Electronics and Telecommunications Research Institute

Joon-Tae Ahn

El-Hang Lee

Kyu-Seok Lee

Hak Kyu Lee

Dong Sung Lim

Min-Yong Jeon

Kyoung-Hon Kim

The present invention provides a demultiplexer for generating a constant four-wave-mixing beam without regard to an input polarization state using a dispersion-shifted fiber that is a nonlinear material with high refractive index. A number of parts in conventional demultiplexer implementations, which are sensitive to input polarization state has been replaced with optical fibers of high polarization mode dispersion.

Polarization independent all-optical demultiplexer

A dual cavity laser having a positively mode-locked structure capable of double increasing the repetition rate of output light. The dual cavity laser includes an amplitude modulator to simultaneously generate two modulating signals with opposite phases. The dual cavity laser has a simply modified structure from that of the conventional single cavity laser to have two resonators, so that it can have a repetition rate corresponding to two times that of the single cavity laser. One of the resonators may have an adjusted optical property so as to obtain two kinds of output optical pulses with different optical properties.

Dual cavity laser

A pulsed semiconductor laser has a lower threshold current and a more stable pulse train. The structure includes a saturable absorber section has a quantum well structure for laser oscillation, a gain section, a phase control section, and a super structure grating-distributed Bragg reflector section. It uses an improved construction for overcoming problems of conventional pulsed semiconductor lasers. The improved structure includes five quantum well layers having thicknesses with respective spontaneous emission peak wavelengths of '.lambda.-2.delta.', '.lambda.+.delta.', '.lambda.+2.delta.', '.lambda.', '.lambda.-.delta.' at room temperature from their upper section. .lambda. denotes the mean wavelength of the oscillating pulse laser, and .delta. denotes a fixed value less than 12 nm. The super structure grating-distributed Bragg reflector section has five sampling sections, with each section having five kinds of different pitches arranged in order of thicknesses of 25 cycles, 5 cycles, 25 cycles, 5 cycles, and 25 cycles.

Growing community of inventors

Daejeon, South Korea

Joon-Tae Ahn