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As the bit rates of optical networks increase, the ability of accurate monitoring of optical waveforms has become increasingly important. In recent years, optical sampling has emerged as a technique to perform time-resolved measurements of optical data signals at high data rates with a bandwidth that cannot be reached by conventional photodetectors and oscilloscopes. In an optical sampling system, the optical signal is sampled in the optical domain by a nonlinear optical sampling gate before the resulting samples are converted to an electrical signal. This avoids the need for high bandwidth electronics if the optical sampling gate is operated with a modest repetition frequency. In this paper, we present an optical sampling system using the optical Kerr effect in a highly nonlinear chalcogenide device, enabling combined capability for femtosecond resolution and broadband signal wavelength tunability. A temporal resolution 450-fs is achieved using four-wave mixing (FWM) in dispersion-engineered chalcogenide waveguides: on one hand a 7-cm long planar waveguide (integrated on a photonic chip) and on the other hand a 5-cm long tapered fiber. The use of a short length, dispersion-shifted waveguide with ultrahigh nonlinearity (10000/W/km) enables high-resolution optical sampling without the detrimental effect of chromatic dispersion on the temporal distortion of the signal and sampling pulses, as well as their phase mismatch (which in turn would degrade the FWM efficiency and the sensitivity of the measurement). Using these chalcogenide devices, we successfully monitor a 640-Gb/s optical time-division multiplexing (OTDM) datastream, showcasing its potential for monitoring of signals at bitrates approaching and beyond Tb/s. We compare the advantages and disadvantages of both approaches and discuss fundamental limitations as well as potential improvements.

We report the first demonstration of all-optical Tbaud switching on a compact photonic chip. A 1.28 Tbaud return-to-zero signal was demultiplexed via four-wave mixing in a highly nonlinear, dispersion-engineered 7-cm Chalcogenide planar waveguide.

We directly investigate the influence of nonlinear loss dynamics on a slow-light silicon waveguide optical limiter, mapping how the response of free carrier absorption varies as intensity changes approach the free carrier recombination time.

We review the latest advances in dispersion-shifted, highly nonlinear planar rib waveguides fabricated in As2S3 glass for enabling broadband wavelength conversion and phase conjugation of high-speed, phase shift keyed signals via CW pumped four-wave mixing.

We demonstrate multi-impairment monitoring of 640 Gb/s signals enabled by a broadband photonic-chip-based radio-frequency spectrum analyser. We show simultaneous monitoring of group velocity dispersion, in-band optical signal-to-noise ratio and timing jitter from a single measurement.

We demonstrate residual dispersion and OSNR monitoring from 40Gb/s to 640Gb/s via slow-light enhanced optical THG in dispersion engineered 2D silicon photonic crystal waveguides.

We propose chip-based Tbaud processing for all-optical performance monitoring, switching and demultiplexing. We demonstrate the first transmitter optimization and receiver-end demultiplexing of 1.28 Tbit/s OOK signals. Both exploited Kerr nonlinearity in dispersion-engineered As 2 S 3 planar waveguide.

We report optical phase conjugation of wavelength multiplexed signals using a chalcogenide planar waveguide inserted along a transmission link. Distortion compensation of 3×40 Gb/s RZ-DPSK signals propagating through 225 km of standard single mode fiber is achieved.

We report the first demonstration of optical performance monitoring of ultrahigh bit-rate phase-encoded optical signals using a cm-scale, dispersion-engineered, highly nonlinear Chalcogenide planar waveguide.

We present the first demonstration of an optical sampling system, using the optical Kerr effect in a chip-scale device, enabling combined capability for femtosecond resolution and broadband signal wavelength tunability. A temporal resolution

We demonstrate simultaneous monitoring of the optical signal to noise ratio (OSNR) for wavelength-division multiplexed 40 Gb/s signals using the back-reflected Stokes wave from Stimulated Brillouin Scattering. A highly sensitive OSNR range of 5-25 dB is observed.

We report all-optical in-band OSNR monitoring at 160Gb/s via slow-light enhanced third harmonic generation in a 2D silicon photonic crystal waveguide, achieving better performance than quadratic methods.

We demonstrate broadband wavelength conversion of amplitude and phase-shift keyed signals at 40–160 Gb/s using the optical Kerr-effect in a photonic chip for the first time. This is enabled by a dispersion-shifted, highly nonlinear As2S3 waveguide.

We review the latest advances in dispersion-shifted Chalcogenide waveguides enabling highly nonlinear and low dispersion planar rib circuits of centimetre length. Its performance advantages for more broadband and higher speed nonlinear signal processing are shown.

