The recent AI boom requires more focus on energy-efficient and scalable optical interconnects. Silicon Photonics is enabling technology to satisfy growing demand. However, the lack of lasers and high-performance modulators hinders wide-scale adoption. Therefore, we present a heterogeneously integrated Indium Phosphide electro-absorption modulator with Silicon waveguides. We demonstrate up to 256 Gb/s on-off keying, 340 Gb/s 4-level pulse amplitude modulation, 375 Gb/s 6-level pulse amplitude modulation, and 360 Gb/s 8-level pulse amplitude modulation transmission over 500 m and 6 km of single-mode fiber with performance satisfying requirements of 6.25% overhead hard-decision forward error correction threshold of 4.5x10(-3). Additionally, we investigate the modulator at 200 Gb/s per lane scenarios, demonstrating excellent performance with a simple seven-tap feed-forward equalizer.

Development of Data Center based computing technology require energy efficient high-speed transmission links. This leads to optical amplification-free intensity modulation and direct detection (IM/DD) systems with low complexity equalization compliant with IEEE standardized electrical interfaces. Switching from on-off keying to multi-level pulse amplitude modulation would allow to reduce lane count for next generation Ethernet interfaces. We characterize 106.25 Gbaud on-off keying, 4-level and 6-level pulse amplitude modulation links using two integrated transmitters: O-band directly modulated laser and C-band externally modulated laser. Simple feed forward or decision feedback equalizer is used. We demonstrate 106.25 Gbaud on-off keying links operating without forward error correction for both transmitters. We also show 106.25 Gbaud 4-level and 6-level pulse amplitude modulation links with performance below 6.25% overhead hard-decision forward error threshold of 4.5 x 10(-3). Furthermore, for EML-based transmitter we achieve 106.25 Gbaud 4-level pulse amplitude modulation performance below KP-FEC threshold of 2.2 x 10(-4). That shows that we can use optics to support (2x)100 Gbps Ethernet on single lambda at expense of simple forward error correction.

We report on an optical-amplification-free O-band SiP RRM-based IM/DD link with unprecedented data rates achieved below the 6.25%-OH HD-FEC threshold. Transmission of 206 Gbaud OOK and 112 Gbaud PAM4 over 500-m SMF are successfully demonstrated. (c) 2024 The Author(s)

We demonstrate a record 170 Gbaud on-off keying C-band silicon photonics ring resonator modulator-based transmitter with performance below the 6.7% overhead HD-FEC threshold after optical back-to-back and transmission over 100 meters of single mode fiber.

We demonstrate an optical-amplification-free 245 Gbaud OOK and 140 Gbaud PAM4 links using a C-band SiP RRM-based transmitter with performance below the 6.25% overhead hard-decision forward error correction threshold after 100 meters of SMF.

We demonstrate an InP EAM with Si waveguides and achieve 256 Gbaud OOK, 170 Gbaud PAM4, 150 Gbaud PAM6, and 120 Gbaud PAM8 transmission over 500 meters of SMF below 6.25% OH HD-FEC threshold.

