Samsung Electronics Co., Ltd.

Luxpert Technologies Co., Ltd.

Seoul National University

Nam-Kyoo Park

Ju-Han Lee

Uh-Chan Ryu

Jung-Hoon Shin

In-sang Song

Sang-Wook Kwon

Jong-seok Kim

Young-tack Houng

Hak-Seung Han

Suk-Mo Koo

Sun-Kyu Yu

An AD converter is provided. The AD converter includes a light source unit which provides an optical signal, at least one waveguide unit which consists of a photonic crystal and transmits the optical signal, a modulation unit which applies a RF signal to the at least one waveguide unit, thereby modulating an optical signal output from the at least one waveguide unit, and a digital conversion unit which converts the modulated optical signal to a digital signal. Accordingly, a compact-sized AD convert can be realized.

AD converter using photonic crystal

Disclosed is a gain-providing optical power equalizer which can equalize optical channel output or gain while amplifying signal output. In prior art technologies, optical power equalization has been achieved by attenuating signal output differently depending upon optical channels. However, the optical power equalizer of the present invention is characterized in that it achieves equalization of optical power by giving optical gain differently depending upon optical channels. According to the present invention, the output of optical channels can be adjusted to be flat or as desired without deteriorating signal to noise ratio.

Gain-providing optical power equalizer

The present invention relates to a waveguide amplifier which is comprised of silica or silica-related material co-doped with silicon nanoclusters and rare earth elements, and more particularly, to a waveguide amplifier with higher efficiency enhanced by top-pumping method and focusing means for pumping light. The waveguide amplifier of the present invention comprises of: (a) a substrate; (b) an optical waveguide including: a lower cladding layer formed on the substrate; a core layer which is made of silica or silica-related material co-doped with silicon nanoclusters and rare earth elements on the lower cladding layer and has a refractive index higher than that of the lower cladding; and an upper cladding layer formed on the core layer; and (c) a light source, spaced apart from the waveguide, for optically pumping the waveguide, wherein the waveguide amplifier operates by exciting the rare earth elements through electron-hole combinations in the silicon nanoclusters.

Top-pumped waveguide amplifier

A multi-stage optical amplifier for use in the transmission of optical signals over fiber when using Wavelength Division Multiplexing. Wavelength Division Multiplexing is particularly sensitive to differences in gain between channels and these differences become critical when cascaded fiber amplifiers are used to boost the signal over long distances. The present amplifier flattens the differences in gain and reduces noise figure by using multi-stage equalizing filters along the length of the transmission fiber.

Multi-stage fiber amplifier with flattened gain curves

A high-power and wide-band fiber optic light source including a first rare-earth-doped optical fiber, a second rare-earth-doped optical fiber, an optical coupler coupled between the first and second rare-earth-doped optical fiber for transmitting the input pumping light to the second rare-earth-doped optical fiber, and a pumping light source adapted to supply pumping light, as the input pumping light, to the optical coupler.

High-power and wide-band fiber optic light source

A parallel optical fiber amplifier having a configuration in which a C-band silica-based erbium-doped fiber amplifier (EDFA) stage and an L-band EDFA stage are coupled together in parallel in such a fashion that a reverse amplified spontaneous emission (ASE) light emitted from the C-band and/or L-band EDFA stage is reused as a secondary pumping source for an amplification in the L-band EDFA stage. In the optical fiber amplifier of the present invention, the reverse ASE light emitted from the C-band EDFA stage and the reverse ASE light emitted from the L-band EDFA stages supplied to the L-band EDFA stage so that they can be reused for improving the power conversion efficiency of the entire system and for reducing the noise factor thereof.

Parallel optical fiber amplifier with high power conversion

A long-band optical fiber amplifier with enhanced power conversion efficiency including a first optical fiber part provided with a pumping light source, a second optical fiber part connected with the first optical fiber part, the second optical fiber part being not provided with the pumping light source, and a reuse circuit coupled between the first optical fiber part and the second optical fiber part for utilizing amplified spontaneous emission (ASE) as a secondary pumping light source from the first optical fiber part. Preferably, the reuse circuit comprises a WDM coupler connected between the first and second optical fiber parts, and a light pumping device connected with the WDM coupler to provide the pumping light source. The first and second optical fiber parts consist of erbium-doped optical fiber, and the erbium-doped optical fiber is adjusted so as to produce a gain in the L-band.

Growing community of inventors

Seoul, South Korea

Nam-Kyoo Park