Myeonggyun Kye

Pulsed-ASE-seeded DWDM optical system with interferometric noise suppression

We propose and demonstrate a 10-Gb/s dense wavelength-division-multiplexing (DWDM) optical system based on a pulsed-seed-light source employing a fiber-based Mach-Zehnder interferometer (F-MZI) as an intensity noise suppressor. The transmission results show that the required injection power into a reflective modulator was as low as -18 dBm. The F-MZI can accommodate the polarized seed-light with superior noise characteristics so that the supported DWDM systems double using a single conventional unpolarized seed-light. In addition, an allowable length of the drop fiber is investigated to show the system flexibility.

Reduction of mode partition noise of FP-LD by using Mach-Zehnder interferometer for RSOA-based DWDM applications.

We investigate reduction of mode partition noise of a spectrally sliced Fabry-Perot laser diode (FP-LD) for application to seeded DWDM systems. The proposed scheme for the noise reduction incorporates a fiber-based Mach-Zehnder interferometer (MZI) and a reflective semiconductor optical amplifier (RSOA). The MZI enables to reduce a relative intensity noise (RIN) more than 3 dB with better noise distributions. Experimental results of 10-Gb/s signal transmission exhibit a considerable bit-error-rate (BER) reduction by three orders of magnitude at the given received power. After the noise reduction, the FP-LD is applied to a 10-Gb/s DWDM system as a seed-light-source. In a local-seeding scheme, return-to-zero (RZ) and carrier-suppressed (CS)-RZ signal formats are compared as a function of transmission distance. Furthermore, a back-reflection induced impairment is evaluated in a remote-seeding scheme. We also count the number of useable channels to show the feasibility of DWDM transmission.

Feed Forward Noise Suppression for ASE-Seeded WDM Systems

We investigate feed forward noise suppression for ASE-seeded WDM systems in relation to its limitations. In particular, limitation factors such as background ASE of reflective light sources and filtering effect are thoroughly investigated. We also measure the penalty induced by feed forward parameter variation from the designed value. Although the BER performance is improved by noise suppression, the statistical noise distribution change reduces the effectiveness of noise suppression.

Injection-locked dual fabry-perot laser diodes for interferometric noise suppression

We propose and demonstrate a reduction of mode partition noise of an F-P LD using a fiber-based Mach-Zehnder interferometer (MZI). Injection-locked dual F-P LDs suppress polarization dependence to reduce a noise power by 3-dB.