Gerrit Fiol

A low insertion loss and low V π InP IQ modulator for advanced modulation formats

We demonstrate a high performance chip-on-carrier IQ modulator based on InP MQW technology. The device achieved a 3-dB bandwidth of 40 GHz, a Vπ of 2.2 V and an insertion loss of <;6.5 dB over the C-band.

Segmented Optical Transmitter Comprising a CMOS Driver Array and an InP IQ-MZM for Advanced Modulation Formats

Segmented Mach–Zehnder modulators are promising solutions to generate complex modulation schemes in the migration towards optical links with a higher-spectral efficiency. We present an optical transmitter comprising a segmented-electrode InP IQ-MZM, capable of multilevel optical signal generation (5-bit per I/Q arm) by employing direct digital drive from integrated, low-power (1W) CMOS binary drivers. We discuss the advantages and design tradeoffs of the segmented driver structure and the implementation in a 40 nm CMOS technology. Multilevel operation with combined phase and amplitude modulation is demonstrated experimentally on a single MZM of the device for 2-ASK-2PSK and 4-ASK-2-PSK, showing potential for respectively 16-QAM and 64-QAM modulation in future assemblies.

DAC-Free Ultralow-Power Dual-Polarization 64-QAM Transmission at 32 GBd With Hybrid InP IQ SEMZM and BiCMOS Drivers Module

A hybrid transmitter module comprising a 15-segment InP IQ segmented Mach–Zehnder modulator and two 0.13 μm BiCMOS SiGe:C drivers with integrated 4-bit DAC functionality is described. The high-resolution prototype allows a wide range of modulation formats and, for the first time, ultralow-power dual-polarization (DP) 64-QAM signal generation at record speed of 32 GBd without the usage of external DACs is demonstrated. The DP 64-QAM signal is transmitted error free over 80 km of SSMF with 7.8 pJ/bit/polarization energy consumption. Post-FEC BER results are presented, with more than 226 bits decoded without errors after four decoding iterations. The package footprint is 28 mm × 76 mm. These results evidence the advantage of the proposed arrangement for the next generation low-power high-speed optical transceivers.

DAC-Less 32-GBd PDM-256-QAM Using Low-Power InP IQ Segmented MZM

We demonstrate DAC-less generation and transmission of 256-quadrature amplitude modulation signals at a symbol rate of 32 GBd using an indium phosphide segmented Mach–Zehnder modulator with 15 active sections and dedicated BiCMOS driver arrays. The linear quantization characteristic of the segmented modulator with 4-bit resolution allows the generation of spectrally efficient modulation formats without any transmitter side signal processing. The chip power consumption of 1.64 W translates into the record-low energy per bit of 6.4 pJ/b. Back-to-back performance is evaluated and two different low-density parity check codes enable error-free transmission over 80 and 120 km with a net data rate of 320 and 240 Gb/s, respectively.

High-Speed Ultralow-Power Hybrid Optical Transmitter Module With InP I/Q-SEMZM and BiCMOS Drivers With 4-b Integrated DAC

A hybrid optical transmitter module comprising a 15-segment InP in-phase/quadrature-phase segmented Mach-Zehnder modulator and two SiGe:C BiCMOS drivers featuring integrated 4-b digital-to-analog converter functionality is described. The drivers, fabricated in the 0.13-μm process of IHP, deliver a differential output voltage of 2.5 Vpp across all the 15 segments while dissipating less than 1 W of power each, at the maximum. Clear electrical eye diagrams up to 40-Gb/s from every output are reported. The module allows a wide range of modulation formats, among which up to eight-pulse amplitude modulation and polarization-division-multiplexed (PDM) 64-quadrature amplitude modulation (QAM) back-to-back error-free electro-optical transmission at a record speed of 32 GBd are demonstrated. The 32-GBd PDM 64-QAM signal was transmitted error-free over 80 km of standard single-mode fiber, featuring 7.8-pJ/b energy consumption. The devised hybrid arrangement proves the suitability of SiGe HBT drivers for achieving higher speeds over their CMOS counterparts, with comparable low power dissipation, for advanced optical transceivers.

Engineered Transfer Function InP Mach–Zehnder Modulator for Bandwidth Enhancement and Nyquist Shaping

A segmented modulator which shapes the optical spectrum of the modulated signal by resonating sections is presented. The modulator enhances the bandwidth of the slow driving electronics at its input. 1.5-fold 3-dB bandwidth enhancement for the driver-modulator system is shown. Error-free transmission of 23 Gb/s OOK is achieved with driving electronics of 7.5 GHz bandwidth only. The spectrum narrowing capability of the resonant modulator is also discussed. 40 Gb/s eye and error-free transmission over 9 km SSFM are measured with a reduced occupied bandwidth compared to a standard LiNbO3 modulator. Advantage over standard modulators is therefore demonstrated.