Modelling of an intersubband quantum confined Stark effect in Ge quantum wells for mid-infrared photonics

: In this work we theoretically investigate quantum confined Stark effect of intersubband transitions in asymmetric Ge/SiGe quantum wells for intensity modulation in the mid-infrared. Our calculations show that extinction ratios up to 1 dB and modulation speeds of several tens of GHz could be obtained in 100 µm long waveguides

Low-Power consumption Franz-Keldysh effect plasmonic modulator

In this paper we report on a low energy consumption CMOS-compatible plasmonic modulator based on Franz-Keldysh effect in germanium on silicon. We performed integrated electro-optical simulations in order to optimize the main characteristics of the modulator. A 3.3 dB extinction ratio for a 30 µm long modulator is demonstrated under 3 V bias voltage at an operation wavelength of 1647 nm. The estimated energy consumption is as low as 20 fJ/bit

QPSK Modulation in the O-Band Using a Single Dual-Drive Mach Zehnder Silicon Modulator

[EN] Keeping up with bandwidth requirements in next generation short- and long-reach optical communication systems will require migrating from simple modulation formats such as on-off keying to more advanced formats such as quaternary phase-shift keying (QPSK). In this paper, we report the first demonstration of QPSK signal generation in the O-band using a silicon dual-drive Mach-Zehnder modulator (DD-MZM). The performance of the silicon DD-MZM is assessed at 20 Gb/s and compared against a similar DD-MZM based on LiNbO3, showing a limited implementation power penalty of only 1.5 dB.This work was supported in part by the European project Plat4m (FP7-2012-318178); European project Cosmicc (H2020-ICT-27-2015- 688516); French Industry Ministry Nano2017 program.Pérez-Galacho, D.; Bramerie, L.; Baudot, C.; Chaibi, M.; Messaoudène, S.; Vulliet, N.; Vivien, L.... (2018). QPSK Modulation in the O-Band Using a Single Dual-Drive Mach Zehnder Silicon Modulator. Journal of Lightwave Technology. 36(18):3935-3940. https://doi.org/10.1109/JLT.2018.2851370S39353940361

Silicon-on-insulator polarization controller with relaxed fabrication tolerances

Polarization control is essential in applications ranging from optical communications to interferometric sensors. The implementation of in- tegrated polarization controllers is challenging as they require polariza- tion rotating waveguides with stringent fabrication tolerances. Here, we present a fully integrated polarization controller scheme that signi cantly relaxes the requirements on the rotating waveguides, alleviating fabri- cation tolerances. We analytically establish a technology-independent, easily measurable tolerance condition for the rotating waveguides. Po- larization control in the presence of waveguide width errors of 25% is shown through full vectorial simulation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Long-wave infrared integrated resonators in the 7.5-9 mu m wavelength range

We present broadband on-chip resonators based on SiGe graded-index waveguides operating in the long-wave infrared spectral range from 7.5 to 9.0 mu m wavelength range. A quality factor up to 10(5) has been measured, while an intrinsic quality factor of 1.13 x 10(5) has been extracted from the measurements. Thermal tuning of the phase in the micro-ring has been used to overcome the limitation of the experimental setup in terms of spectral resolution. These results pave the way toward the development of integrated frequency comb operating in the long-wave infrared range

Broadband Fourier-transform silicon nitride spectrometer with wide-area multiaperture input

4 pags., 5 figs.Integrated microspectrometers implemented in silicon photonic chips have gathered a great interest for diverse applications such as biological analysis, environmental monitoring, and remote sensing. These applications often demand high spectral resolution, broad operational bandwidth, and large optical throughput. Spatial heterodyne Fourier-transform (SHFT) spectrometers have been proposed to overcome the limited optical throughput of dispersive and speckle-based on-chip spectrometers. However, state-of-the-art SHFT spectrometers in near-infrared achieve large optical throughput only within a narrow operational bandwidth. Here we demonstrate for the first time, to the best of our knowledge, a broadband silicon nitride SHFT spectrometer with the largest light collecting multiaperture input (320 × 410 µm) ever implemented in an SHFT on-chip spectrometer. The device was fabricated using 248 nm deep-ultraviolet lithography, exhibiting over 13 dB of optical throughput improvement compared to a single-aperture device. The measured resolution varies between 29 and 49 pm within the 1260-1600 nm wavelength range.Spanish Ministry of Science and Innovation (MICINN) (RED2018-102768-T, RTI2018-097957-B-C33, TEC2015-71127-C2-1-R (FPI Scholarship BES-2016-077798)); Community of Madrid-FEDER funds (S2018/NMT-4326); Horizon 2020 Research and Innovation Program (Marie Sklodowska-Curie 734331); H2020 European Research Council (ERC POPSTAR 647342); European Commission (H2020- ICT-26127-2017 COSMICC 688516); French Industry Ministry (Nano2022 project under IPCEI program); Agence Nationale de la Recherche (ANR-MIRSPEC-17-CE09-004

Silicon CMOS photonics platform for enabling high-speed DQPSK transceivers

In this work we review the results obtained under the framework of FP7-HELIOS project for integrated DQPSK transceivers in silicon photonics. A differential DQPSK receiver with balanced zero biased Germanium photodiodes has been demonstrated at 10Gbit/s with an error floor around 10(-15). Furthermore, DPSK modulation up to 10Gbit/s with a bit error rate below 10(-9) is also demonstrated using a silicon push-pull operated dual-drive Mach-Zehnder modulator (MZM) based on carrier depletion. The results indicate the potential of the silicon CMOS photonics platform for boosting next-generation optical networks based on advanced modulation formats

Silicon optical modulators

Optical technology is poised to revolutionize short-reach interconnects. The leading candidate technology is silicon photonics, and the workhorse of such an interconnect is the optical modulator. Modulators have been improved dramatically in recent years, with a notable increase in bandwidth from the megahertz to the multigigahertz regime in just over half a decade. However, the demands of optical interconnects are significant, and many questions remain unanswered as to whether silicon can meet the required performance metrics. Minimizing metrics such as the device footprint and energy requirement per bit, while also maximizing bandwidth and modulation depth, is non-trivial. All of this must be achieved within an acceptable thermal tolerance and optical spectral width using CMOS-compatible fabrication processes. This Review discusses the techniques that have been (and will continue to be) used to implement silicon optical modulators, as well as providing an outlook for these devices and the candidate solutions of the future