Parallelization of frequency domain quantum gates:manipulation and distribution of frequency-entangled photon pairs generated by a 21 GHz silicon microresonator

Harnessing the frequency dimension in integrated photonics offers key advantages in terms of scalability,noise resilience,parallelization,and compatibility with telecom multiplexing techniques.Integrated ring resonators have been used to generate frequency-entangled states through spontaneous four-wave mixing.However,state-of-the-art integrated resonators are limited by trade-offs among size,spectral separation,and efficient photon pair generation.We have developed silicon ring resonators with a footprint below 0.05 mm^(2)providing more than 70 frequency channels separated by 21 GHz.We exploit the narrow frequency separation to parallelize and independently control 34 single qubit-gates with a single set of three off-the-shelf electro-optic devices.We fully characterize 17 frequency-bin maximally entangled qubit pairs by performing quantum state tomography.We demonstrate for the first time,we believe,a fully connected five-user quantum network in the frequency domain.These results are a step towards a generation of quantum circuits implemented with scalable silicon photonics technology,for applications in quantum computing and secure communications.

Broadband supercontinuum generation in nitrogen-rich silicon nitride waveguides using a 300 mm industrial platform

We report supercontinuum generation in nitrogen-rich(N-rich)silicon nitride waveguides fabricated through back-end complementary-metal-oxide-semiconductor(CMOS)-compatible processes on a 300 mm platform.By pumping in the anomalous dispersion regime at a wavelength of 1200 nm,two-octave spanning spectra covering the visible and near-infrared ranges,including the O band,were obtained.Numerical calculations showed that the nonlinear index of N-rich silicon nitride is within the same order of magnitude as that of stoichiometric silicon nitride,despite the lower silicon content.N-rich silicon nitride then appears to be a promising candidate for nonlinear devices compatible with back-end CMOS processes.

GeSnOI mid-infrared laser technology

GeSn alloys are promising materials for CMOS-compatible mid-infrared lasers manufacturing.Indeed,Sn alloying and tensile strain can transform them into direct bandgap semiconductors.This growing laser technology however suffers from a number of limitations,such as poor optical confinement,lack of strain,thermal,and defects management,all of which are poorly discussed in the literature.Herein,a specific GeSn-on-insulator(GeSnOI)stack using stressor layers as dielectric optical claddings is demonstrated to be suitable for a monolithically integration of planar Group-IV semiconductor lasers on a versatile photonic platform for the near-and mid-infrared spectral range.Microdisk-shape resonators on mesa structures were fabricated from GeSnOI,after bonding a Ge_(0.9)Sn_(0.1) alloy layer grown on a Ge strain-relaxed-buffer,itself on a Si(001)substrate.The GeSnOI microdisk mesas exhibited significantly improved optical gain as compared to that of conventional suspended microdisk resonators formed from the as-grown layer.We further show enhanced vertical out-coupling of the disk whispering gallery mode in-plane radiation,with up to 30%vertical out-coupling efficiency.As a result,the GeSnOI approach can be a valuable asset in the development of silicon-based mid-infrared photonics that combine integrated sources in a photonic platform with complex lightwave engineering.

25 Gbps low-voltage hetero-structured silicongermanium waveguide pin photodetectors for monolithic on-chip nanophotonic architectures

Near-infrared germanium(Ge) photodetectors monolithically integrated on top of silicon-on-insulator substrates are universally regarded as key enablers towards chip-scale nanophotonics, with applications ranging from sensing and health monitoring to object recognition and optical communications. In this work, we report on the highdata-rate performance pin waveguide photodetectors made of a lateral hetero-structured silicon-Ge-silicon(Si-Ge-Si) junction operating under low reverse bias at 1.55 μm. The pin photodetector integration scheme considerably eases device manufacturing and is fully compatible with complementary metal-oxide-semiconductor technology. In particular, the hetero-structured Si-Ge-Si photodetectors show efficiency-bandwidth products of^9 GHz at-1 V and ~30 GHz at-3 V, with a leakage dark current as low as ~150 nA, allowing superior signal detection of high-speed data traffic. A bit-error rate of 10-9 is achieved for conventional 10 Gbps, 20 Gbps, and25 Gbps data rates, yielding optical power sensitivities of-13.85 dBm,-12.70 dBm, and-11.25 dBm, respectively. This demonstration opens up new horizons towards cost-effective Ge pin waveguide photodetectors that combine fast device operation at low voltages with standard semiconductor fabrication processes, as desired for reliable on-chip architectures in next-generation nanophotonics integrated circuits.