical signal or an optical signal input via an add port, and outputting the selected optical signal; and an optical multiplexer including an optical deflecting unit for individually deflecting the optical signals of the respective channels received from the optical demultiplexer according to supplied current or applied voltage, wherein the optical signal of each channel deflected by the optical deflecting unit is output to a specific output port.

Abstract: Provided is a frequency-tunable terahertz light source device. The frequency-tunable terahertz light source device satisfies a Littrow diffraction condition at a wavelength and simultaneously satisfies a Littman-Metcalf diffraction condition at another wavelength using a double diffraction grating having two grating periods. Thus, oscillations simultaneously occur at the two different wavelengths, such that a terahertz wave can be stably generated by beating of the two oscillation wavelengths. In addition, the frequency-tunable terahertz light source device can readily change a frequency up to several terahertz and can be fabricated in a small size.

Abstract: A wavelength selective switch is provided. The wavelength selective switch according to the present invention comprises: an optical demultiplexer for separating an incident light with a plurality of wavelengths multiplexed into a plurality of wavelength lights and outputting the separated wavelength lights; an optical amplifier for selectively amplifying or absorbing the separated wavelength lights; an optical deflector for selectively deflecting outputs of the optical amplifier; and an optical multiplexer for multiplexing the selectively deflected lights and outputting the multiplexed lights.

Abstract: Provided is a long cavity single-mode laser diode in which a ring waveguide is integrated such as a conventional array waveguide (AWG)-based laser or a concave grating (CG)-based laser.

Abstract: Provided is a long cavity single-mode laser diode in which a ring waveguide is integrated such as a conventional array waveguide (AWG)-based laser or a concave grating (CG)-based laser.

Abstract: Provided is an optical deflector for deflecting radiation beams. The optical deflector includes: a peripheral region having a first effective refractive index; and a deflection pattern region having a predetermined shape and a second effective refractive index, wherein the second effective refractive index differs from the first effective refractive index. Here, due to the deflection pattern region having the predetermined shape, the radiation beams are deflected in a direction starting from a certain point. By using the optical deflector, the locus of a light source can be designed in one of various forms, such as a straight line, a circle, an ellipse, or a parabola.

Abstract: Provided is a tunable external cavity laser diode using a variable optical deflector wherein the variable optical deflector, in which a refractive index varies according to an electrical signal, is arranged in a triangular shape between a concave diffraction grating and a reflective mirror. Since a resonant frequency is changed using the electrical signal rather than the mechanical movement, the stable operation and continuous high-speed tenability may be enabled. In addition, when the tunable external cavity laser diode according to the present invention is implemented in an InP/InGaAsP/InP slab waveguide, a variable time determined by the carrier lifetime may be reduced to several nanoseconds or less, the miniaturization is enabled, and the manufacturing costs are significantly reduced due to the process simplification.

Abstract: Provided is a buried ridge waveguide laser diode that has improved temperature characteristics and can reduce optical loss by a leakage current. The buried ridge waveguide laser diode includes: a ridge region that extends vertically with a constant width and is composed of a selective etching layer and a first compound layer formed of a first conductive type material on a portion of the clad layer; and a p-n-p current blocking layer that has a thickness identical to the depth of the ridge region on the clad layer outside the ridge region and includes a second compound layer formed of a second conductive type material opposite to the first conductive type material. At this time, the current blocking layer includes the first compound layer extending on the second compound layer.

Abstract: Provided are a tunable demultiplexer and a tunable laser, having an optical deflector in which a refractive index of a core layer of a deflection pattern region having a predetermined shape varies in response to an external electrical signal so that the optical deflector deflects incident light in the radial direction.

Abstract: An optical modulator using a dynamic single mode laser diode (DSM-LD) integrated with a deflector is disclosed. The optical modulator for coupling a light beam to an optical fiber, the optical modulator includes: a laser diode for generating the light beam; and a deflector for deflecting a direction of the light beam according to an electric signal externally applied and outputting the defected light beam to the optical fiber, wherein the laser diode and the deflector are integrated with a multi-layer semiconductor structure in such a way that the light beam is modulated by changing a defection angle of the deflector.

Abstract: Provided is a wavelength tunable light source that can electrically tune wavelengths by monolithically integrating an optical amplifier, a beam steering unit, and a concave diffraction grating on a single substrate. A beam is deflected by the beam steering unit when an electrical signal is applied to two electrodes installed in the beam steering unit to be incident on the diffraction grating, and then diffracted by the diffraction grating according to the incidence angle such that part of the beam with a specific wavelength is reflected, thereby achieving wavelength tuning. Since the wavelength tuning is achieved electrically, the wavelength tunable light source is structurally stable and has a rapid wavelength tuning rate.

Abstract: Provided is an integrated semiconductor light source using locking characteristic by an external light injection, including: an active region controlling an optical gain and an optical output by current injection; and a passive region having a structure integrated with the active region and moving a cavity mode by current injection or voltage application to lock injection light.

Abstract: Provided are a tunable demultiplexer and a tunable laser, having an optical deflector in which a refractive index of a core layer of a deflection pattern region having a predetermined shape varies in response to an external electrical signal so that the optical deflector deflects incident light in the radial direction.

Abstract: Disclosed is a high speed optical signal processor which includes a saturable absorber area including a substrate, an active layer, a clad layer and a first upper electrode which are sequentially formed on one face of the substrate, and a first lower electrode formed on the other face of the substrate; and a gain-clamped optical amplifier area including a substrate having a diffraction grating for generating a laser beam, an active layer, a clad layer and a second upper electrode which are sequentially formed on one face of the substrate, and a second lower electrode formed on the other face of the substrate, the second upper electrode being isolated from the first upper electrode of the saturable absorber area.

Abstract: An optical modulator using a dynamic single mode laser diode (DSM-LD) integrated with a deflector is disclosed. The optical modulator for coupling a light beam to an optical fiber, the optical modulator includes: a laser diode for generating the light beam; and a deflector for deflecting a direction of the light beam according to an electric signal externally applied and outputting the defected light beam to the optical fiber, wherein the laser diode and the deflector are integrated with a multi-layer semiconductor structure in such a way that the light beam is modulated by changing a defection angle of the deflector.

Abstract: The present invention relates to all-optical OR and XOR logic elements employing saturable absorbers as optical gates. Saturable absorbers are arranged in paths of the Mach-Zehnder interferometer, respectively. If the total power of an input optical signal and a continuous wave signal is higher than a transparent input power of the saturable absorbers, the input optical signal passes through the saturable absorbers, and then the optical signals through the two paths are combined, so that it is possible to obtain the operational characteristics of the OR and XOR logic elements. According to the present invention, unlike the optical logic element using a cross-phase modulation by a semiconductor optical amplifier, phase difference depending upon the input optical power is not generated between two paths, so that it is possible to alleviate a restriction of an allowable range of the input optical power.

Abstract: Disclosed is a tunable wavelength semiconductor laser diode which comprises a FP(fabry-parrot) laser diode array for producing at least two light beams, a combiner for combining the light beams output by an end of the laser diode array, a lens for collimating the light beams output by another end thereof, a grating for diffracting the light beams collimated by the lens, and a reflector for reflecting the light beams diffracted by the grating to feed the reflected light beams back to the laser diode array.