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We investigate high-speed optical sampling based on temporal lenticular lens. In our scheme, the sampling rate is enhanced by applying multi-wavelength time-interleaved processing. The effective number of bits ranges from 4.2 to 3.5 over the frequency range of 40 – 80 GHz.

We summarize our recent work on programmable generation of temporal waveforms. Our scheme is achieved with envelope programming of high-repetition-rate optical pulse trains through discrete Fourier transform (DFT) of modulated pulses.

We review our recent work on four-wave mixing Bragg scattering. Using two phase-locked pumps and phase control on the interacting waves, stable coherent addition of waves is achieved to enable versatile optical signal processing functions.

Stimulated Brillouin scattering has been adopted to regenerate an optical carrier from a single sideband signal. The carrier is applied for locking two frequency combs at the transmitter and receiver in a multi-wavelength communication system. Kramers-Kronig detection of 5 × 10 Gbaud QPSK/16-QAM channels is successfully demonstrated.

We propose a compact and high-speed I/Q modulator based on two germanium-on-silicon Franz-Keldysh electro-absorption modulators. We demonstrate a 4-QAM signal transmission and reconstruct the complex signal in a Kramers-Kronig receiver for future datacenter interconnect applications.

We demonstrate a new approach to generate microwave arbitrary waveforms by phase modulation and optical carrier processing based on gain-transparent SBS. Triangular waveforms at repetition rates of 5.64 and 7.87 GHz, and rectangular waveforms at repetition rates of 5.04 and 7.01 GHz are generated.

SVM has been successfully employed in BOTDA system to extract temperature information along fiber. It shows good robustness to a wide range of experiment parameters and its processing speed is 100 times faster than that of conventional Lorentzian fitting technique.

We show that the upper and lower sidebands of a multiband carrier-less amplitude phase (CAP) signal fulfil the condition of phase-conjugated twin waves. Through simulation and experiments, the reduction of intrachannel and interchannel nonlinear distortions are demonstrated. The optimum launched power for 200 km transmission is improved by 2 dB in a two-channel wavelength division multiplexing (WDM) system.

We demonstrate a technique to simultaneously generate multiple delayed signals through four-wave mixing (FWM) wavelength multicasting in a single-pump stimulated Brillouin scattering (SBS)-based slow-light system. The signal delay is achieved with an SBS pump while, at the same time, the delay is transferred to six other channels by three FWM pumps employed for wavelength multicasting. The delay performances of all output channels are analyzed. Relationship of the delay between the original signal and the multicast outputs is investigated and verified experimentally.

We study the absorption enhancement of graphene on silicon slot waveguides (SWs). The absorption of TE mode SW is 0.935 dB/µm at telecommunication band, higher than that of fundamental mode channel waveguides for both polarizations.

We report enhanced performances in fiber-optic parametric processing via backward Raman amplification, leading to increased gain, deferred saturation, suppressed crosstalk, reduced distortion in optical phase conjugation, and improved gain extinction ratio in phase-sensitive amplification.

We experimentally compare the extinction ratio enhancement of RZ-OOK signal using four-wave mixing in a silicon waveguide at 10 Gb/s and 40 Gb/s. The measured extinction ratio enhancement was 4.7 and 4.1 dB, respectively.

We propose and demonstrate a distributed strain sensing scheme using stimulated Brillouin scattering based slow light in an optical fiber. A measurement sensitivity of 0.056 ns/µe and a spatial resolution of 15 m are obtained.

We demonstrate a wideband clock recovery approach for NRZ-DPSK signals. Assisted by a 50-ps delay interferometer to generate a clock tone and a NPR-based format converter to enhance the tone in the optical domain, a SBS loop recovers the optical clocks of NRZ-DPSK signals with bit-rates ranging continuously from 7.5 to 15 Gb/s.

A novel method for temperature sensing is demonstrated by exploiting stimulated Brillouin scattering based slow light. The approach relies on temperature dependence of the Brillouin frequency shift in a fiber, and the consequent time delay of a probe pulse. Temperature sensing is achieved in a 100m SMF with high sensitivity.

We demonstrate the use of low-speed optoelectronic device to process high-speed optical signals with the use of time- and wavelength-interleaved pulses. Results show that the requirement on electronic bandwidth has been reduced using the wavelength division approach.

Bit-rate tunable demodulation for DPSK signals has been demonstrated in a relatively compact straight-line structure. The demodulation utilizes a tunable delay based on wavelength conversion and dispersion. Demodulations at 5 and 10 Gb/s have been successfully demonstrated.

Nondegenerate four-wave mixing is used in high- nonlinearity photonic crystal fiber with residual birefringence to achieve polarization-insensitive wideband wavelength conversion. The output power variation is below 0.2 dB and the conversion bandwidth is over 22 nm.

RZ-DPSK signals from 3 to 10 Gb/s are demodulated by a dual-pumped delay-asymmetric nonlinear loop mirror. The in-loop four-wave mixing conversion bandwidth is enhanced to over 35 nm for lower bit-rate demodulation.

We demonstrate simultaneous demultiplexing from 40 Gb/s OTDM to 4×10 Gb/s WDM channels by pump-modulated four-wave mixing with a time- and wavelength-interleaved pulsed source. An extinction ratio enhancement of ∼2.6 dB is achieved.

We propose a novel fiber-based in-line DPSK demodulator using an in-fiber Mach-Zehnder interferometer (MZI). The device is fabricated by controlling the splicing mismatch between a photonic crystal fiber and standard single mode fibers.

Different tunable delay schemes are demonstrated using nonlinear approaches for wavelength conversion in a 35-cm highly nonlinear bismuth-oxide fiber together with dispersion in a linearly chirped fiber grating. The compact setup offers a low-latency operation.