We present the first demonstration of all optical wavelength conversion in chalcogenide glass fiber including system penalty measurements at 10 Gb/s. Our device is based on singlemode As2Se3 chalcogenide glass fiber which has the highest Kerr nonlinearity (n2) of any fiber to date for which either advanced all optical signal processing functions or system penalty measurements have been demonstrated. We achieve wavelength conversion via cross phase modulation over a 10 nm wavelength range near 1550 nm with 7 ps pulses at 2.1 W peak pump power in 1 meter of fiber, achieving only 1.4 dB excess system penalty. Analysis and comparison of the fundamental fiber parameters, including nonlinear coefficient, two-photon absorption coefficient and dispersion parameter with other nonlinear glasses shows that As2Se3 based devices show considerable promise for radically integrated nonlinear signal processing devices.

We review results on the recently developed dispersion-shifted, Chalcogenide waveguides demonstrating nonlinear signal processing on a compact monolithic platform with ultra-broadband capability and moderate launch powers of around 100 mW. Highlight results include broadband wavelength conversion of high-bit rate optical signals, time division multiplexing of 320 Gb/s signals and characterization of 320 Gb/s signals using a photonic chip based RF spectrum analyzer with terahertz bandwidth. The performance advantages stem from the waveguide's design for high nonlinearity and a near zero dispersion at the 1550 nm wavelength. These features are shown to enhance the efficiency of the nonlinear processes underpinning many all-optical signal processing functions.

A femtosecond pulse characterization technique is developed using frequency-resolved optical gating based on the two-photon absorption in an InP crystal. The technique provides direct visual monitoring of pulse frequency chirping in the time-spectral domain for femtosecond pulses with a pulse energy as low as 3.8 pJ. Pulse chirping and pedestal wings of 10-GHz optical fiber solitons are characterized experimentally for the first time by this technique.

We demonstrate broadband wavelength conversion of a 40 Gb/s return-to-zero signal using four-wave-mixing (FWM) in a dispersion engineered chalcogenide glass waveguide. The 6 cm long planar rib waveguide 2 mum wide was fabricated in a 0.87 mum thick film etched 350nm deep to correspond to a design where waveguide dispersion offsets the material leading to near-zero dispersion in the C-band and broadband phase matched FWM. The reduced dimensions also enhance the nonlinear coefficient to 9800 W(-1)km(-1) at 1550 nm enabling broadband conversion in a shorter device. In this work, we demonstrate 80 nm wavelength conversions with 1.65 dB of power penalty at a bit-error rate of 10(-9). Spectral measurements and simulations indicate extended broadband operation is possible.

Ultra-broad bandwidth (3.75 THz) RF spectrum analysis of femtosecond optical pulses is reported for the first time, enabled by the use of a short 6 cm length Chalcogenide waveguide designed for high nonlinearity and broadband low dispersion.

We demonstrate an all-optical RF spectrum analyser with >2.5THz bandwidth based on cross-phase modulation in a dispersion-engineered, nonlinear As2S3rib waveguide.

We demonstrate 40 GHz repetition sub-picosecond optical pulse generation from a LiNbO 3 Mach-Zehnder modulator by inserting it in a fiber-loop then using nonlinear pulse compression by dual-stage self-phase modulation. Application to 320 Gb/s signal generation is shown.

We demonstrate use of all optical mixing in a highly nonlinear fiber to achieve microwave photonic frequency measurement. The system is simple, compact, predictable and stable with potential applications in next generation radar warning receivers.

An all-optical photonic chip RF spectrum monitor with measurement bandwidth ≫2.5 THz is reported. Using a 16 cm length, highly nonlinear and broadband low dispersive As 2 S 3 planar rib waveguide, 320 Gb/s optical signals are characterized.

We demonstrate a photonic-chip-based optical sampling system with temporal resolution ≪500-fs, making use of four-wave mixing in a 7-cm chalcogenide planar waveguide. We use such a short, dispersion-shifted waveguide with ultrahigh nonlinearity (104/W/km) to monitor a 640-Gb/s datastream.

Optical pulse distortion due to third-order dispersion (TOD) in linear fiber transmission of 250-fs pulses at 5 GHz over 600 m is reduced by applying electrooptic phase modulation (EOPM) from a LiNbO/sub 3/ device. Initial propagation in dispersion-compensating fiber cancels the second-order dispersion of the fiber-link and also linearly chirps the pulses to a stretched width of 47 ps, which enables TOD compensation by the following 5-GHz EOPM. Good agreement between experimental and analytical results is shown. Comparable transmission improvement for the 250-fs pulses is achieved up to a maximum repetition rate of 6 GHz, limited by the RF amplifier bandwidth.

