Abstract: Provided are an apparatus for generating/detecting terahertz wave and a method of manufacturing the same. The apparatus includes a substrate, a photo conductive layer, a first electrode and a second electrode, and a lens. The photo conductive layer is formed on an entire surface of the substrate. The first electrode and a second electrode formed on the photo conductive layer. The first and second electrodes are spaced from each other by a certain gap. The lens is formed on the first and second electrodes. The lens is filled in the gap between the first and second electrodes.

Abstract: Provided are a photomixer module and a method of generating a terahertz wave. The photomixer module includes a semiconductor optical amplifier amplifying incident laser light and a photomixer that is excited by the amplified laser light to generate a continuous terahertz wave. The photomixer is formed as a single module together with the semiconductor optical amplifier.

Abstract: Provided is a laser device. In the laser device, an active layer is connected to a stem core of a 1×2 splitter on a substrate, a first diffraction grating is coupled to a first twig core of the 1×2 splitter, and a second diffraction grating is coupled to a second twig core of the 1×2 splitter. An active layer-micro heater is designed to supply heat to the active layer. First and second micro heaters are designed to supply heats to the first and second diffraction gratings, respectively, thereby varying a Bragg wavelength.

Abstract: Provided is a multiple distributed feedback laser device which includes a first distributed feedback region, a modulation region, a second distributed feedback region, and an amplification region. An active layer is disposed on the substrate of the first distributed feedback region, the modulation region, the second distributed feedback region, and the amplification region. A first diffraction grating is disposed in the first distributed feedback region to be coupled to the active layer in the first distributed feedback region. A second diffraction grating is disposed in the second distributed feedback region to be coupled to the active layer in the second distributed feedback region. The multiple distributed feedback laser device further includes a first micro heater configured to supply heat to the first diffraction grating and a second micro heater configured to supply heat to the second diffraction grating.

Abstract: Provided are an apparatus for generating/detecting terahertz wave and a method of manufacturing the same. The apparatus includes a substrate, a photo conductive layer, a first electrode and a second electrode, and a lens. The photo conductive layer is formed on an entire surface of the substrate. The first electrode and a second electrode are formed on the photo conductive layer. The first and second electrodes are spaced from each other by a certain gap. The lens is formed on the first and second electrodes. The lens is filled in the gap between the first and second electrodes.

Abstract: Provided is an optical device. The optical device includes a multiplexer/demultiplexer, a multimode interference (MMI) coupler, a first waveguide, and second waveguides. The multiplexer/demultiplexer splits optical signals having a plurality of channels and received through a first port according to their wavelength to provide the split optical signals to second ports, or providing input optical signals having wavelengths difference from each other and received through the second ports to the first port. The multimode interference (MMI) coupler is connected to the first port. The first waveguide is connected to the MMI coupler. The second waveguides are connected to the second ports. The MMI coupler has a width decreasing toward the multiplexer/demultiplexer.

Abstract: Provided is a multiple distributed feedback laser device. The laser device includes an active layer, a first diffraction grating, and a second diffraction grating. The substrate includes a first distributed feedback region, a modulation region, and a second distributed feedback region. The first diffraction grating is coupled to the active layer in the first distributed feedback region. The second diffraction grating is coupled to the active layer in the second distributed feedback region. In addition, the laser device includes a first micro heater and a second micro heater. The first micro heater supplies heat to the first diffraction grating. The second micro heater supplies heat to the second diffraction grating. The first micro heater and the second micro heater are controlled independently from each other.

Abstract: Provided is an upstream source light generator of a passive optical network (PON) system. The upstream source light generator includes an amplification part configured to amplify injection light, and a reflection part configured to receive the amplified injection light and generate reflection light by reflecting the amplified injection light with different optical delays according to wavelengths of the amplified injection light.

