Low-power silicon-organic hybrid (SOH) modulators for advanced modulation formats

Abstract

Abstract:We demonstrate silicon-organic hybrid (SOH) electro-optic modulators that enable quadrature phase-shift keying (QPSK) and 16-state quadrature amplitude modulation (16QAM) with high signal quality and record-low energy consumption. SOH integration combines highly efficient electro-optic organic materials with conventional silicon-on-insulator (SOI) slot waveguides, and allows to overcome the intrinsic limitations of silicon as an optical integration platform. We demonstrate QPSK and 16QAM signaling at symbol rates of 28 GBd with peak-to-peak drive voltages of 0.6 V pp . For the 16QAM experiment at 112 Gbit/s, we measure a bit error ratio of 5.1 × 10 ˗5 and a record-low energy consumption of only 19 fJ/bit. Shastri, "112Gb/s DP-QPSK transmission over 2427km SSMF using small-size silicon photonic IQ modulator and low-power CMOS driver," in Optical Fiber Communication Conference, 2013 (OSA, 2013 Freude, C. Koos, and J. Leuthold, "Low-loss silicon strip-to-slot mode converters," IEEE Photon. J. 5(1), 2200409 (2013). 32. F. Derr, "Coherent optical QPSK intradyne system: concept and digital receiver realization," J. LightwaveTechnol. 10(9), 1290-1296 (1992 Huebner, C. Koos, J. Becker, W. Freude, and J. Leuthold, "Error vector magnitude as a performance measure for advanced modulation formats," IEEE Photon.

Silicon-organic hybrid (SOH) modulators for intensity-modulation / direct-detection links with line rates of up to 120 Gbit/s

“…This is significantly smaller than the 410 fJ/bit demonstrated for a 4.8 mm long depletion-type modulator at a comparable PAM4 line rate of 112 Gbit/s [12]. Note that even higher data rates can be achieved by using coherent transmission schemes along with advanced modulation formats such as 16-state quadrature amplitude modulation (16QAM) [35][36][37]. However, the associated transmitter and receiver circuitry is technically much more demanding than the rather simple IM/DD scheme used here, which does not require powerful DSP or coherent receivers.…”

Silicon-Organic Hybrid (SOH) and Plasmonic-Organic Hybrid (POH) Integration

“…SOH modulators can be designed for low energy consumptions of only a few femtojoule per bit [19], [20] or for high modulation frequencies of up to 100 GHz [21]. Moreover, SOH devices are perfectly suited for advanced modulation formats such as quadrature phase-shift keying (QPSK) and 16-state quadrature-amplitude modulation (16QAM) [22], [23]. The high modulation efficiency of SOH modulators allows to drive the devices directly from binary CMOS output ports of standard field-programmable gate arrays (FPGA) for generating advanced modulation formats without the use of digital-toanalog converters or radio-frequency (RF) drive amplifiers [24].…”

Generation of 64 GBd 4ASK signals using a silicon-organic hybrid modulator at 80°C

“…Due to the high modulation efficiency, the MZM can be as short as 750 µm. The transmission line of the modulator is designed for a characteristic impedance of 50 Ω, matched [17,22] to the characteristic impedance of common RF equipment. The bandwidth of the SOH device is typically limited by the RC time constant formed by the slot capacitance and the finite conductivity of the resistive slabs.…”

“…In transmission experiments, SOH MZM have been demonstrated to enable data rates of 100 Gbit/s using simple OOK [16]. Similarly, SOH IQ modulators are perfectly suited for signaling with higher-order modulation formats such as 16QAM [17]. Symbol rates of up to 40 GBd and line rates of up 160 Gbit/s have been demonstrated experimentally [18].…”