Michael Galili

Optical Waveform Sampling and Error-Free Demultiplexing of 1.28 Tb/s Serial Data in a Nanoengineered Silicon Waveguide

This paper presents the experimental demonstrations of using a pure nanoengineered silicon waveguide for 1.28 Tb/s serial data optical waveform sampling and 1.28 Tb/s-10 Gb/s error-free demultiplexing. The 330-fs pulses are resolved in each 780-fs time slot in waveform sampling. Error-free operation is achieved in the 1.28 Tb/s-10 Gb/s demultiplexing.

Phase regeneration of DPSK signals in a silicon waveguide with reverse-biased p-i-n junction

Phase regeneration of differential phase-shift keying (DPSK) signals is demonstrated using a silicon waveguide as nonlinear medium for the first time. A p-i-n junction across the waveguide enables decreasing the nonlinear losses introduced by free-carrier absorption (FCA), thus allowing phase-sensitive extinction ratios as high as 20 dB to be reached under continuous-wave (CW) pumping operation. Furthermore the regeneration properties are investigated under dynamic operation for a 10-Gb/s DPSK signal degraded by phase noise, showing receiver sensitivity improvements above 14 dB. Different phase noise frequencies and amplitudes are examined, resulting in an improvement of the performance of the regenerated signal in all the considered cases.

OTDM-to-WDM Conversion Based on Time-to-Frequency Mapping by Time-Domain Optical Fourier Transformation

This paper reports on the utilization of the time-domain optical Fourier transformation (OFT) technique for serial-to-parallel conversion of optical time division multiplexed (OTDM) data tributaries into dense wavelength division multiplexed (DWDM) channels. The OFT is implemented by using a dispersive medium followed by phase modulation; the latter being achieved by a four-wave mixing process with linearly chirped pump pulses. Both numerical and experimental investigations of the OTDM-to-WDM conversion technique are carried out. Experimental validations are performed on 320- and 640-Gbit/s OTDM data with error-free performance.

1.28-Tb/s Demultiplexing of an OTDM DPSK Data Signal Using a Silicon Waveguide

This letter demonstrates optical demultiplexing of a 1.28-Tb/s serial differential phase-shift-keying data signal using a nano-engineered silicon waveguide. We first present error-free performance at 640 Gb/s and then at 1.28 Tb/s with characterization of all 128 channels. Bit-error rates below 10-9 are achieved for some channels and below forward-error-correction limit for all channels, corresponding to a 1.19-Tb/s error-free data signal.

640-Gbit/s Data Transmission and Clock Recovery Using an Ultrafast Periodically Poled Lithium Niobate Device

This paper presents the first demonstration of the use of a periodically poled lithium niobate device for signal processing at 640 Gbit/s. Clock recovery is performed successfully using the lithium niobate device, and the clock signal is used to control a nonlinear fiber-based demultiplexer. The full 640-Gbit/s system gives error-free performance with no pattern dependence and there is less than 1-dB power penalty after 50-km fiber transmission.

Optical Wavelength Conversion by Cross-Phase Modulation of Data Signals up to 640 Gb/s

In this paper, all-optical wavelength conversion by cross-phase modulation in a highly nonlinear fiber is investigated. Regenerative properties of the wavelength converter are demonstrated, and the effect of adding Raman gain to enhance the performance of the wavelength converter is shown. The wavelength conversion scheme is demonstrated at the record-high bit rate of 640 Gb/s.

Silicon Photonics for Signal Processing of Tbit/s Serial Data Signals

In this paper, we describe our recent work on signal processing of terabit per second optical serial data signals using pure silicon waveguides. We employ nonlinear optical signal processing in nanoengineered silicon waveguides to perform demultiplexing and optical waveform sampling of 1.28-Tbit/s data signals as well as wavelength conversion of up to 320-Gbit/s data signals. We demonstrate that the silicon waveguides are equally useful for amplitude and phase-modulated data signals.

Polarization-Insensitive 640 Gb/s Demultiplexing Based on Four Wave Mixing in a Polarization-Maintaining Fibre Loop

Polarization-insensitive 640 Gbit/s demultiplexing for OTDM data signals is demonstrated using a 100 m polarization-maintaining highly non-linear fibre. The scheme is based on four wave mixing (FWM) in a polarization-maintaining fibre loop (PMFL) with bidirectional operation. Less than 0.2 dB polarization dependence is obtained. The FWM efficiency is about -6 dB if the passive loss of the PMFL is not included. The flatness characteristic of the FWM efficiencies allows for the OTDM demultiplexing of a high speed signal with a bandwidth of 1.2 THz. Error free performance with low penalty for the demultiplexed 10 Gbit/s signal is achieved for the polarization scrambled 640 Gbit/s data signal. BER measurements and eye-diagrams show that the demultiplexed 10 Gbit/s signals with and without polarization scrambling have almost identical performance.

Flat-Top Pulse Generation by the Optical Fourier Transform Technique for Ultrahigh Speed Signal Processing

This paper reports on the generation of 1.6-ps full-width at half-maximum flat-top pulses by the optical Fourier transform technique, and the utilization of these pulses in a 320-Gb/s demultiplexing experiment. It is demonstrated how a narrow pulse having a 15-nm wide third-order super-Gaussian spectral intensity profile is mapped into a flat-top pulse resembling its spectrum by simple propagation in SMF. Theoretical and experimental descriptions are given on flat-top pulse generation, and an experimental validation of the systems performance of the pulses is carried out, demonstrating a benefit in terms of timing tolerance.

15-THz Tunable Wavelength Conversion of Picosecond Pulses in a Silicon Waveguide

We demonstrate all-optical ultra-broadband tunable wavelength conversion of 1-ps pulses based on four-wave mixing in a 3-mm-long dispersion engineered silicon waveguide. In the waveguide, an input pulse with center wavelength at 1600 nm is down-converted by 135 nm (17.3 THz) to 1465 nm. A tuning range of 115 nm (15 THz, from 1465 to 1580 nm) of the converted wavelength is demonstrated, while keeping conversion efficiency, pulse shape, and pulsewidth almost unchanged.