Keun Yeong Cho

Demonstration of RSOA-based WDM PON employing self-homodyne receiver with high reflection tolerance

We propose and demonstrate a 1.25-Gb/s RSOA-based WDM PON employing a novel self-homodyne receiver. The proposed receiver enables the excellent receiver sensitivity and reflection tolerance, and has potential applications in the long-reach WDM PON with high-split ratio.

103-Gb/s Long-Reach WDM PON Implemented by Using Directly Modulated RSOAs

We propose and demonstrate a long-reach wavelength-division-multiplexed passive optical network (WDM PON) capable of providing 100-Gb/s service to each subscriber, for the first time to the best of our knowledge. For cost-effectiveness, this network is implemented in loopback configuration by using directly modulated reflective semiconductor optical amplifiers (RSOAs) at 25.78 Gb/s. For the modulation of the RSOA at such a high-speed, we have to minimize the electrical parasitics by using the butterfly package. Also, to overcome the limited bandwidth of the RSOA, we utilize the electronic equalization technique at the receiver. We use four RSOAs at each optical network unit for the 103-Gb/s upstream transmission. The operating wavelengths of these RSOAs are separated by the free-spectral range of the cyclic arrayed waveguide gratings used at the central office and remote node (RN) for (de)multiplexing the WDM channels. We extend the maximum reach of this WDM PON to be >; 120 km by using Erbium-doped fiber amplifiers at the RN. The results show that the error-free transmission can be achieved for all WDM channels in the wavelength range of >; 35 nm with sufficient power margins.

Demonstration of 11-Gb/s, 20-km reach WDM PON using directly-modulated RSOA with 4-ary PAM signal

We demonstrate the error-free transmission of 11-Gb/s 4-ary PAM signal obtained by using a directly modulated RSOA over 20 km of SMF for the cost-effective realization of highspeed WDM PONs.

Demonstration of RSOA-based WDM PON Operating at Symmetric Rate of 1.25 Gb/s with High Reflection Tolerance

We demonstrate an RSOA-based WDM PON operating at the symmetric rate of 1.25 Gb/s by using a low-frequency subcarrier (2.5 GHz). The performance is robust against the remodulation noise as well as the reflection noise.

Maximum reach of long-reach RSOA-based WDM PON employing remote EDFA

We investigate the effects of the gain and position of the remote EDFA in a long-reach RSOA-based WDM PON. Using this result, we also estimate the maximum transmission reach limited by Rayleigh backscattering.

Self-polarization-stabilization technique for long-reach coherent WDM PON

We demonstrate a simple self-polarization-stabilization technique for the long-reach RSOA-based WDM PON implemented with self-homodyne receivers. The effectiveness of this technique is confirmed in 2.5-Gb/s transmission experiments over 68-km long link partially composed of installed fibers.

Reflection tolerance of RSOA-based WDM PON

We investigate the effects of back-reflection in RSOA-based WDM PON utilizing the remodulation technique. The downstream signal is likely to have severe reflection tolerance (-42 ~ -35 dB), which highly depends on the RSOA gain.

10-Gb/s, 80-km reach RSOA-based WDM PON employing QPSK signal and self-homodyne receiver

We demonstrate 10-Gb/s, 80-km-reach RSOA-based WDM PON by utilizing the digital coherent detection and electronic phase equalization techniques. The upstream signal is obtained by directly modulating a TO-can packaged RSOA with 10-Gb/s QPSK signal.

Filtering tolerance of 108-Gb/s PolMux quadrature duobinary signal on 25-GHz grid

We demonstrate the error-free transmission of 108-Gb/s PolMux quadrature duobinary signal in a 25-GHz spaced WDM system and investigate its tolerance to narrow optical filtering.

Operating Wavelength Range of 1.25-Gb/s WDM PON Implemented by using Uncooled RSOA's

We demonstrate that, by using a simple bias-control circuit, the operating wavelength range of the 1.25-Gb/s WDM PON implemented by using uncooled RSOAs can be extended to -49 nm in the temperature range of -20 ~ +60 °C.