Publications

2015
Dutt, Avik, Kevin Luke, Sasikanth Manipatruni, Alexander L. Gaeta, Paulo Nussenzveig, and Michal Lipson. “On-Chip Optical Squeezing.” Physical Review Applied 3 (2015): 044005. Publisher's Version Abstract
We report the observation of all-optical squeezing in an on-chip monolithically integrated CMOScompatible platform. Our device consists of a low-loss silicon nitride microring optical parametric oscillator (OPO) with a gigahertz cavity linewidth. We measure 1.7 dB (5 dB corrected for losses) of subshot-noise quantum correlations between bright twin beams generated in the microring four-wave-mixing OPO pumped above threshold. This experiment demonstrates a compact, robust, and scalable platform for quantum-optics and quantum-information experiments on chip.
dutt_squeezing_prapplied_2015.pdf
2012
Padmaraju, Kishore, Noam Ophir, Qianfan Xu, Bradley Schmidt, Jagat Shakya, Sasikanth Manipatruni, Michal Lipson, and Keren Bergman. “Error-free transmission of microring-modulated BPSK.” Optics Express 20 (2012): 8681-8688. Abstract
We demonstrate the generation of error-free binary-phase-shift-keyed (BPSK) data at 5 Gb/s using a silicon microring modulator. The microring-modulated BPSK signal is propagated at fiber lengths up to 80 km, maintaining error-free performance, while demonstrating resilience to chromatic dispersion. Bit-error-rate measurements and eye diagrams show near equivalent performance of a microring-based BPSK modulator as compared to commercial LiNbO3 phase modulators. (C) 2012 Optical Society of America
Zhang, Mian, Gustavo S. Wiederhecker, Sasikanth Manipatruni, Arthur Barnard, Paul McEuen, and Michal Lipson. “Synchronization of Micromechanical Oscillators Using Light.” Physical Review Letters 109 (2012). Abstract
Synchronization, the emergence of spontaneous order in coupled systems, is of fundamental importance in both physical and biological systems. We demonstrate the synchronization of two dissimilar silicon nitride micromechanical oscillators, that are spaced apart by a few hundred nanometers and are coupled through an optical cavity radiation field. The tunability of the optical coupling between the oscillators enables one to externally control the dynamics and switch between coupled and individual oscillation states. These results pave a path toward reconfigurable synchronized oscillator networks.
2011
Wiederhecker, Gustavo S., Sasikanth Manipatruni, Sunwoo Lee, and Michal Lipson. “Broadband tuning of optomechanical cavities.” Optics Express 19, no. 3 (2011): 2782-2790. Abstract
We demonstrate broadband tuning of an optomechanical microcavity optical resonance by exploring the large optomechanical coupling of a double-wheel microcavity and its uniquely low mechanical stiffness. Using a pump laser with only 13 mW at telecom wavelengths we show tuning of the silicon nitride microcavity resonances over 32 nm. This corresponds to a tuning power efficiency of only 400 mu W/nm. By choosing a relatively low optical Q resonance (approximate to 18,000) we prevent the cavity from reaching the regime of regenerative optomechanical oscillations. The static mechanical displacement induced by optical gradient forces is estimated to be as large as 60 nm. (C) 2011 Optical Society of America
broadband_tuning_of_optomechanical_cavities.pdf
Zhang, Mian, Gustavo Wiederhecker, Sasikanth Manipatruni, Arthur Barnard, Paul McEuen, and Michal Lipson. “Synchronization of Micromechanical Oscillators Using Light.” arXiv:1112.3636v1 (2011). Abstract
Synchronization, the emergence of spontaneous order in coupled systems, is of fundamental importance in both physical and biological systems. We demonstrate the synchronization of two dissimilar silicon nitride micromechanical oscillators, that are spaced apart by a few hundred nanometers and are coupled through optical radiation field. The tunability of the optical coupling between the oscillators enables one to externally control the dynamics and switch between coupled and individual oscillation states. These results pave a path towards reconfigurable massive synchronized oscillator networks.
synchronization_of_micromechanical_oscillators_using_light.pdf
2010
Biberman, Aleksandr, Sasikanth Manipatruni, Noam Ophir, Long Chen, Michal Lipson, and Keren Bergman. “First demonstration of long-haul transmission using silicon microring modulators.” Optics Express 18 (2010): 15544-15552. Abstract
We report error-free long-haul transmission of optical data modulated using a silicon microring resonator electro-optic modulator with modulation rates up to 12.5 Gb/s. Using bit-error-rate and power penalty characterizations, we evaluate the performance of this device with varying modulation rates, and perform a comparative analysis using a commercial electro-optic modulator. We then experimentally measure the signal integrity degradation of the high-speed optical data with increasing propagation distances, induced chromatic dispersions, and bandwidth-distance products, showing error-free transmission for propagation distances up to 80 km. These results confirm the functional ubiquity of this silicon modulator, establishing the potential role of silicon photonic interconnects for chip-scale high-performance computing systems and memory access networks, optically-interconnected data centers, as well as high-performance telecommunication networks spanning large distances.
first_demonstration_of_long-haul_transmission_using_silicon_microring_modulators.pdf
Manipatruni, Sasikanth, Long Chen, and Michal Lipson. “Ultra high bandwidth WDM using silicon microring modulators.” Optics Express 18 (2010): 16858-16867. Abstract
We report 50 Gbit/s modulation capability using four silicon micro ring modulators within a footprint of 500 um2. This is the highest total modulation capability shown in silicon using compact micro-ring modulators. Using the proposed techniques, silicon nanophotonic bandwidths can meet the requirements of future CMOS interconnects by using multiple wavelengths to extend beyond single device speeds.
