The growth of integrated photonics has driven the need for efficient, high-bandwidth electrical-to-optical (EO) signal conversion over a broad range of frequencies (MHz–THz), together with efficient, high bandwidth photodetection. Efficient signal conversion is needed for applications including fiber/wireless telecom, data centers, sensing/imaging, metrology/spectroscopy, autonomous vehicle platforms, etc., as well as cryogenic supercomputing/quantum computing. Diverse applications require the ability to function over a wide range of environmental conditions (e.g., temperatures from <4 to >400 K). Active photonic device footprints are being scaled toward nanoscopic dimensions for size compatibility with electronic elements. Nanophotonic devices increase optical and RF field confinement via small feature sizes, increasing field intensities by many orders of magnitude, enabling high-performance Pockels effect materials to be ultimately utilized to their maximum potential (e.g., in-device voltage-length performance ≤0.005 V mm). Organic materials have recently exhibited significant improvements in performance driven by theory-guided design, with realized macroscopic electro-optic activity (r33) exceeding 1000 pm/V at telecom wavelengths. Hybrid organic/semiconductor nanophotonic integration has propelled the development of new organic synthesis, processing, and design methodologies to capture this high performance and has improved understanding of the spatial distribution of the order of poled materials under confinement and the effects of metal/semiconductor-organic interfaces on device performance. Covalent coupling, whether from in situ crosslinking or sequential synthesis, also provides a thermally and photochemically stable alternative to thermoplastic EO polymers. The alternative processing techniques will reduce the attenuation of r33 values observed in silicon organic hybrid and plasmonic organic hybrid devices arising from chromophore-electrode electrostatic interactions and material conductance at poling temperatures. The focus of this perspective is on materials, with an emphasis on the need to consider the interrelationship between hybrid device architectures and materials.

Plasmonic modulators have been assessed for operation up to 200 GBaud in a turbulent 53 km free-space-optical link. They are shown to withstand space radiation and large temperature ranges making them ideal for space applications.

Resonant modulators encode electrical data onto wavelength-multiplexed optical carriers. Today, silicon microring modulators are perceived as promising to implement such links; however, they provide limited bandwidth and need thermal stabilization systems. Here we present plasmonic micro-racetrack modulators as a potential successor of silicon microrings: they are equally compact and compatible with complementary-metal–oxide–semiconductor-level driving voltages, but offer electro-optical bandwidths of 176 GHz, a 28 times improved stability against operating temperature changes and no self-heating effects. The temperature-resistant organic electro-optic material enables operation at 85 °C device temperature. We show intensity-modulated transmission of up to 408 Gbps at 12.3 femtojoules per bit with a single resonant modulator. Plasmonic micro-racetrack modulators offer a solution to encode high data rates (for example, the 1.6 Tbps envisioned by next-generation communications links) at a small footprint, with low power consumption and marginal, if no, temperature control.

A novel vertical incidence metamaterial enhanced graphene photodetector featuring a 200 nm spectral window and a setup limited bandwidth of 500 GHz is demonstrated. The photodetector has been tested for data transmission in an all plasmonic EOE-link offering unprecedented 250 GHz bandwidth.

A high-speed and compact plasmonic organic racetrack modulator is shown to be orders of magnitude more robust against operating condition changes compared to resonant modulators based on the plasma dispersion effect while maintaining thermal tunability. Stable operation at 80°C is shown with no degradation. © 2022 Optica

The first transparent Optical-subTHz-Optical link providing record-high line-rates of 240 and 190 Gbit/s over distances from 5 to 115 m was recently demonstrated. The link has been based on a direct data-conversion from optical to subTHz using a > 500 GHz plasmonic Mach-Zehnder modulator. We discuss the potential of plasmonic devices in subTHz wireless links to efficiently bridge optical fiber networks.

We report on coherent transmission of beyond 100 GBd signaling based on plasmonic technology. Using dual-drive plasmonic-organic-hybrid I/Q modulator on silicon photonics platform, we demonstrate the successful transmission of 160-GBaud QPSK and 140-GBaud 16QAM modulations.

