Jin-Serk Baik

Fault-detection technique in a WDM-PON.

We propose and demonstrate a new in-service fault-localization method for a wavelength division multiplexing passive optical network (WDM-PON). This scheme uses a tunable OTDR realized by a wavelength-locked Fabry-Perot laser diode. We successfully detect the faults both at the feeder fiber and the drop fibers. The resolution and the dynamic range are 100 m and 12 dB, respectively. In addition, the crosstalk induced by the OTDR signal to the transmission data is negligible.

Broad-band light source using mutually injected Fabry-Pe/spl acute/rot laser diodes for WDM-PON

We propose and demonstrate a new broad-band light source (BLS) for a wavelength division multiplexing-passive optical network (WDM-PON) based on the wavelength locked Fabry-Pe/spl acute/rot laser diodes (F-P LDs). By mutual injection between two antireflection-coated F-P LDs, we realized a broad-band light with a low relative intensity noise. By using the proposed BLS for wavelength locking of the F-P LD, we achieve color-free operation of the optical network termination with Manchester coded data. We also demonstrate a WDM-PON based on the proposed BLS.

Color-free operation of dense WDM-PON based on the wavelength-locked fabry-Pe/spl acute/rot laser diodes injecting a low-noise BLS

We demonstrate color-free operation of a dense wavelength-division-multiplexing passive optical network based on the wavelength-locked Fabry-Peacuterot laser diodes with injection of a low-noise broadband light source (BLS). The color-free operation, i.e., wavelength-independent operation, was obtained at 50-GHz channel spacing with the help of a narrow injection bandwidth of the low-noise BLS. We also demonstrate three-channel upstream transmission with 100-Mb/s Manchester coded data

Wavelength self-managed optical WDM source using polarization-multiplexed Fabry-Perot laser diodes

We propose and demonstrate a novel wavelength self-managed optical source for access networks. By polarization multiplexing with two Fabry-Pe/spl acute/rot laser diodes, we can largely reduce wavelength and polarization dependence on the injected amplified spontaneous emission (ASE) light. The worst case power penalty incurred by the wavelength detuning can be decreased within 1 dB. We can obtain not only increased signal power and signal-to-noise ratio but also widened operation range. Even though polarized ASE light is used, data transmission is possible using the proposed source. Therefore, the proposed source is very practical to use in low-cost optical wavelength-division-multiplexing access networks.

Fault-localization in WDM-PONs

We propose and demonstrate a fault-localization method in wavelength division multiplexing passive optical networks. We detect the fault position using a wavelength-locked Fabry-Perot laser diode as a tunable probe light.

Hybrid WDM/SCMA-PON using wavelength-locked fabry-Pe/spl acute/rot laser diodes

We propose a large-capacity hybrid passive optical network (PON) with a wavelength-sharing technique achieved by applying subcarrier multiple access on each single channel of a wavelength-division-multiplexed (WDM) PON. We also use forward-error correction to reduce the effect of optical beat interference noise. We demonstrate three-subchannel sharing in a 100-GHz-spaced WDM-PON to accommodate three times more subscribers simultaneously at a fully dedicated connection rate of 125 Mb/s

Effects of the Injected ASE Bandwidth on the Performance of Wavelength - locked Fabry - Perot Laser Diodes

We investigate effects of the injected ASE (Amplified spontaneous emission) bandwidth on the performance of the wavelength-locked Fabry-Perot laser diodes (F-P LDs) under constant injection power density and constant injection power. For the constant injection power density, we can determine the minimum injection bandwidth by the required intensity noise or the bit-error rate (BER) performance. On the other hand, there exists the optimal ASE bandwidth for the constant injection power to minimize the intensity noise.

A WDM-PON Employing Fabry–PÉrot Laser Diodes Without a Seed Light Injection

We propose and demonstrate a wavelength-division-multiplexed passive optical network by employing double-contact Fabry-Perot laser diodes (F-P LDs) without a seed light injection. To avoid the high mode partition noise at low frequency, we use a binary phase-shift keying as a modulation format at a low relative intensity noise window. An error-free transmission is achieved by compensating a lasing envelope shift due to temperature variation with the double-contact F-P LD.

A method of lifeline communication in WDM passive optical networks

We propose and demonstrate a novel method of lifeline communication, providing an emergency voice communication channel for fiber-to-the-home based on wavelength-division multiple-access passive optical network (WDM-PON). The WDM-PON is realized with wavelength-locked Fabry-Pe/spl acute/rot laser diodes. The total power consumption for lifeline communication is estimated at about 20 mW including 10 mW on the laser. The lifeline can be maintained for about 20 h with a conventional coin type battery.

Analysis of penalty due to low-frequency intensity modulation in optical transmission systems

The low-frequency intensity modulation in optical transmission systems can occurred by optical performance monitoring or dynamic devices such as acoustooptic tunable filters. Using a conventional receiver model, we derived the optical signal-to-noise ratio (OSNR) and Q penalties due to the low-frequency intensity modulation. The penalty is a function of the extinction ratio, OSNR, the modulation index, and the number of pilot-tone signals. The analytic results show good agreement with the experimental results.