Kidsanapong Puntsri

40-krad/s Polarization Tracking in 200-Gb/s PDM-RZ-DQPSK Transmission Over 430 km

We present real-time transmission of 50-Gbaud polarization-division-multiplexed (PDM) return-to-zero differential quadrature phase-shift keying (4 bit/symbol) over five fiber spans, 430 km in total. The two PDM channels are demultiplexed using a beam splitter and automatic optical polarization control with interference detection. For the first time, PDM signal tracking speeds of up to 40 krad/s are demonstrated.

20-Gb/s PDM-RZ-DPSK Transmission With 40 krad/s Endless Optical Polarization Tracking

An endless polarization tracker detects and minimizes interchannel interference, enabling automatic optical polarization demultiplex and consecutive direct detection of a 20-Gb/s polarization division multiplex RZ-DPSK signal at polarization scrambling speeds up to 40 krad/s. Transmission over 430 km of fiber is error-free.

Performance analysis of RF-pilot phase noise compensation techniques in coherent optical OFDM systems

In coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems, phase noise has an important impact on the system performance. They are highly sensitive to phase noise induced by transmitter laser and local oscillator laser. We explain different kinds of phase noise effects on the OFDM signals and analyze the phase noise effect induced by transmitter laser and local oscillator. We analyze the standard RF-pilot (RFP) phase noise compensation method and explain its drawbacks. We provide two extended RFP schemes that overcome the drawbacks of the standard RFP scheme and enhance the performance of CO-OFDM systems. Furthermore, the phase noise effects for various laser linewidths and the effect of the received optical power (ROP) on the system performance are quantified. A CO-OFDM transmission system with 16-QAM is simulated with VPItransmissionMaker™ V8.5.

Analysis of Partial Pilot Filling Phase Noise Compensation for CO-OFDM Systems

In coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems, phase noise of transmitter and local oscillator lasers has an important impact on system performance. In this letter, a partial pilot filling compensation scheme is analyzed and compared to conventional common phase error compensation and RF-pilot-based phase noise compensation. The effects of phase noise for various laser linewidths and of received optical power on system performance are evaluated. A CO-OFDM transmission system with 4-QAM is simulated with VPI transmissionMaker V8.7.

The robustness of subcarrier-index modulation in 16-QAM CO-OFDM system with 1024-point FFT.

We present in numerical simulations the robustness of subcarrier index modulation (SIM) OFDM to combat laser phase noise. The ability of using DFB lasers with SIM-OFDM in 16-QAM CO-OFDM system with 1024-point FFT has been verified. Although SIM-OFDM has lower spectral efficiency compared to the conventional CO-OFDM system, it is a good candidate for 16-QAM CO-OFDM system with 1024-point FFT which uses a DFB laser of 1 MHz linewidth. In addition, we show the tolerance of SIM-OFDM for mitigation of fiber nonlinearities in long-haul CO-OFDM system. The simulation results show a significant penalty reduction, essentially that due to SPM.

Fiber nonlinearity tolerance of SIM-OFDM in CO-OFDM transmission

We present the tolerance of subcarrier-index modulation OFDM which is a new method for mitigation of fiber nonlinearities in CO-OFDM transmission. Simulation results show a significant penalty reduction, essentially that due to SPM.

Hardware-Efficient Phase Estimation for Digital Coherent Transmission With Star Constellation QAM

In order to build optical transmission systems for 100 Gb/s and above on a single wavelength division multiplexing channel, transition from quadrature phase-shift keying (QPSK) to higher quadrature amplitude modulation (QAM) formats seems to be inevitable. Instead of the usual square constellation QAM, we focus on regular star constellation QAM formats and present a hardware-efficient phase-estimation algorithm that is suitable for all regular star constellations, together with preliminary simulation results.

Reduced sampling rate frequency domain CD equalization for 112 Gb/s PDM-QPSK

Frequency domain chromatic dispersion equalization is simulated for long-haul fiber transmission at 112 Gb/s. The received data is processed at a reduced fractional sampling rate of 1.6 samples per symbol with a 1.5 dB penalty.

Experimental demonstration of 1024-IFFT FPGA implementation with 3.98 Gbps throughput for CO-OFDMA-PON transmitters

This work presents a design and implementation of inverse fast Fourier transform (IFFT) for coherent optical orthogonal frequency division multiple access passive optical network (CO-OFDMA-PON) using a field-programmable gate array (FPGA). The IFFT size of 1024 is considered. The core computation is forward FFT processing. The tested hardware consists of a digital-to-analog converter (DAC) with the sampling rate of 500 Msps and the FPGA form Xilinx ML605 evaluation board. The FPGA is the key computation. For the IFFT calculation topology, the Radix-4 with 4 parallel processing units is employed. As a result, 16 inputs are calculated at the same time. By employing parallel processing, the internal FPGA clock is reduced to only 31.25 MHz (=500/16 MHz). Additionally, in this work, 256-QAM is perfectly adopted. Consequently, the net speed up to 3.98 Gbps throughput can be achieved. The hardware resources usage is.

Pilot-aided phase noise and carriers frequency offset compensation for coherent optical UFMC PON

This work presents an analysis and design of phase noise (PN) and carrier frequency offset (CFO) compensation for coherent optical universal filtered multicarrier passive optical network. It is shortly named as CO-UFMC PON. The Dolph-Chebyshev-filters is used which it gives the lowest side-lope power suppression. To estimate PN and CFO, one whole subband is employed to be pilots. The maximum likely hood method is used. The numerical simulation is employed to verify the proposed method. The results show that the side-lope power suppression of 50 dB is achieved when compared with the conventional orthogonal frequency division multiple accesses (OFDMA). The laser linewidth tolerance of 300 kHz can be achieved where the sampling rate of 10 Gsps and 4- and 16-qaurdrature amplitude modulation (QAM) are studied. 64 users (splitter 1:64) are considered to be used in this work.