We summarize our experimental exploration of the capabilities of an ultrabroad-bandwidth plasmonic Mach-Zehnder modulator (MZM), in an intensity modulation and direct detection (IM/DD) system for short-reach optical transmission up to 10 km. We study modulation, transmission, and reception of ultrahigh-symbol-rate (up to 304 GBd) multi-level optical signals with two different signaling schemes: pulse amplitude modulation (PAM), with up to 8 amplitude levels and partial-response-encoded binary (polybinary) modulation with memory length up to 4. By mapping the performance to a concatenated soft-decision (SD) and hard-decision (HD) forward error correction (FEC) coding scheme, a net bitrate of 363.4 Gbit/s is possible with PAM-8 signaling and 279.0 Gbit/s with tetrabinary (polybinary) signaling after 10 km standard single-mode fiber transmission. Considering an HD-only coding scheme, a net bitrate of 318.0 Gbit/s is possible with PAM-6 and 277.1 Gbit/s with tetrabinary.

A transparent Optical-subTHz-Optical link providing record-high single line rates of 240 Gbit/s and 192 Gbit/s on a single optical carrier over distances from 5 to 115 m is demonstrated.Besides a direct mapping of the optical to a 230 GHz subTHz-carrier frequency by means of a uni-traveling carrier (UTC) photodiode, we demonstrate direct conversion of data from the subTHz domain back to the optical domain by a plasmonic modulator.It is shown that the subTHz-to-optical upconversion can even be performed at good quality without any electrical amplifiers.Finally, at the receiver, the local oscillator is employed to directly map the optical signal back to the electrical baseband within a coherent receiver.

Plasmonic PICs offer compact high-speed photonic and plasmonic components, enabling a new generation of scalable photonic system solutions. We explain the underlying technology, highlight key applications, review technology demonstrations, and discuss future opportunities.

We demonstrate an energy-efficient, 100-GHz plasmonic modulator operating at 4 K for beyond 128 GBd data modulation with ultra-low driving voltage of 0.1 V. High-speed components at cryogenic temperature are essential building blocks for scalable next-generation quantum computing systems.

OOK line rates of 220 Gbit/s and 408 Gbit/s 8PAM and transmission over 100 m are demonstrated with a resonant plasmonic racetrack modulator. The device requires low 0.6 Vp driver voltages, offers a bandwidth >110 GHz and on-chip losses of 1.0 dB.

We employ an ultrabroad-bandwidth plasmonic Mach-Zehnder modulator to demonstrate 10-km IM/DD transmission at a symbol rate of 304-GBd (AIR 293.3-Gbit/s, net 270.0-Gbit/s) realized with a poly-binary modulation scheme, and a line rate of 432-Gbit/s (AIR 383.6-Gbit/s, net 350.4-Gbit/s) using PAM-8.

We present the ultra-high bandwidth plasmonics platform that enables efficient electro-optic modulation at micrometer scale. Applications in optical communications are discussed.

We present reliability studies of plasmonic-organic-hybrid modulators for high-speed optical communications. By exclusion of oxygen and water, demanding thermal environments and high optical power levels can be tolerated.

We demonstrate low-loss fiber-to-chip coupling via a-Si grating couplers on top of SiN waveguides for C-band TE light. The suggested simple scheme is fabrication tolerant and offers a path towards coupling efficiencies above -1 dB.

The first transparent Optical-THz-Optical link providing record-high line-rates up to 240 and 190 Gbit/s over distances from 5 to 115m is demonstrated. The link is based on direct data-conversion from optical to sub-THz and vice-versa.

A novel plasmonic graphene-organic hybrid phase modulator featuring the short length and fast speed of plasmonics (10µm length, bandwidths in excess of 70GHz) but benefitting from the lower losses of graphene (on-chip insertion losses of 4.5dB) is introduced. Successful operation at 100 Gbit/s is shown.

Low power broadband plasmonic silicon-photonic racetrack modulators are introduced. 100 Gbit/s NRZ-OOK and 100 Gbit/s 4-PAM direct detection is demonstrated. The devices feature a bandwidth of 50 GHz, operate with 1.3 Vp and are of interest because of the low on-chip loss characteristics.