Abstract: Provided is a semiconductor laser device including: a gain area where multi-wavelength lights are generated and gain are provided; a first reflection area where among the multi-wavelength lights, a first-wavelength light is reflected to the gain area in response to a first selection signal; a second reflection area where among the multi-wavelength lights, a second-wavelength light is reflected to the gain area; and a phase control area where a phase of the second-wavelength light is shifted in response to a phase control signal, the phase control area being disposed between the first reflection layer and the second reflection layer.

Abstract: Provided is a multiple distributed feedback laser device. The laser device includes an active layer, a first diffraction grating, and a second diffraction grating. The substrate includes a first distributed feedback region, a modulation region, and a second distributed feedback region. The first diffraction grating is coupled to the active layer in the first distributed feedback region. The second diffraction grating is coupled to the active layer in the second distributed feedback region. In addition, the laser device includes a first micro heater and a second micro heater. The first micro heater supplies heat to the first diffraction grating. The second micro heater supplies heat to the second diffraction grating. The first micro heater and the second micro heater are controlled independently from each other.

Abstract: An optical interleaver of a wavelength division multiplexing (WDM) system includes an optical coupler, first and second waveguides, a high reflection mirror, and first and second phase shifters. The coupler divides an input optical signal. The first waveguide branches off from the coupler in a first direction. The second waveguide branches off from the coupler in a second direction for providing an optical path different from that provided by the first waveguide. The high reflection mirror is disposed at an end of the first waveguide for reflecting a first optical signal incident onto the first waveguide. The first phase shifter is disposed at an end of the second waveguide for multiple-reflecting a second optical signal incident onto the second waveguide. The second phase shifter is disposed at the first or second waveguide for adjusting an optical path difference between the first and second waveguides by varying its refractive index.

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: 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: The present invention relates to a semiconductor laser, having a construction capable of tuning a wavelength, in which a sampled grating distributed feedback SG-DFB structure portion and a sampled grating distributed Bragg reflector SG-DBR structure portion are integrated. In the present invention, the refraction index are varied in accordance with a current applied to the phase control area in the SG-DFB structure portion and the SG-DBR structure portion, whereby it is possible to continuously or discontinuously tune the wavelength. Therefore, in such a wavelength tunable semiconductor laser, its construction is relatively simple, and it is relatively useful to the manufacturing and mass-producing the semiconductor laser. In addition, such a wavelength tunable semiconductor laser has an excellent output optical efficiency while making it possible to tune the wavelength of the wide band.

Abstract: Provided is a semiconductor laser including a substrate etched into a mesa structure, an active layer, clad layers, a current blocking layer, an etch-stop, an ohmic contact layer, and electrodes, and a method for manufacturing the same, whereby it is possible to improve a ratio of light output to input current by blocking a leakage current flowing outside an active waveguide in a BH laser.

Abstract: The SG-DFB laser diode of the present invention has a high output optical efficiency in comparison with a conventional wavelength tunable laser provided with Bragg reflection ends at the both ends of the gain region for the wavelength tuning as a structure capable of connecting an optical fiber directly without losing the optical wave generated at the gain region. And also, the present invention can be manufactured by the manufacturing process of a conventional wavelength tunable laser diode without reinvesting a new equipment. Further, the SG-DFB laser diode of the present invention can control a broadband wavelength with a simple circuit construction in comparison with a conventional wavelength tunable laser diode since it can vary the wavelength in continuous/incontinuous by the change of current of the each region of the phase control regions.

Abstract: The present invention relates to a semiconductor laser, having a construction capable of tuning a wavelength, in which a sampled grating distributed feedback SG-DFB structure portion and a sampled grating distributed Bragg reflector SG-DBR structure portion are integrated. In the present invention, the refraction index are varied in accordance with a current applied to the phase control area in the SG-DFB structure portion and the SG-DBR structure portion, whereby it is possible to continuously or discontinuously tune the wavelength. Therefore, in such a wavelength tunable semiconductor laser, its construction is relatively simple, and it is relatively useful to the manufacturing and mass-producing the semiconductor laser. In addition, such a wavelength tunable semiconductor laser has an excellent output optical efficiency while making it possible to tune the wavelength of the wide band.