A review of the development and applications of compact highly nonlinear Chalcogenide waveguides for ultra-fast all-optical signal processing is presented. We demonstrate the extreme tapering of a highly nonlinear As2S3 fiber to further increase its nonlinearity by more than an order of magnitude thereby enabling time-division demultiplexing of a 160 Gb/s signal by four-wave mixing (FWM) with significantly lower optical powers. The tight mode confinement at such small fiber diameters also enhances the waveguiding dispersion to reduce the total dispersion for more broadband phase-matched FWM. We also present results on a low loss serpentine shaped rib waveguide of 22.5 cm length etched from a thin film of As2S3, that enables wavelength conversion of an 80 Gb/s signal by cross phase modulation, highlighting the potential for such high-speed signal processing to be performed in compact photonic chip circuits.

We experimentally demonstrate an all-optical technique for monitoring the radio-frequency (RF) spectrum of ultra-high bit-rate signals, with bandwidths exceeding 1 THz. This monitoring scheme exploits the ultra-fast response time of the optical Kerr nonlinear effect, such that the instantaneous intensity of the signal is translated to a phase modulation of a co-propagating probe, which can be measured as a frequency modulation on a standard optical spectrum analyzer, without the need for high-speed electronics. This scheme is applied to measure the optical RF spectrum of ultra-high bit-rate 160 and 320 Gb/s optical signals, and shows that impairments caused by either chromatic dispersion or amplitude modulation can be effectively monitored, thereby providing a useful diagnostic tool. The advantages of ultra-high bandwidth (up to terahertz), very fast response time and simple setup are highlighted.

A novel source of 2 ps optical pulses at 40 GHz repetition is demonstrated using a Mach-Zehnder modulator connected in a fiber-loop and compressing its output through self-phase modulation in highly nonlinear fibre and filtering.

Tapering As2Se3 fiber for enhancing its nonlinearity to 2500 W-1km-1, enables near penalty-free, wavelength conversion of a 40 Gb/s optical signal via cross-phase modulation in a shorter device length that reduces dispersion impact for more broadband operation.

Optical time-division demultiplexing a 160 Gb/s signal to 40 Gb/s tributaries by novel method of LiNbO3 amplitude modulator connected in a fiber-loop demonstrates lower bit-error rate power penalty than using a high performance electro-absorption modulator.

We demonstrate error free, low-penalty demultiplexing of a 640 Gbit/s OTDM signal to 10 Gbit/s using a 5 cm long chalcogenide planar waveguide chip. Our approach exploits four-wave mixing by the instantaneous nonlinear response of chalcogenide.

This research focuses on several aspects of chalcogenide all-optical processors. This study has chosen glasses in the Ge-As-Se system with the aim of optimising glass composition to obtain low loss, high nonlinearity and glass stability, whilst complementary efforts are focussed on the production, optimisation and application of chalcogenide waveguide devices to all-optical of high-speed telecommunication signals. Devices have been characterised in realistic telecommunications conditions with the eventual aim being to validate performance at rates up to 640 Gb/s.

The use of electro-optic phase modulation of dispersed optical pulses is investigated for compensating higher-order chromatic dispersion effects. The capability and limitations of the technique are described for compensating third- and fourth-order dispersion terms.

The large, ultra-fast Kerr nonlinearity and low nonlinear loss of chalcogenide glasses are attractive for chip based all-optical signal processing. We highlight successes including optical time demultiplexing at 160 Gb/s in As2S3 planar waveguides.

A sensitive optical signal-to-noise ratio (OSNR) monitor was implemented at 160Gb/s using the non-linear power transfer function (PTF) of an asymmetrical non-linear optical loop mirror (NOLM). The device is highly sensitive in the region 5-15dB OSNR.

A new optical time division demultiplexing technique is presented using a Mach-Zehdner modulator in a fiber loop mirror. Bit-error rate measurements show high- performance 4:1 demultiplexing of an 80 Gb/s optical signal to 20 Gb/s channels.

We present a novel principle for all-optical monitoring of optical signal-to-noise ratio (OSNR) that exploits the effect of in-band noise on stimulated Brillouin scattering (SBS). It shown for NRZ signals it can resolve OSNRs above 40 dB.

We experimentally investigate spectral phase modulation in a dynamic wavelength processor based on LCOS technology. Tunable dispersion compensation for agile optical networks is demonstrated at bitrates of 40 Gbit/s.

Chalcogenide glass based optical waveguides offer many attractive properties in all-optical signal processing because of the large Kerr nonlinearity (up to 420 × silica glass), the associated intrinsic response time of less than 100 fs and low two-photon absorption. These properties together with the convenience of a fiber format allow us to achieve all-optical signal processing at low peak power and in a very compact form. In this talk, a number of non-linear processing tasks will be demonstrated including all-optical regeneration, wavelength conversion and femtosecond pedestal-free pulse compression. In all-optical regeneration, we generate a near step-like power transfer function using only 2.8 m of fiber. Wavelength conversion is demonstrated over a range of 10 nm using 1 m of fiber with 7 ps pulses, peak power of 2.1 W, and 1.4 dB additional penalty. Finally, we will show efficient compression of low-power 6 ps pulses to 420 fs around 1550 nm in a compact all-fiber scheme. These applications show chalcogenide glass fibers are very promising candidate materials for nonlinear all-optic signal processing.

