High-Speed Silicon-Organic Hybrid (SOH) Modulator with 1.6 fJ/bit and 180 pm/V In-Device Nonlinearity

Abstract

We report on a 40 Gbit/s silicon-organic hybrid (SOH) modulator with 11 dB extinction ratio.A novel electro-optic chromophore with record in-device nonlinearity of 180 pm/V leads to V  L = 0.5 Vmm and a low energy consumption of 1.6 fJ/bit at 12.5 Gbit/s. IntroductionEnergy-efficient silicon electro-optic modulators are key components for future short-distance interconnects in data centers and highperformance computers [1]. Targeted energy consumptions are tens of fJ/bit for dense offchip connections, and a few fJ/bit for global onchip connections [1]. Over the last years, a variety of silicon modulators has been demonstrated based on free-carrier depletion, or injection in pn-diodes, or based on metal-oxidesemiconductor (MOS) structures [2,3]. Carrier injection devices have typically very small voltage-length products of π V L = 0.36 V mm [4], but the large carrier lifetime calls for pre-emphasis and limits the modulation speed to 20 GHz. The modulation energy per bit is usually in the pJrange due to the forward bias of the diode. Carrier depletion modulators, in contrast, have been demonstrated to operate at data rates of up to 50 Gbit/s [5], but typically with

High-Speed, Low Drive-Voltage Silicon-Organic Hybrid Modulator Based on a Binary-Chromophore Electro-Optic Material

“…It has recently been shown that in-device EO coefficient of up to r 33 = 180 pm/V can be achieved by using so-called monolithic EO materials, that do not require a polymer matrix to prevent detrimental dipole-dipole interaction and that have a molecular structure that is engineered for enhanced poling efficien y [15], [17]. Here we expand on these finding by investigating two different material systems: A neat material that consists of the multi-chromophore dendritic molecule PSLD41 [29], and a mixture of the chromophores YLD124 and PSLD41 (25:75 wt.%), also referred to as binary chromophore organic glass (BCOG) [30].…”

“…Here, light is guided in a silicon waveguide core and nonlinear optical effects of second order are realized by exploiting evanescent interaction of the guided light mode with an organic electro-optic cladding material [10]- [12]. Specificall tailored organic materials with strong linear EO effect (Pockels effect) enable small voltagelength products and high modulation bandwidth simultaneously [10], [13]- [15]. So far, the most commonly used cladding materials for SOH integration are polymers doped by EO chromophore molecules [11], [16].…”

100 GHz silicon–organic hybrid modulator

“…The use of materials with a stronger nonlinearity can further improve this value by an order of magnitude. 23,24 ACKNOWLEDGMENTS …”

Silicon-organic hybrid (SOH) frequency comb sources for terabit/s data transmission

“…The silicon waveguides are fabricated on a SOI wafer with a 2 µm thick buried oxide and a 220 nm thick device layer using 193 nm deep-UV lithography. After processing, the SOI waveguides are covered with the electro-optic chromophore DLD164 [30], which entirely fills the slot. The electro-optic cladding is applied by spin coating and poled at elevated temperatures with a DC voltage applied across the slotline electrodes.…”