Leif Katsuo Oxenløwe

Breakthrough switching speed with an all-optical chalcogenide glass chip: 640 Gbit/s demultiplexing

We report the first demonstration of error-free 640 Gbit/s demultiplexing using the Kerr non-linearity of an only 5 cm long chalcogenide glass waveguide chip. Our approach exploits four-wave mixing by the instantaneous nonlinear response of chalcogenide. Excellent performance is achieved with only 2 dB average power penalty and no indication of error-floor. Characterisation of the FWM efficiency for the chalcogenide waveguide is given and confirms the good performance of the device.

Demonstration of 5.1 Tbit/s data capacity on a single-wavelength channel.

We have generated a single-wavelength data signal with a data capacity of 5.1 Tbit/s. The enabling techniques to generate the data signal are optical time-division multiplexing up to a symbol rate of 1.28 Tbaud, differential quadrature phase shift keying as data format, and polarisation-multiplexing. For the first time, error-free performance with a bit error rate less than 10(-9) is demonstrated for the 5.1 Tbit/s data signal. This is achieved in a back-to-back configuration using a direct detection receiver based on polarisation- and time-demultiplexing, delay-demodulation and balanced photo-detection.

Nonlinear properties of and nonlinear processing in hydrogenated amorphous silicon waveguides

We propose hydrogenated amorphous silicon nanowires as a platform for nonlinear optics in the telecommunication wavelength range. Extraction of the nonlinear parameter of these photonic nanowires reveals a figure of merit larger than 2. It is observed that the nonlinear optical properties of these waveguides degrade with time, but that this degradation can be reversed by annealing the samples. A four wave mixing conversion efficiency of + 12 dB is demonstrated in a 320 Gbit/s serial optical waveform data sampling experiment in a 4 mm long photonic nanowire.

640 Gbit/s and 1.28 Tbit/s polarisation insensitive all optical wavelength conversion

We report the first demonstration of polarisation insensitive all-optical wavelength conversion (AOWC) for single wavelength channel 640 Gbit/s return-to-zero differential-phase-shift-keying (RZ-DPSK) signal and 1.28 Tbit/s polarisation multiplexed (Pol-Mux) RZ-DPSK signals using a 100-m polarisation-maintaining highly nonlinear fiber (PM-HNLF) in a polarisation diversity loop configuration. The AOWC is based on four-wave mixing in PM-HNLF. Error free performance is achieved for the wavelength converted signals. Less than 0.5 dB polarisation sensitivity is obtained.

Ultra-high-speed wavelength conversion in a silicon photonic chip

We have successfully demonstrated all-optical wavelength conversion of a 640-Gbit/s line-rate return-to-zero differential phase-shift keying (RZ-DPSK) signal based on low-power four wave mixing (FWM) in a silicon photonic chip with a switching energy of only ~110 fJ/bit. The waveguide dispersion of the silicon nanowire is nano-engineered to optimize phase matching for FWM and the switching power used for the signal processing is low enough to reduce nonlinear absorption from two-photon-absorption (TPA). These results demonstrate that high-speed wavelength conversion is achievable in silicon chips with high data integrity and indicate that high-speed operation can be obtained at moderate power levels where nonlinear absorption due to TPA and free-carrier absorption (FCA) is not detrimental. This demonstration can potentially enable high-speed optical networks on a silicon photonic chip.

Photonic chip based transmitter optimization and receiver demultiplexing of a 1.28 Tbit/s OTDM signal

We demonstrate chip-based Tbaud optical signal processing for all-optical performance monitoring, switching and demultiplexing based on the instantaneous Kerr nonlinearity in a dispersion-engineered As(2)S(3) planar waveguide. At the Tbaud transmitter, we use a THz bandwidth radio-frequency spectrum analyzer to perform all-optical performance monitoring and to optimize the optical time division multiplexing stages as well as mitigate impairments, for example, dispersion. At the Tbaud receiver, we demonstrate error-free demultiplexing of a 1.28 Tbit/s single wavelength, return-to-zero signal to 10 Gbit/s via four-wave mixing with negligible system penalty (< 0.5 dB). Excellent performance, including high four-wave mixing conversion efficiency and no indication of an error-floor, was achieved. Our results establish the feasibility of Tbaud signal processing using compact nonlinear planar waveguides for Tbit/s Ethernet applications.

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.

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.

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.