Kun-Youl Park

A theoretical model of a wavelength-locked Fabry-Pe/spl acute/rot laser diode to the externally injected narrow-band ASE

We propose a theoretical model of the wavelength-locked Fabry-Pe/spl acute/rot laser diode (F-P LD) to the externally injected narrow-band amplified spontaneous emission. The model explains the dynamics of the wavelength-locked F-P LD. The simulation results with the proposed model show good agreement with the experimental results.

Noise Characteristics of a Wavelength-Locked Fabry–Perot Laser Diode

We derived a theoretical model of a wavelength-locked Fabry-Perot laser diode (F-P LD) to a sliced spectrum of externally injected amplified spontaneous emission (ASE) from wave equations. The model explains the dynamics of the wavelength-locked F-P LD. Using this model, we investigated the noise characteristics of a wavelength-locked F-P LD with respect to the various parameters, such as, the injected ASE power, the bias current of F-P LD, and the wavelength detuning. We also investigated intensity noise increment by spectral filtering in optical access networks based on wavelength-locked F-P LDs.

Effects of nonlinear crosstalk in optical PMD compensation

We report on the effects of nonlinear crosstalk on the optical polarization-mode dispersion (PMD) compensation in wavelength-division-multiplexing (WDM) systems. An analytical model is presented to describe the effect of nonlinear crosstalk on the first-order PMD compensation. We also experimentally show that the performance of WDM systems could be degraded by nonlinear birefringence, even when the first-order PMD is completely compensated.

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.

Intensity Noise in a Wavelength-Locked Fabry–Perot Laser Diode to a Spectrum Sliced ASE

We derived analytic expression for the relative intensity noise (RIN) of a wavelength-locked Fabry-Perot laser diode (FP LD) in a single mode region. The RIN of the wavelength-locked output is a function of the photon density and the photon life time. It also depends on the wavelength detuning and the injected amplified spontaneous emission (ASE) power. We investigated the modulation transfer function of the wavelength-locked FP LD and its dependence on wavelength detuning. The analytic result has good agreement with the simulation result.

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.

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.

WDM-PON: a next-generation access network

We discuss wishes for next generation access networks and proposed and demonstrated WDM-PONs based on wavelength locked F-P LDs. These WDM-PONs guarantee color-free (or wavelength independent) operation of ONTs and OLT transceivers. The scalability of the WDM-PON is also investigated in terms of transmission length, split ratio, and transmission speed.

Reduction of the Power Penalty Induced by Low-Frequency Tone Using Variable Decision Threshold Technique

We propose variable decision threshold technique to decrease the power penalty induced by low-frequency tones. The proposed scheme uses a simple low-speed receiver to change the decision threshold of the optical receiver according to the low-frequency tones. We demonstrate the proposed method at 2.5 Gb/s.

Analytic expressions of the modulation response and the relative intensity noise of a wavelength-locked F-P LD

We derived analytic expressions for the modulation response and the relative intensity noise of a wavelength-locked F-P LD. The analytic results have good agreement with the simulation results.