T. Murakawa

Flexible power-efficient Nyquist-OTDM transmitter, using a WSS and time-lens effect

Power-efficient, flexible, Nyquist 4.88-ps sinc-pulses generation and OTDM multiplexing is demonstrated, using fractional Fourier transform subcarriers and time-lens effect. OTDM users are generated and multiplexed by a WSS, without rectangular spectral shaping.

Fractional OFDM based transmitter and receiver for time/frequency multiplexing in gridless, elastic networks

We demonstrate for the first time optical fractional OFDM system, based on intermediate grids between time and frequency axes. Using reconfigurable wavelength selective switches, we demonstrated open eye diagrams, and performance below the FEC-limit.

PAPR management of all-optical OFDM signal using fractional fourier transform for fibre nonlinearity mitigation

We propose a novel PAPR management technique using fractional Fourier transform subcarriers and time-lens effect. By deforming a high PAPR OFDM signal into a low PAPR Nyquist pulse train in fibre links, signal distortions by a fibre nonlinearity are mitigated.

Advanced Optical Pulse Signal Profiling using Distributable “Optical Pulse Ruler”

We propose and demonstrate advanced optical pulse signal profiling using a high-nonlinear optical fiber, which works as a distributable “optical pulse ruler”. Additionally, we assess its profiling performance by comparison with conventional instruments.

OFDM to OTDM conversion by fractional Fourier transform

A pioneering energy-efficient all-optical system to transform an OFDM signal into an OTDM data flow is proposed and experimentally demonstrated for the first time, based on an innovative fully passive AWG device that implements the fractional Fourier transform.

OFDM to OTDM Conversion by Optical Fractional Fourier Transform

A new AWG device has been designed and fabricated to implement the fractional Fourier transform and allow all-optical spectral and time signal manipulation. 12-channel OFDM to OTDM conversion has been experimentally demonstrated.

Cyclic prefix insertion for all-optical fractional OFDM

We verify an insertion effect of cyclic prefix for reduction of inter channel interference in all-optical fractional OFDM system. Since fractional OFDM has an intermediate characteristic between OFDM and Nyquist-OTDM, a certain degree of effect of cyclic prefix is expected in fractional OFDM. The results of bit error rate measurement of a 4×10 Gbit/s DBPSK all-optical fractional OFDM system show that cyclic prefix improves the signal quality under an insufficient time gate condition.

Break even point analysis of photonic analog-to-digital conversion on power consumption

We describe our proposed approaches for photonic analog-to-digital conversion to pursue an alliance between electronic and photonic technologies. A breakeven point analysis in terms of power consumption is briefly achieved to discuss whether or not it would be viable.

Effect maximization of quantization step slicing approach for resolution improvement in optical quantization

We experimentally examine the scalability of the resolution improvement method using quantization step slicing approach. According to the result of scalability assessment for 3-bit optical quantization system, the resolution was successfully maximized to 5 bit.

Load mitigation of chromatic dispersion estimation using WSS-based chirp indicator

We experimentally demonstrated a practical CD monitoring using a 4-channel wavelength selective switch (WSS) as a chirp indicator. The experimental result shows that the WSS-based chirp indicator monitored residual CD of 8 ps/nm (equivalent to 500 m). As a result, we confirmed that the WSS-based chirp indicator reduced the estimation range of CD 4 times.