Kentaro Uchiyama

Signal-to-noise ratio analysis of 100 Gb/s demultiplexing using nonlinear optical loop mirror

This paper investigates experimentally and theoretically the signal-to-noise ratio (SNR) characteristics of 100 Gb/s all-optical demultiplexing using a nonlinear optical loop mirror (NOLM). The analysis takes into account two effects that degrade the SNR associated with NOLM demultiplexing. First is channel crosstalk originating from the leakage of nontarget channels. Second is the intensity fluctuations of demultiplexed signals caused by the combined effects of timing jitter and a profile of the switching window. Considering these two effects, power penalties associated with NOLM. Demultiplexing are theoretically evaluated using the conventional noise theory of an optical receiver followed by an optical preamplifier. Experimental results of bit error rate measurements for 100 Gb/s demultiplexing using three different NOLMs with different intrinsic crosstalk values, defined by signal transmittance in the absence of control pulses, show that the power penalties are in good agreement with the evaluation based upon our proposed analysis. It can be found from our investigation in demultiplexing from 100 to 10 Gb/s that intrinsic crosstalk of less than -25 dB, corresponding to a coupling ratio, K, of |K-0.5|/spl les/0.03, is required for the power penalty of less than 1 dB. The root-mean-square (rms) value of the relative timing jitter necessary for obtaining a sufficient timing tolerance width for combining control and signal pulses is determined.

Quality monitoring of optical signals influenced by chromatic dispersion in a transmission fiber using averaged Q-factor evaluation

We evaluated the averaged Q-factor for optical signals distorted by chromatic dispersion in a transmission fiber. This letter confirms that our method has sensitivity to bit error rate degradation due to both the signal-to-noise ratio degradation of pulse distorted signals and pulse distortion itself. It also explains how fault detection in an optical network system can be done with this method.

Adaptive dispersion slope equalizer using a nonlinearly chirped fiber Bragg grating pair with a novel dispersion detection technique

We realized the first adaptive-dispersion equalizer that equalizes dispersion over a wide wavelength range (6 nm) in the zero-dispersion wavelength region of a dispersion-shifted fiber (DSF). The equalizer is based on a pair of nonlinearly chirped fiber Bragg gratings, which are designed to equalize exactly the dispersion profile of a DSF. The dispersion changes were tracked using a technique that employs opposite dispersion fibers to identify the sign of the dispersion change. Unlike previous approaches, no additional sources or changes in the source wavelength are required. We demonstrate the adaptive equalization of the dispersion changes in an 83-km DSF, induced by temperature changes between -10/spl deg/C and 60/spl deg/C.

100-Gb/s multiple-channel output all-optical OTDM demultiplexing using multichannel four-wave mixing in a semiconductor optical amplifier

We present a successful demonstration of ultra-fast all-optical time-division demultiplexing with simultaneous multiple-channel output, a vital function for all-optical demultiplexers. The demultiplexing operation is based on multichannel four-wave mixing (FWM) in a semiconductor optical amplifier. Error-free, simultaneous live-channel-output, 100-6.3-Gb/s demultiplexing is successfully performed.

3 Tbit/s (160 Gbit/s/spl times/19 ch) OTDM/WDM transmission experiment

3 Tbit/s (160 Gbit/s/spl times/19 channels) optical signal is successfully transmitted over 40 km dispersion-shifted fiber. Low noise supercontinuum signal pulse sources and 70 nm bandwidth tellurite-based optical amplifiers are used for 3 Tbit/s signal generation and amplification.

Subpicosecond timing control using optical double-pulses correlation measurement

Optical pulse timing control is very important for stabilizing extremely dense optical signal handling devices such as optical time-division multiplexers. We realize a module that offers subpicosecond pulse-timing monitoring and stabilization through the use of optical double pulses and their cross-correlation signals. A 45-ps timing drift due to the temperature change of a fiber is stabilized to within 0.8 ps without high-speed electronic circuits. This module has excellent time resolution, better than 0.1 ps, due to its stable double-pulse distance and correlation measurement mechanism.

Vibration-insensitive nonlinear optical loop mirror utilizing reflective scheme

We propose a new type of nonlinear optical loop mirror that can reduce nonreciprocal phase shifts due to external vibration. We experimentally confirm its excellent vibration by all-optical time-division demultiplexing of 100-Gb/s optical signal.

Adaptive dispersion slope equalizer for dispersion-shifted fibers using a nonlinearly chirped fiber Bragg grating pair

We realized, for the first time to our knowledge, an adaptive dispersion slope equalizer (ADSE) for dispersion-shifted fibers (DSFs). We demonstrate adaptive equalization using 2 ps pulses of the dispersion changes in an 83 km DSF, induced by temperature changes between -10/spl deg/C and 60/spl deg/C.

Bit-rate Flexible Picosecond Pulse Width Conversion with All-optical Mono-stable Multivibrator Laser Diode

An optical mono-stable multivibrator laser diode (MM-LD) is realized by using a multi-electrode distributed feedback laser diode. All-optical pulse-width conversion of ultra-short pulses to non-return-to-zero (NRZ) is achieved using an MM-LD. The MM-LD is adopted for a wide range of bit-rates between 2-10 Gbit/s by tuning the DC bias. Data format transformation from 10-Gbit/s return-to-zero optical signals to NRZ optical-signals is achieved with error free operation. Converted optical signals, which have a narrower spectral bandwidth and lower peak power than when input, are transmitted using a 1.3-μm zero dispersion fiber (1.3Aλ0-SMF).

Polarization-independent all-optical demultiplexing up to 200 Gbit/s using four-wave mixing in a semiconductor laser amplifier

Summary form only given. All-optical time-division demultiplexing (TDM) is one of the most fundamental functions in future Tbit/s all-optical networks. This paper proposes a simple polarisation independent (PI) all-optical TDM demultiplexer that utilizes the ultrafast four-wave mixing (FWM) process of both TE and TM modes in a semiconductor laser amplifier (SLA) in which input pump and signal pulses are deliberately depolarized to suppress polarization coupling.