Benoit Filion

Wideband wavelength conversion of 16 Gbaud 16-QAM and 5 Gbaud 64-QAM signals in a semiconductor optical amplifier

We demonstrate wavelength conversion based on four-wave mixing in a semiconductor optical amplifier of signals with quadrature amplitude modulation (QAM). We first demonstrate wavelength conversion of 16 Gbaud 16-QAM signals over the entire C-band using two co-polarized pumps with low power penalty at the forward error correction threshold (FEC) for a wide range of input optical-signal-to-noise-ratio (OSNR). We also demonstrate for the first time wavelength conversion of 5 Gbaud 64-QAM signals in a semiconductor optical amplifier with bit-error rate below the FEC threshold over the entire C-band and investigate the dependence of the power penalty on input OSNR with a single pump configuration.

Dual phase-shift Bragg grating silicon photonic modulator operating up to 60 Gb/s

We demonstrate PAM-4 and OOK operation of a novel silicon photonic modulator. The modulator design is based on two phase-shifts in a Bragg Grating structure driven in a push pull configuration. Back-to-back PAM-4 modulation is demonstrated below the FEC threshold at up to 60 Gb/s. OOK modulation is also shown up to 55 Gb/s with MMSE equalization and up to 50 Gb/s without equalization. Eye diagrams and BER curves at different bit rates are provided for both PAM-4 and OOK modulations. To our knowledge, this structure is the fastest silicon photonic modulator based on Bragg gratings, reaching modulation speed comparable to the fastest Mach-Zehnder modulators and micro-ring modulators.

Segmented silicon MZM for PAM-8 transmissions at 114 Gb/s with binary signaling.

We experimentally demonstrate PAM-8 generation from binary electrical signals driving a silicon multi-electrode Mach-Zehnder modulator acting as an optical digital-to-analog converter. Measured BER in back-to-back configuration is used to evaluate signal quality. We demonstrate 38 GBd PAM-8 transmission below the forward error correction (FEC) threshold using minimum mean square error (MMSE) equalization. The results show that modulators with segmented phase shifters can be advantageously used to eliminate the need for high bandwidth electronic digital-to-analog converters in the generation of multilevel signals. These modulators, that can be designed and fabricated with standard CMOS compatible tools and processes, are of high interest for short range high-speed data links.

Fiber optic synchronisation architecture for high precision GPS applications

We propose a GPS-over-fiber solution that allows relative delay monitoring with millimetric precision and uplink transmission of down-converted GPS signal. Experimentations with directly modulated semiconductor devices show that it is suitable for high precision measurements.

Semiconductor Optical Amplifier-Based Wavelength Conversion of Nyquist-16QAM for Flex-Grid Optical Networks

We experimentally demonstrate semiconductor optical amplifier (SOA)-based wavelength conversion of 3 × 25 GBd Nyquist-16QAM signal for a flex-grid network. The conversion efficiency (CE) and power penalty of each of three channels during single pumped SOA wavelength conversion are studied with respect to three different channel spacings (or frequency grids). The BER performance of all converted channels fall below the FEC threshold of 3.8 × 10-3, even with a 50 GHz grid. The results show the tradeoff between channel spacing, CE, and BER power penalty. Closely packed channels, which clearly increase spectral efficiency, are also shown to decrease conversion power penalty, potentially counter balancing increased crosstalk levels. These results can be used to optimize routing and spectrum allocation strategy when SOA wavelength converter(s) are present in the optical link.

Digital Post-Compensation of Nonlinear Distortions in Wavelength Conversion Based on Four-Wave Mixing in a Semiconductor Optical Amplifier

We present a novel low-complexity digital filter-based backpropagation (DFBP) technique to compensate the nonlinear distortions induced by a wavelength converter based on four-wave mixing in a semiconductor optical amplifier. We first develop the DFBP based on a small-signal approximation and probe performance via numerical simulations. We also experimentally demonstrate that application of DFBP to wavelength conversion of 10 Gbaud 16-QAM and 5 Gbaud 64-QAM signals significantly improves the error-vector magnitude and the bit error rate when the wavelength converted signal is limited by the nonlinear distortions.

Extraction of semiconductor optical amplifier parameters for wavelength conversion modeling

We describe a simple characterization technique to experimentally extract the parameters necessary to accurately model four-wave mixing efficiency in semiconductor optical amplifier. Such characterization is important in the modeling and design of wavelength converters.

Compact silicon photonics-based multi laser module for sensing

A compact three-laser source for optical sensing is presented. It is based on a low-noise implementation of the Pound Drever-Hall method and comprises high-bandwidth optical phase-locked loops. The outputs from three semiconductor distributed feedback lasers, mounted on thermo-electric coolers (TEC), are coupled with micro-lenses into a silicon photonics (SiP) chip that performs beat note detection and several other functions. The chip comprises phase modulators, variable optical attenuators, multi-mode-interference couplers, variable ratio tap couplers, integrated photodiodes and optical fiber butt-couplers. Electrical connections between a metallized ceramic and the TECs, lasers and SiP chip are achieved by wirebonds. All these components stand within a 35 mm by 35 mm package which is interfaced with 90 electrical pins and two fiber pigtails. One pigtail carries the signals from a master and slave lasers, while another carries that from a second slave laser. The pins are soldered to a printed circuit board featuring a micro-processor that controls and monitors the system to ensure stable operation over fluctuating environmental conditions. This highly adaptable multi-laser source can address various sensing applications requiring the tracking of up to three narrow spectral features with a high bandwidth. It is used to sense a fiber-based ring resonator emulating a resonant fiber optics gyroscope. The master laser is locked to the resonator with a loop bandwidth greater than 1 MHz. The slave lasers are offset frequency locked to the master laser with loop bandwidths greater than 100 MHz. This high performance source is compact, automated, robust, and remains locked for days.