Christos Kouloumentas

Serial 100 Gb/s connectivity based on polymer photonics and InP-DHBT electronics.

We demonstrate the first integrated transmitter for serial 100 Gb/s NRZ-OOK modulation in datacom and telecom applications. The transmitter relies on the use of an electro-optic polymer modulator and the hybrid integration of an InP laser diode and InP-DHBT electronics with the polymer board. Evaluation is made at 80 and 100 Gb/s through eye-diagrams and BER measurements using a receiver module that integrates a pin-photodiode and an electrical 1:2 demultiplexer. Error-free performance is confirmed both at 80 and 100 Gb/s revealing the viability of the approach and the potential of the technology.

All-Optical RZ-to-NRZ Conversion of Advanced Modulated Signals

A generic scheme for return-to-zero (RZ) to nonreturn-to-zero (NRZ) format conversion of optical signals is analyzed. It relies on a simple delay interferometer with frequency periodicity twice as high as the input symbol rate and a subsequent optical band-pass filter. Simulation results at 40 Gbaud indicate the compatibility of the technique with a variety of advanced modulation formats. RZ-to-NRZ conversion of 40 Gb/s differential phase shift keying signals is experimentally demonstrated with 1.5 dB power penalty compared to the back-to-back measurement.

Four-Channel All-Fiber Dispersion-Managed 2R Regenerator

We experimentally investigate a dispersion-managed four-channel 2R regenerator that relies on self-phase modulation-induced spectral broadening and offset filtering at four shifted wavelengths. The device consists of several alternating sections of dispersion-compensating fibers and single-mode fibers. Due to this arrangement and the use of low duty-cycle return-to-zero pulses, nonlinear interchannel effects are sufficiently mitigated resulting in almost no additional degradation compared to the single-channel case.

DPSK Regeneration at 40 Gb/s and Beyond Using a Fiber-Sagnac Interferometer

We analyze the experimental demonstration of a phase-incoherent regeneration scheme for differential phase-shift keying signals at 40 Gb/s. The scheme is based on decoding of the input signal by a 1-bit delay interferometer and subsequent optical remodulation using a fiber-Sagnac interferometer. Power penalty improvement up to 3 dB is reported for phase, amplitude, and amplified spontaneous emission noise loaded signals. Simulation results are in agreement with the experimental findings, and reveal the capability of extending the method at ultrahigh data rates.

Multi-100 GbE and 400 GbE Interfaces for Intra-Data Center Networks Based on Arrayed Transceivers With Serial 100 Gb/s Operation

We demonstrate a 2 × 100 Gb/s transmitter and a 4 × 100 Gb/s receiver as the key components for multi-100-GbE and 400-GbE optical interfaces in future intradata center networks. Compared to other approaches, the two devices can provide significant advantages in terms of number of components, simplicity, footprint, and cost, as they are capable of serial operation with nonreturn-to-zero on-off keying format directly at 100 Gb/s. The transmitter is based on the monolithic integration of a multimode interference coupler with two Mach-Zehnder modulators on an electro-optic polymer chip, and the hybrid integration of this chip with an InP laser diode and two multiplexing and driving circuits. The receiver on the other hand is based on the hybrid integration of a quad array of InP photodiodes with two demultiplexing circuits. Combining the two devices, we evaluate their transmission performance over standard single-mode fibers without dispersion compensation and achieve a BER of 10-10 after 1000 m and a BER below 10-8 after 1625 m at 2 × 80 Gb/s, as well as a BER below 10-7 after 1000 m at 2 × 100 Gb/s. Future plans including the development of tunable 100 GbE interfaces for optical circuit-switched domains inside data center networks are also discussed.

\(2 \times 100\) -Gb/s NRZ-OOK Integrated Transmitter for Intradata Center Connectivity

We demonstrate an integrated transmitter that can generate two 100-Gb/s optical channels with simple nonreturn-to-zero-ON-OFF keying format. The transmitter is based on the combination of an ultrafast electro-optic polymer platform for the photonic integration and the optical modulation with ultrafast InP-double heterojunction bipolar transistor electronics for the multiplexing and the amplification of the 100-Gb/s driving signals. Through error-free transmission of 2 × 80-Gb/s signals over 1 km of SMF and transmission of 2 × 100-Gb/s signals over 500 m of single-mode fiber with error performance way below the forward error correction limit, we reveal the potential of the approach for parallel 100-GbE optical interfaces in small footprint transceivers for intradata center networks.

Microring-Resonator-Assisted, All-Optical Wavelength Conversion Using a Single SOA and a Second-Order Si

We present the first microring-resonator-assisted wavelength converter employing a semiconductor optical amplifier and a tunable, Si3N4-SiO2 microring-resonator-reconfigurable optical add-drop multiplexer. We demonstrate inverted, noninverted, and wavelength-division-multiplexing-enabled wavelength conversion with low power penalties.

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We present the RAWC, the first Ring Resonator Assisted Wavelength Converter employing a SOA and a tunable, Si<inf>3</inf>N<inf>4</inf>-SiO<inf>2</inf> micro-ring resonator ROADM. We demonstrate inverted, non-inverted and WDM-enabled wavelength conversion with low power penalties.

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We develop a method for the repetition rate multiplication by a factor of 2 n of pseudorandom bit sequences (PRBSs). It makes recursive use of an optical or-gate in feedback and ensures that the complexity of the resulting circuit is independent of the multiplication factor or the PRBS order to be rate multiplied. We employ an all-optical circuit comprising of two nonlinear fiber Sagnac interferometers and show error-free quadrupling of 12.5-Gb/s PRBSs to 50 Gb/s.

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A network concept is introduced that exploits transparent optical grooming of traffic between an access network and a metro core ring network. This network is enabled by an optical router that allows bufferless aggregation of metro network traffic into higher-capacity data streams for core network transmission. A key functionality of the router is WDM to time-division multiplexing (TDM) transmultiplexing.