ultra_high_bandwidth_wdm_using_silicon_microring_modulators.pdf
Manipatruni, Sasikanth, Kyle Preston, Long Chen, and Michal Lipson. “Ultra-low voltage, ultra-small mode volume silicon microring modulator.” Optics Express 18 (2010): 18235-18242. Abstract
We show GHz modulation in a 2.5 um radius silicon micro-ring, with only 150 mV peak-peak drive voltage and an electro-optic modal volume of only 2 um3. 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.
ultra-low_voltage_ultra-small_mode_volume_silicon_microring_modulator.pdf
2009
Lira, Hugo L. R., Sasikanth Manipatruni, and Michal Lipson. “Broadband hitless silicon electro-optic switch for on-chip optical networks.” Optics Express 17 (2009): 22271-22280. Abstract
We report on the demonstration of a broadband (60 GHz), spectrally hitless, compact (20 mu m x 40 mu m), 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. (C) 2009 Optical Society of America
Preston, Kyle, Sasikanth Manipatruni, Alexander Gondarenko, Carl B. Poitras, and Michal Lipson. “Deposited silicon high-speed integrated electro-optic modulator.” Optics Express 17 (2009): 5118-5124. Abstract
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. (C) 2009 Optical Society of America
Chen, Long, Kyle Preston, Sasikanth Manipatruni, and Michal Lipson. “Integrated GHz silicon photonic interconnect with micrometer-scale modulators and detectors.” Optics Express 17 (2009): 15248-15256. Abstract
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 similar to 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. (C) 2009 Optical Society of America
Manipatruni, Sasikanth, Jacob T. Robinson, and Michal Lipson. “Optical Nonreciprocity in Optomechanical Structures.” Physical Review Letters 102 (2009). Abstract
We demonstrate that optomechanical devices can exhibit nonreciprocal behavior when the dominant light-matter interaction takes place via a linear momentum exchange between light and the mechanical structure. As an example, we propose a microscale optomechanical device that can exhibit a nonreciprocal behavior in a microphotonic platform operating at room temperature. We show that, depending on the direction of the incident light, the device switches between a high and low transparency state with more than a 20 dB extinction ratio.
2008
Manipatruni, Sasikanth, Carl B. Poitras, Qianfan Xu, and Michal Lipson. “High-speed electro-optic control of the optical quality factor of a silicon microcavity.” Optics Letters 33 (2008): 1644-1646. Abstract
We demonstrate electro-optic ultrafast control of the optical quality factor of an on-chip silicon microcavity. The micrometer-sized cavity is formed by light confinement between two microring resonators acting as frequency selective mirrors. The ring resonators are integrated into p-i-n junctions enabling ultrafast injection and extraction of carriers. We show tuning of the cavity quality factor from 20,000 to 6,000 in under 100 ps. We demonstrate both high-Q to low-Q and low-Q to high-Q transitions. (c) 2008 Optical Society of America.
Dong, Po, Stefan F. Preble, Jacob T. Robinson, Sasikanth Manipatruni, and Michal Lipson. “Inducing photonic transitions between discrete modes in a silicon optical microcavity.” Physical Review Letters 100 (2008). Abstract
We show the existence of direct photonic transitions between modes of a silicon optical microcavity spaced apart in wavelength by over 8 nm. This is achieved by using ultrafast tuning of the refractive index of the cavity over a time interval that is comparable to the inverse of the frequency separation of modes. The demonstrated frequency mixing effect, i.e., the transitions between the modes, would enable on-chip silicon comb sources which can find wide applications in optical sensing, precise spectroscopy, and wavelength-division multiplexing for optical communications and interconnects.
Manipatruni, Sasikanth, Po Dong, Qianfan Xu, and Michal Lipson. “Tunable superluminal propagation on a silicon microchip.” Optics Letters 33 (2008): 2928-2930. Abstract
We demonstrate tunable superluminal propagation in a silicon microphotonic device in a solid-state room-temperature device of tens of micrometers in dimension allowing easy integration with high-bandwidth room-temperature systems. We achieve tunable negative delays up to 85 ps and effective group indices tunable between -1158 and -312. (C) 2008 Optical Society of America
Manipatruni, Sasikanth, Rajeev K. Dokania, Bradley Schmidt, Nicolas Sherwood-Droz, Carl B. Poitras, Alyssa B. Apsel, and Miclial Lipson. “Wide temperature range operation of micrometer-scale silicon electro-optic modulators.” Optics Letters 33 (2008): 2185-2187. Abstract
We demonstrate high bit rate electro-optic In 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. (C) 2008 Optical Society of America
2007
Xu, Qianfan, Sasikanth Manipatruni, Brad Schmidt, Jagat Shakya, and Michal Lipson. “12.5 Gbit/s carrier-injection-based silicon micro-ring silicon modulators.” Optics Express 15 (2007): 430-436. Abstract
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. (c) 2007 Optical Society of America.
Schmidt, Bradley, Qianfan Xu, Jagat Shakya, Sasikanth Manipatruni, and Michal Lipson. “Compact electro-optic modulator on silicon-on-insulator substrates using cavities with ultra-small modal volumes.” Optics Express 15 (2007): 3140-3148. Abstract
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-on-insulator 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. (c) 2007 Optical Society of America.
Manipatruni, Sasikanth, Qianfan Xu, and Michal Lipson. “PINIP based high-speed high-extinction ratio micron-size silicon electro-optic modulator.” Optics Express 15 (2007): 13035-13042. Abstract
We propose an electro-optic 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 micron-size device operates at 40 Gbit/s with 12 dB extinction ratio and 2.25 fJ/bit/micron-length power dissipation. The proposed device is limited in speed only by the photon lifetime of the resonator. (c) 2007 Optical Society of America.