Abstract: Provided is a dispersion-shifted fiber for an optical parametric amplifier. The dispersion-shifted fiber is a silica-based optical fiber and has a large nonlinear coefficient and a small effective area. The dispersion-shifted fiber also reduces a bending loss and a splice loss due to a mode field diameter difference between it and a conventional single mode fiber. For this, the dispersion-shifted fiber comprises a rectangular core with a very small radius and a high refractive index, a depressed inner clad, and an outer clad with a ring. The core and/or the inner clad are/is doped with a heavy metal.

Abstract: Provided are an encoder and/or decoder for an OCDMA (optical code division multiple access) and a method thereof. The encoder and/or decoder includes: a demultiplexer outputting multi-wavelength optical signals through paths varying with a wavelength using a plurality of first fused couplers having different coupling coefficients; and a multiplexer selecting the signals of predetermined wavelengths out of output signals from the demultiplexer using a plurality of second fused couplers symmetric to the plurality of first fused couplers and generating a PN code corresponding to the selected wavelengths.

Abstract: Provided are a Raman amplifier and a Raman pumping method. A light source unit outputs a pumping light having a wavelength that periodically changes. A light intensity control unit varies a light intensity of the pumping light using the pumping light to improve the gain flatness of a Raman gain. A control unit directs the light intensity control unit to control the light intensity of the pumping light in synchronization with changes in the wavelength of the pumping light.

Abstract: Provided are an acousto-optic filter and an optical code division multiple access (CDMA) system using the acousto-optic filter. The acousto-optic filter includes: an acousto-optic mode converter (AOMC) converting an optical signal of a specific optical frequency corresponding to a frequency of an electric signal of an optical signal of a first mode having a predetermined optical frequency band; and a mode stripper (MS) stripping an optical signal of the optical signal of the first mode that has been converted to a second mode.

Abstract: Provided are an apparatus and a method for reducing a signal noise of an OCDMA receiver and an OCDMA receiver and method. The includes: a clock recovery unit extracting sine wave clock from an output signal of an OCDMA decoder including an MAI (multiple access interference) noise; a time gating unit separating an auto-correlation peak signal and the MAI noise from the output signal of the OCDMA decoder using the sine wave clock; and an optical interferometer removing an SI (signal interference) noise remaining in the auto-correlation peak signal.

Abstract: An apparatus and a method for generating an optical carrier is disclosed. The apparatus includes: a light source generating a pump light; a SBS generator for stimulated Brillouin scattering the pump light to generate a stokes light from the light source; an attenuator for controlling an amplitude of the pump light from the light source to generate an amplitude controlled pump light; and a detector for heterodyne beating the stokes light and the amplitude controlled pump light to generate an optical carrier.

Abstract: Provided is an erbium-doped fiber amplifier reducing transient phenomena of a signal-to-noise ratio and a bit error rate in a dynamic wavelength division multiplexing system and an amplifying method using the erbium-doped fiber amplifier. The erbium-doped fiber amplifier includes: a polarization scrambler modulating a polarization state of an input signal to remove a polarization of the input signal; an amplifier amplifying the input signal from which the polarization has been removed; a detector reading powers of input and output signals of the amplifier; and an automatic gain controller controlling currents of the pump LDs according to the powers of the input and output signals read by the detector 1630 to maintain the gain even if the power of input signal changes.

Abstract: The optical add/drop multiplexer of the present invention includes an optical splitting means dividing a wavelength division multiplexed optical signal into a pass path and a drop path; a first wavelength selection switching means receiving the dropped optical signal, demultiplexing the received optical signal, and switching a specific wavelength to one drop port; a channel equalizing means blocking the dropped optical signal, and passing a signal of remaining. wavelengths therethrough while causing the intensity thereof to be uniform; a second wavelength selection switching means receiving a plurality of optical signals through respective input ports, demultiplexing the received optical signals, and switching a specific wavelength to one add port; and an optical coupling means recombining an optical signal passed through the channel equalizing means and the optical signal output from the second wavelength selection switch.

Abstract: An apparatus and a method for generating an optical carrier is disclosed. The apparatus includes: a light source generating a pump light; a SBS generator for stimulated Brillouin scattering the pump light to generate a stokes light from the light source; an attenuator for controlling an amplitude of the pump light from the light source to generate an amplitude controlled pump light; and a detector for heterodyne beating the stokes light and the amplitude controlled pump light to generate an optical carrier.

Abstract: Provided are a Raman amplifier and a Raman pumping method. A light source unit outputs a pumping light having a wavelength that periodically changes. A light intensity control unit varies a light intensity of the pumping light using the pumping light to improve the gain flatness of a Raman gain. A control unit directs the light intensity control unit to control the light intensity of the pumping light in synchronization with changes in the wavelength of the pumping light.

Abstract: Provided is a dispersion-shifted fiber for an optical parametric amplifier. The dispersion-shifted fiber is a silica-based optical fiber and has a large nonlinear coefficient and a small effective area. The dispersion-shifted fiber also reduces a bending loss and a splice loss due to a mode field diameter difference between it and a conventional single mode fiber. For this, the dispersion-shifted fiber comprises a rectangular core with a very small radius and a high refractive index, a depressed inner clad, and an outer clad with a ring. The core and/or the inner clad are/is doped with a heavy metal.

Abstract: Optical fiber amplifier with wide input power dynamic range is employed to make a first gain block and an optical fiber pumped by Raman pump have opposite spectral gain profiles each other, thereby obtaining flat output gain profile. The optical fiber amplifier includes: a first and a second gain blocks, wherein each gain block has a gain medium and at least one optical pump; an optical fiber disposed between the first and the second gain blocks; a Raman pump for generating a pumping light; and a coupling means for coupling the pumping light to the optical fiber.

Abstract: An organic micro-cavity lasers which can reduce an optical loss and derive the lasing by the electrical pumping is disclosed. The laser of the present invention has a bottom mirror layer formed on a substrate, a bottom electrode formed on the bottom mirror layer, an active layer formed on the bottom electrode, a top electrode formed on a peripheral portion of the active layer and a top mirror layer formed on the active layer except the peripheral portion. Therefore, the laser of the present invention can greatly reduce the optical loss since it has the bottom mirror layer, the active layer and the top mirror layer. Also, the injection of current can sufficiently accomplished because the top electrode having a ring shape is formed at the peripheral portion of the active layer so as to inject the current to the active layer.

Abstract: The present invention relates to a bi-directional optical add/drop multiplexer used in a bi-directional optical transmission system. The bi-directional optical add/drop multiplexer comprises circulators, optical amplifiers, drop filters, add filters and optical isolators and is capable of adding and dropping the desired optical signal channels at the specific node in the optical transmission system for transmitting signals in bi-direction through one optical fiber, and in addition, even if the light proceeding in the opposite direction reflected and inputted due to Rayleigh Scattering and the connector reflection, the light can be removed by means of arrangement of the reflection type filters in the bi-directional optical add/drop multiplexer, thereby preventing the deterioration of the transmission efficiency.

Abstract: A bias voltage stabilizing method for an electricity-optical modulator based on an off-level sampling is disclosed.

Abstract: An organic light emitting diode having a lower electrode formed on a glass substrate, and an emissive layer and an upper electrode formed atop each other on the lower electrode. A thin insulating layer is disposed between the emissive layer and the lower or upper electrode. The thin insulating layer has a thickness within a range where tunneling occurs. The thin insulating layer is inserted between the emissive layer and electrode, so as to balance the injection of electrons a holes into the emissive layer.