All-optical time-division demultiplexing of a 160 Gb/s signal into its tributary 10 Gb/s channels is demonstrated by four-wave mixing in just a 50 mm length As2S3waveguide exhibiting ultra-high optical Kerr nonlinearity over 2000 W−1km−1.

We establish design criteria for pump-probe devices in two photon absorbing materials and demonstrate low-power wavelength conversion over 10 nm in 1 m of single mode As/sub 2/Se/sub 3/ fiber through cross-phase modulation with only 1.4 dB system penalty at BER = 10/sup -9/.

We demonstrate error-free wavelength conversion near a = 1550nm at 10Gb/s based on cross-phase modulation in single mode As2Se3 chalcogenide glass fibre. We achieve 1.4dB excess system penalty with 2.1W average peak pump power in 1m of fibre over a 10nm range.

Compensation of higher-order fiber dispersion in addition to the group-velocity (second-order) dispersion (SOD) is important for 1.55 /spl mu/m optical time-division-multiplexed (OTDM) communication systems utilizing subpicosecond pulses to accommodate data-rates approaching Tbit/s. Third-order dispersion of 250 fs pulses propagating at /spl sim/5 GHz over fiber-link lengths of 600 m and 2.33 km was suppressed by applying electro-optic phase modulation after temporal stretching in a dispersion compensating fiber. Numerical simulations confirm that the technique can be equally effective at >10 GHz pulse repetition rates.

We introduce an all-optical, format transparent hash code generator and a hash comparator for data packets verification with low latency at high baudrate. The device is reconfigurable and able to generate hash codes based on arbitrary functions and perform the comparison directly in the optical domain. Hash codes are calculated with custom interferometric circuits implemented with a Fourier domain optical processor. A novel nonlinear scheme featuring multiple four-wave mixing processes in a single waveguide is implemented for simultaneous phase and amplitude comparison of the hash codes before and after transmission. We demonstrate the technique with single polarisation BPSK and QPSK signals up to a data rate of 80 Gb/s.

Compensation of nonlinear distortion of polarization-multiplexed (PolMux) signals in optical fiber is evaluated experimentally using all-optical signal pre-distortion and fiber loop phase-conjugation at the transmitter. An improved bit error rate is shown for high baud rate, 80 Gb/s RZ-DPSK PolMux signals before transmission in a 728 km long dispersion-managed fiber link employing a direct detection receiver. The partial compensation of nonlinear distortion for both single channel and 3 × 80 Gb/s WDM PolMux signals is observed, despite the impact from the inter-polarization nonlinearity and the associated polarization scattering. Evidence of the limited compensation of inter-polarization nonlinearity is shown.

We demonstrate all-optical wavelength conversion at 10 Gb/s for differential phase-shift keyed (DPSK) data signals in the C-band, based on four-wave mixing (FWM) in a silicon ring resonator. Error-free operation with a system penalty of ~ 4.1 dB at 10-9 BER is achieved.

We demonstrate on-chip all-optical pulse erasure based on four-wave mixing and cross-phase modulation in a dispersion engineered chalcogenide (As(2)S(3)) rib waveguide. We achieve an erasure efficiency of ~15 dB for picosecond pulses in good agreement with numerical simulations using the nonlinear Schrödinger equation. The combined effect of the high instantaneous optical nonlinearity (γ = 9900 (W km)(-1)) and small group-velocity dispersion (D = 29 ps/nm km), which reduces pulse walk-off, will enable all-optical pulse erasure for ultrafast signal processing.

We report the first demonstration of optical phase conjugation (OPC) transmission of phase encoded and wavelength-division multiplexed (WDM) signals by the Kerr effect in a planar structured waveguide. The phase conjugated electric field of the signal is produced by four wave mixing pumped by a CW laser during co-propagating with the signal in a highly nonlinear waveguide fabricated in As(2)S(3) glass. Experiments demonstrate the capability of the device to perform dispersion-free transmission through up to 225 km of standard single mode fiber for a 3 × 40 Gb/s WDM signal, with its channels encoded as return-to-zero differential phase shift keying and spaced either 100 or 200 GHz apart. This work represents an important milestone towards demonstrating advanced signal processing of high-speed and broadband optical signals in compact planar waveguides, with the potential for monolithic optical integration.