We demonstrate 40-GS/s all-optical wavelength division sampling using four-wave mixing in a dispersion-flattened photonic crystal fiber. Our 4x10-GHz time- and wavelength-interleaved sampling laser source is generated through multiwavelength cross-absorption modulation and optical dispersion management.

We demonstrate a compact tunable delay scheme with simultaneous signal regeneration using an electro-absorption modulator and a chirped fiber Bragg grating. Over 580-ps delay range is obtained with 2-dB improvement in the receiver sensitivity.

A fiber Bragg grating sensing system is demonstrated based on a continuous-wave Fourier domain mode locking fiber laser. Fiber Bragg grating interrogation is realized by mapping wavelength measurement to time measurement with an oscilloscope.

We demonstrate ASK-DPSK wavelength multicasting using four-wave mixing in a 32-cm bismuth oxide fiber. Six multicast channels each operating at 20 Gb/s are obtained at a 200 GHz spacing with a power penalty less than 3 dB.

We demonstrate a dispersion imbalanced loop mirror for interferometric noise suppression using a 32-cm highly nonlinear bismuth-oxide fiber. Improvement in the receiver sensitivity has been determined at different noise levels in a 10-Gb/s BER measurement.

We demonstrate a wavelength-retaining optical switch for DPSK signal using nonlinear polarization rotation in a SOA. The bit-rate transparent 1x2 optical router operates over 20 nm with a power penalty less than 3 dB.

Wavelength transparent DPSK demodulation is demonstrated using the delay-asymmetric nonlinear loop mirror (DANLM). The operation is explained by wavelength-dependent optical path difference between the two interfering branches.

We demonstrated slow light of 1 GHz and 10 GHz pulses using stimulated Brillouin scattering in a single mode fiber. The cw pump sources are spectrally broadened by phase modulation at different bit rates.

Widely tunable delay schemes are demonstrated using nonlinear phase modulation or four-wave mixing in a 32-cm bismuth oxide fiber followed by group velocity dispersion in a chirped fiber Bragg grating or a dispersion-compensated fiber.

Ultrafast all-optical logic gates are important for use in future high-speed communication systems. In particular, the exclusive-OR (XOR) gate is a commonly used device in optical signal processing like data encoding and high-speed pattern generation. Recently, much attention has been focused on DPSK signal owing to its higher immunity to optical nonlinearity during fiber transmission. An XOR gate has been previously demonstrated for RZ-DPSK signal using four-wave mixing in a SOA (Chan et al., 2004). In this paper, we demonstrate an XOR operation in a 35-cm highly nonlinear bismuth-oxide fiber (Bi-NLF). Owing to the extremely large nonlinear coefficient of ~1100 (W.km)-1 in the Bi-NLF, a very short fiber segment is sufficient to introduce significant four-wave mixing. The short fiber segment also minimizes the walk-off originated from group velocity mismatch, thus allowing a relatively wide-band (~12 nm) XOR operation. The passive, robust, and potentially low-cost fiber logic device offers another alternative to realize a compact XOR gate.

Wavelength converters play an important role in wavelength routed optical networks. Among these, an SOA-MZI based wavelength converter monolithically integrated with a tunable sampled-grating distributed Bragg reflector (SG-DBR) laser for amplitude shifted keying (ASK) signals. The integration of a tunable laser with the SOA-MZI enhances the reliability, the efficiency and the performance of the wavelength conversion process. In this work, we demonstrate 10-Gb/s DPSK wavelength conversion using a tunable SG-DBR laser-integrated SOA-MZI wavelength converter.

We demonstrate polarization-insensitive wavelength conversion of 10-Gb/s DPSK signal using a polarization-diversity scheme for four-wave mixing in 32-cm bismuth-oxide highly nonlinear fiber. The polarization dependence is

We demonstrate 10-Gb/s and 20-Gb/s DPSK and ASK-DPSK signal regeneration based on cross-phase modulation in a SOA. The amplitude noise is reduced and the receiver sensitivity is improved by 3 dB.

We demonstrate a mode-locked, multi-wavelength erbium-doped fiber laser with 25 GHz spacing and wavelength tunability operating at 1 GHz. Stable room-temperature operation is obtained by exploiting four-wave mixing in a length of highly nonlinear fiber.

Wide-band wavelength conversion is obtained in a 32-cm highly nonlinear bismuth oxide fiber using dual-pump four-wave mixing. The conversion for a 10-Gb/s NRZ-DPSK signal shows a power penalty below 4 dB over a 30-nm range.

A compact fiber-optic approach is demonstrated for an optically controlled variable delay for 10-Gb/s ASK and DPSK signals using four-wave mixing and group velocity dispersion. The measured power penalty is less than 4 dB.

Optically-controlled variable delay of up to 185 ps is obtained for 10-GHz pulses using four-wave mixing and group velocity dispersion in a compact fiber-optic setup. The pulse shape remains unchanged over the delay range.

We demonstrate all-optical amplitude-shift-keying to orthogonal code format conversion using cross-phase modulation in a dispersion-shifted fiber. A 2.5 Gb/s and a 10 Gb/s ASK signals are successfully converted to ASK/DPSK format.

A 15 channels /spl times/ 10GHz pulsed source has been generated with an extinction ratio >35 dB using an electro-absorption modulated semiconductor-optical-amplifier multi-wavelength ring laser. Interleaved waveband switching is achieved by electrically controlling the cavity birefringence.

We demonstrate a 10-GHz regeneratively mode-locked fiber laser using a birefringence loop mirror filter. The operating frequency is determined by the free-spectral-range of the filter and the component is extracted optically from the ring laser output