Sasikanth Manipatruni

12.5 Gbit/s carrier-injection-based silicon micro-ring silicon modulators

We show a scheme for achieving high-speed operation for carrier-injection based silicon electro-optical modulator, which is optimized for small size and high modulation depth. The performance of the device is analyzed theoretically and a 12.5-Gbit/s modulation with high extinction ratio >9dB is demonstrated experimentally using a silicon micro-ring modulator.

Integrated GHz silicon photonic interconnect with micrometer-scale modulators and detectors

We report an optical link on silicon using micrometer-scale ring-resonator enhanced silicon modulators and waveguide-integrated germanium photodetectors. We show 3 Gbps operation of the link with 0.5 V modulator voltage swing and 1.0 V detector bias. The total energy consumption for such a link is estimated to be approximately 120 fJ/bit. Such a compact and low power monolithic link is an essential step towards large-scale on-chip optical interconnects for future microprocessors.

High Speed Carrier Injection 18 Gb/s Silicon Micro-ring Electro-optic Modulator

We experimentally demonstrate electrooptic modulation in silicon at 18 Gbps (NRZ) in a micro-ring of 12 micron diameter using a pre-emphasis technique. Device simulations indicate that this technique can extend the bit rate to 40 Gbps.

Synchronization of micromechanical oscillators using light

Synchronization on the nanoscale has a wide range of applications ranging from timing, navigation, signal processing, microwave communication and novel computing and memory concepts. Existing coupled micromechanical oscillators suffer from limited range, neighborhood restriction and non-configurable coupling which limit the control, physical size and possible topologies of complex oscillator networks [1]. Here, we demonstrate the synchronization of two micromechanical oscillators, which are actuated and coupled by optical radiation field. We show that the coupling between the two oscillators can be tuned continuously from uncoupled to maximally coupled. These results pave a path towards massive and long-range synchronized oscillator networks.

Compact electro-optic modulator on silicon-on-insulator substrates using cavities with ultra-small modal volumes.

We experimentally demonstrate a micron-size electro-optic modulator using a high-index-contrast silicon Fabry-Perot resonator cavity. This compact device consists of a 1-D cavity formed within a single mode silicon channel waveguide and an embedded p-i-n junction on a silicon-oninsulator platform. The entire device is 6.0 microns in length. We demonstrate modulation depths as large as 5.87 dB at speeds of 250 Mbps limited only by fabrication imperfections, with optimized theoretical speeds of several Gbps.

Deposited silicon high-speed integrated electro-optic modulator

We demonstrate a micrometer-scale electro-optic modulator operating at 2.5 Gbps and 10 dB extinction ratio that is fabricated entirely from deposited silicon. The polycrystalline silicon material exhibits properties that simultaneously enable high quality factor optical resonators and sub-nanosecond electrical carrier injection. We use an embedded p(+)n(-)n(+) diode to achieve optical modulation using the free carrier plasma dispersion effect. Active optical devices in a deposited microelectronic material can break the dependence on the traditional single layer silicon-on-insulator platform and help lead to monolithic large-scale integration of photonic networks on a microprocessor chip.

Broadband hitless silicon electro-optic switch for on-chip optical networks

We report on the demonstration of a broadband (60 GHz), spectrally hitless, compact (20 microm x 40 microm), fast (7 ns) electro-optical switch. The device is composed of two coupled resonant cavities, each with an independently addressable PIN diode. This topology enables operation of the switch without perturbing adjacent channels in a wavelength division multiplexing (WDM) system.

Wide temperature range operation of micrometer-scale silicon electro-optic modulators

We demonstrate high bit rate electro-optic modulation in a resonant micrometer-scale silicon modulator over an ambient temperature range of 15 K. We show that low bit error rates can be achieved by varying the bias current through the device to thermally counteract the ambient temperature changes. Robustness in the presence of thermal variations can enable a wide variety of applications for dense on chip electronic photonic integration.

Ultra-low voltage, ultra-small mode volume silicon microring modulator

We show GHz modulation in a 2.5 microm radius silicon micro-ring, with only 150 mV peak-peak drive voltage and an electro-optic modal volume of only 2 microm(3). The swing voltage and the micro-ring modulator are the smallest demonstrations so-far in silicon. The presented approach lays the ground work for a new class of high speed low voltage modulators enabling, seamless integration of nanophotonics with low voltage digital CMOS nano-electronics.

PINIP based high-speed high-extinction ratio micron-size silicon electrooptic modulator.

We propose an electrooptic device in silicon based on a p-i-n-i-p device structure for charge transport. The proposed device exhibits carrier injection time of 10 ps and extraction time of 15 ps enabling 100 GHz operation. When integrated into a resonator the proposed micron-size device operates at 40 Gb/s with 12 dB extinction ratio and 4fJ/bit/micron-length power dissipation, limited in speed only by the photon lifetime of the resonator.