Carl Paquet

Experimental study of 112 Gb/s short reach transmission employing PAM formats and SiP intensity modulator at 1.3 μm

We present a Silicon Photonic (SiP) intensity modulator operating at 1.3 μm with pulse amplitude modulation formats for short reach transmission employing a digital to analog converter for the RF signal generator, enabling pulse shaping and precompensation of the transmitters frequency response. Details of the SiP Mach-Zehnder interfometer are presented. We study the system performance at various bit rates, PAM orders and propagation distances. To the best of our knowledge, we report the first demonstration of a 112 Gb/s transmission over 10 km of SMF fiber operating below pre-FEC BER threshold of 3.8 × 10(-3) employing PAM-8 at 37.4 Gbaud using a fully packaged SiP modulator. An analytical model for the Q-factor metric applicable for multilevel PAM-N signaling is derived and accurately experimentally verified in the case of Gaussian noise limited detection. System performance is experimentally investigated and it is demonstrated that PAM order selection can be optimally chosen as a function of the desired throughput. We demonstrate the ability of the proposed transmitter to exhibit software-defined transmission for short reach applications by selecting PAM order, symbol rate and pulse shape.

Experimental Parametric Study of a Silicon Photonic Modulator Enabled 112-Gb/s PAM Transmission System With a DAC and ADC

A packaged silicon photonic traveling wave Mach-Zehnder modulator operating at 1310 nm is presented and studied. The modulator is a series push-pull device and requires a bias applied to the common n-doped region. Effects of varying the bias voltage on the modulators Vπ bandwidth, and on chip-insertion loss are studied, and its impact on transmission performance are experimentally investigated for PAM-4 and PAM-8 formats at a throughput of 112 Gb/s, over varying distances of 0, 2, 10, and 20 km. Residual chromatic dispersion is shown to have no impact on performance up to 20 km. The PAM RF driving waveform is generated by an 8-bit digital-to-analog converter, while direct detection is done with a PIN+TIA followed by an 8-bit analog-to-digital converter. This IM/DD system utilizes digital signal processing with transmitter spectral compensation and receiver residual equalization. The performance impact for a varying number of transmitter precompensation taps and receiver equalization taps is studied, which has a direct impact on the transceivers power consumption. Using PAM-4, a BER below the FEC limit is obtained for either combinations of (transmitter, receiver) tap lengths: (19,19), (7,27), or (35,7), allowing flexibility in power consumption distribution.

Transmission of 107-Gb/s DQPSK over Verizon 504-km Commercial LambdaXtreme® Transport System

A 107-Gb/s field trial was conducted on a traffic carrying long-haul LambdaXtreme® transport platform over an active 504-km Verizon route in Florida thus proving upgradeability to 100 G of the Alcatel-Lucent 50-GHz spaced ULH DWDM system.

Recent progress on FBG-based tunable dispersion compensators for 40 Gb/s applications

The optical performance of state-of-the-art FBG-based tunable dispersion compensators is given in view of the recent advances. Results are given for a 33-channel device with 80 GHz bandwidth, 200 GHz channel spacing and tunable from -400 to +400 ps/nm, and for a 51-channel device with 40 GHz bandwidth, 100 GHz channel spacing and tunable from -600 to +600 ps/nm.

Analytical and experimental performance evaluation of an integrated Si-photonic balanced coherent receiver in a colorless scenario

We study analytically and experimentally the performance limits of a Si-photonic (SiP) balanced coherent receiver (CRx) co-packaged with transimpedance amplifiers (TIAs) in a colorless WDM scheme. Firstly, the CRx architecture is depicted and characterization results are presented. Secondly, an analytical expression for the signal-to-noise ratio (SNR) at the CRx output is rigorously developed and various noise sources in the context of colorless reception are outlined. Thirdly, we study experimentally the system-level CRx performance in colorless reception of 16 × 112 Gbps PDM-QPSK WDM channels. Using a 15.5 dBm local oscillator (LO) power, error free transmissions over 4800 and 4160 km at received powers of -3 and -21 dBm per channel, respectively, were achieved in a fully colorless and preamplifierless reception. Next, a set of measurements on one of the center WDM channels is performed where the LO power, received signal power, distance, and number of channels presented to the CRx are swept to evaluate the performance limits of colorless reception. Results reveal that the LO beating with optical noise incoming with the signal is a dominant noise source regardless of received signal power. In the high received signal power regime (~0 dBm/channel), the self-beat noise from out-of-band (OOB) channels is an additional major noise source especially for small LO-to-signal power ratio, short reach and large number of OOB channels. For example, at a received signal power of 0 dBm/channel after 1600 km transmission, the SNR difference between the fully filtered and colorless scenarios, where 1 and 16 channels are passed to the CRx respectively, grows from 0.5 to 3.3 dB as the LO power changes from 12 to 0 dBm. For low received power (~-12 dBm/channel), the effect of OOB channels becomes minor while the receiver shot and thermal noises become more significant. We identify the common mode rejection ratio (CMRR) and sensitivity as the two important CRx specifications that impact the performance at high and low received signal power regimes, respectively. Finally, an excellent match between experimental and analytical SNRs is proven after the derived SNR model is fitted to the experimental data in a least-squares sense. The model is then used to predict that the CRx can operate colorlessly for a fully populated WDM spectrum with 80 channels provided that the LO-to-signal power ratio is properly set.

Ultra-compact coherent receiver based on hybrid integration on silicon

A coherent receiver based on silicon photonics is presented. Its performance is confirmed by single-channel and WDM transmission tests with PM-QPSK modulation at 28 Gbaud up to 4800 km. The packaged core is very compact with dimensions of 6 mm × 8 mm.

107 Gb/s PAM-4 transmission over 10 km using a SiP series push-pull modulator at 1310 nm

Using a series push-pull SiP modulator at 1310 nm, transmission using PAM-4 at 53.5 GBaud over 10 km of SMF-28 fiber is realized at a BER of 3.6×1 0^-3.

400-G Single Carrier 500-km Transmission With an InP Dual Polarization IQ Modulator

In this letter, we demonstrate experimentally 400-G transmission over 500 km using an InP-based dual-polarization IQ modulator on a single wavelength. The results show that a 56-Gbaud polarization division multiplexed (PDM)-16-quadratic-amplitude modulation (QAM) modulated signal can be transmitted over 500 km at a bit error rate (BER) below the hard decision forward error correcting threshold of 3.8 ×10-3. A 43-Gbaud PDM-64-QAM modulated signal can be transmitted over 320 km with a BER below the soft decision forward error correcting threshold of 2×10-2.

107-Gb/s Transmission over 700 km and One Intermediate ROADM using LambdaXtreme® Transport System

We demonstrate 107-Gb/s single-channel transmission over the commercial all-Raman LambdaXtreme® transport system. Both RZ-DQPSK and NRZ-DQPSK formats were transmitted over 700 km with one reconfigurable optical add drop multiplexer (ROADM) node at 500 km.

Optical Tunable Dispersion Compensators based on Thermally Tuned Fiber Bragg Gratings

Fiber Bragg gratings are well positioned to respond to the growing need for more stringent control of dispersion compensation. Thermal tuning has proven to be an effective technique for achieving this goal.