Silicon photonics (SiP) is a key enabling technology for high-symbol rate communication to enable future 800 Gbps and 1.6 Tbps solutions in scalable and energy efficiency way. The 800G pluggable multi-source agreement (MSA) suggests that intensity-modulated direct-detection (IM/DD) is the most sustainable way forward [1]. Recent advances [2–12] in SiP enable dense integration, high yield, and low energy consumption for optical interconnects. Monolithic integration of SiP and complementary metal-oxide semiconductor (CMOS) eliminates need of additional packaging and integration allowing to introduce compact arrayed waveguide grating routers [2] or extremely efficient wavelength division multiplexing filters [3]. All silicon avalanche photodiode [4] has demonstrated $0.73 \mathrm{~A} / \mathrm{W}$, and more than 38 GHz RF bandwidth in O-band operation. To ensure high symbol rate operation high operational bandwidth of each transceiver component is necessary. High-bandwidth SiP slow light modulator [5] and wide free spectral range SiP ring resonator modulator (RRM) [6] have been demonstrated. On-off keying (OOK) at highest symbol rate should be considered thanks to high energy efficiency and simple driving electronics. At expense of more complex driver electronics pulse amplitude modulation with 4 levels also can be considered if the modulator extinction ratio supports it. SiP RRM have unique advantages as low power consumption, small footprint, high scalability, suitability for multichannel operation and easier integration with CMOS drivers and electronics. Recently SiP RRM was used to demonstrate 160 Gbaud OOK [7]. SiP RRM with integrated laser demonstrated 128 Gbaud OOK/PAM4 [8]. Multichannel integration advantages of SiP RRM have been shown by implementing $4 \times 112 \mathrm{Gbps}$ [9], $4 \times 224 \mathrm{Gbps}$ [10] and $16 \times 56 \mathrm{Gbps}$ [11] in O-band as well $32 \times 16 \mathrm{Gbps}$ [12] in C-band. In this paper, we report on several SiP RRM-based transmitters to achieve high symbol rate with performance below 6.7% overhead (OH) hard-decision forward error correction (HD-FEC) threshold of $4.5 \times 10^{-3}$ [13]. We demonstrate on-off keying (OOK) transmission for optical-back-to-back and after transmission over 100 meters of single mode fiber (SMF). RRMs are characterized with [14].

The booming internet traffic sets highly challenging requirements for high-speed computing where low latency is required. This leads to a choice of intensity modulation and direct detection system with the highest baudrate possible. Furthermore, record baudrate supporting modulators will be the key technology for future optical interconnect applications. Therefore, we demonstrated silicon photonics and indium phosphide modulators at highest possible sysmbolrate.

Nanoplasmonics as enabler of room-temperature quantum nanophotonic networks (Invited), Ortwin Hess Coffee break (11:00 -11:20) Track 1 -Room 2.1 Track 2 -Room 2.2 Track 3 -Room 2.3 Track 4 -Room 3.1 Track 5 -Room 3.2 Track 6

We demonstrate a record 310/256 Gbaud OOK, 197/145 Gbaud PAM4, and 160/116 Gbaud PAM6 EML/DML-based IM/DD links without any optical amplification with performance below the 6.25% overhead HD-FEC threshold after 100-m/6-km SMF, respectively.

Silicon photonics (SiP) is a key enabling technology for high-baudrate communication. It is a key technology for future 800 Gbps and 1.6 Tbps solutions to meet the ever-increasing demands. The 800G pluggable multi-source agreement (MSA) suggests that intensity-modulated direct-detection (IM/DD) is the most sustainable way forward [1]. The high operational bandwidth of each transceiver component is essential. An ultra-compact SiP slow light modulator with record-high bandwidth of 110 GHz shows the potential [2]. Therefore, both multilevel pulse amplitude modulation (PAM) and on-off keying (OOK) should be considered. SiP offers excellent production yield and has a substantial role in optical interconnects. SiP ring resonator modulators (RRM) have unique advantages like a small footprint, simple driver configuration, low power consumption, and suitability for multichannel applications. On the other hand, the SiP Mach-Zehnder modulator (MZM) offers differential drive benefits.

We demonstrate a record 240 Gbaud on-off keying, 150 Gbaud 4-level pulse amplitude modulation, and 100 Gbaud 6-level pulse amplitude modulation SiP MZM-based transmitter with performance below the 6.25% overhead HD-FEC threshold. We also show a 160 Gbaud on-off keying SiP RRM-based transmitter.

We demonstrate for the first time generation of 16-state quadrature amplitude modulation (16QAM) signals at a symbol rate of 40 GBd using silicon-based modulators. Our devices exploit silicon-organic hybrid integration, which combines silicon-on-insulator slot waveguides with electro-optic cladding materials to realize highly efficient phase shifters. The devices enable 16QAM signaling and quadrature phase shift keying at symbol rates of 40 GBd and 45 GBd, respectively, leading to line rates of up to 160 Gb/s on a single wavelength and in a single polarization. This is the highest value demonstrated by a silicon-based device up to now. The energy consumption for 16 QAM signaling amounts to less than 120 fJ/bit-one order of magnitude below that of conventional silicon photonic 16QAM modulators.