Kazuumi Koguchi

43 Gb/s DQPSK pre-equalization employing 6-bit, 43GS/s DAC integrated LSI for cascaded ROADM filtering

Electronic pre-equalization for 43 Gb/s DQPSK has been demonstrated for the first time. Waveform distortion caused by bandwidth narrowing to 18.1 GHz by cascaded 10 Gb/s ROADMs has been adequately pre-equalized by a SiGe-BiCMOS LSI with 6-bit, 43 GS/s digital-to-analog converters.

An energy-efficient and elastic optical multiple access system based on coherent interleaved frequency division multiple access

This paper proposes a novel bandwidth-elastic and energy-efficient passive optical network (PON) based on the coherent interleaved frequency division multiple access (IFDMA) scheme. We experimentally demonstrate the coherent IFDMA-PON uplink transmission up-to 30 Gbps over a 30 km standard single-mode fiber with 2 × optical network units (ONUs). A low-complexity digital carrier synchronization technique enables multiple access of the ONUs on the basis of 78.1 MHz narrow band orthogonal subcarriers without any guard-bands.

43 Gb/s DQPSK transmission over fibre with 2450 ps/nm of dispersion using electronic pre-equalization

Electronic pre-equalization of chromatic dispersion for 43 Gb/s DQPSK has been demonstrated employing a developed test chip. The chip enables the BER in fibre with 2450 ps/nm of dispersion to be improved to 7.6E-05 without an optical dispersion compensator.

3×ONU no-guard-band coherent OFDMA-PON uplink over 40km SMF link using real-time IFDMA transmitter with free-running 100kHz linewidth source

3×ONU coherent OFDMA-PON uplink transmission is demonstrated using a 3 Gbaud realtime IFDMA transmitter. The digital remote laser synchronization technique enables no-guard-band subcarrier multiplexing with free-running ~100 kHz linewidth sources over a 40 km SMF link.

Elastic and green optical access based upon coherent interleaved frequency division multiple access (IFDMA)

We present a novel bandwidth-elastic and power-efficient coherent NG-PON based on coherent interleaved frequency division multiple access (IFDMA) and experimentally demonstrate the 2xONUs uplink transmission, exhibiting capabilities of the elastic bandwidth provisioning and CFO compensation.

Implementation of power-efficient ONU for elastic-bandwidth IFDMA-PON uplink by employing polar-coordinate transformed PSK mapping [invited]

We present an implementation of a power-efficient optical network unit (ONU) for elastic-bandwidth coherent interleaved frequency-domain multiple access passive optical network (IFDMA-PON) uplink. The ONU for a 12 Gbps quadrature phase-shift keying (QPSK) signal is implemented on a 40 nm copper CMOS process field programmable gate array. By employing polar-coordinate transformed mapping of the PSK signal, the circuit size of the ONU is drastically reduced. The power consumption of the real-time IFDMA modulation circuit is 0.82 W, which achieves 90% reductionin power consumption compared to conventional OFDMA-PON systems. Finally, elastic-bandwidth QPSK signal generations and error-free detection are experimentally demonstrated: 6 Gbps at ONUs 1 and 2, 3 Gbps at ONU1, and 9 Gbps at ONU2.

Experimental demonstration of 2xONU 30Gbps digitally-supported-coherent IFDMA-PON uplink

Coherent Interleaved FDMA (IFDMA)-PON uplink transmission with 30Gbps-8PSK format over 20km SSMF is experimentally demonstrated. Digital carrier frequency offset pre-compensation technique enables coherent orthogonal subcarrier multiple access of 2 ONUs with free-running sources.

3 × ONU No-Guard-Band Coherent OFDMA-PON Uplink Demonstration Using a Real-Time Transmitter With a Free-Running 100-kHz-Linewidth ECL

In this study, we demonstrate coherent OFDMA-PON uplink transmission experimentally using three optical network units including a 3-Gbaud real-time transmitter prototype. Cooperative digital signal processing at the ONUs and an optical line terminal enable no-guard-band subcarrier-based multiple access with free-running up to 100-kHz-linewidth external cavity lasers over a 40-km fiber link. In addition, we demonstrate the OFDMA-PON uplink with multiformatted and unequally-allocated subcarriers over up to 65-km link to verify the bandwidth flexibility of the proposed uplink. We then extend the experimental results to cases with >3 ONUs via numerical simulation.

A study on low-PAPR non-zero crossing 16-QAM modulation for 20 Gb/s-based NG-PON

We propose a new low-PAPR 16-QAM modulation using a non-zero crossing mapping for NG-PON. With this 16-QAM signal and SOA booster, a high loss budget of 29.4 dB at 20 Gb/s, which is higher by 0.9 dB than that of the normal mapping, was achieved.

A study on pre-equalization performance affected by imperfection of driving waveform

We introduce three models of imperfection of pre-equalized analog waveforms. The simulation results show the nonlinearity and the skew of the analog waveforms become the important factor to achieve the optimum performance in pre-equalization systems.