Publications by Year: 2013

Soltani, Mohammad, James Inman, Michal Lipson, and Michelle D. Wang. “Electro-Optofluidicis: Achieving Dynamic Control On-Chip.” Biophysical Journal 104 (2013): 503A-503A.
Saha, Kasturi, Yoshitomo Okawachi, Bonggu Shim, Jacob S. Levy, Reza Salem, Adrea R. Johnson, Mark A. Foster, Michael R. E. Lamont, Michal Lipson, and Alexander L. Gaeta. “Modelocking and femtosecond pulse generation in chip-based frequency combs.” Optics Express 21 (2013): 1335-1343. Abstract
We investigate simultaneously the temporal and optical and radio-frequency spectral properties of parametric frequency combs generated in silicon-nitride microresonators and observe that the system undergoes a transition to a mode-locked state. We demonstrate the generation of sub-200-fs pulses at a repetition rate of 99 GHz. Our calculations show that pulse generation in this system is consistent with soliton modelocking. Ultimately, such parametric devices offer the potential of producing ultra-short laser pulses from the visible to mid-infrared regime at repetition rates from GHz to THz. (C) 2013 Optical Society of America
Moss, David J., Roberto Morandotti, Alexander L. Gaeta, and Michal Lipson. “New CMOS-compatible platforms based on silicon nitride and Hydex for nonlinear optics.” Nature Photonics 7 (2013): 597-607. Abstract
Nonlinear photonic chips can generate and process signals all-optically with far superior performance to that possible electronically - particularly with respect to speed. Although silicon-on-insulator has been the leading platform for nonlinear optics, its high two-photon absorption at telecommunication wavelengths poses a fundamental limitation. We review recent progress in non-silicon CMOS-compatible platforms for nonlinear optics, with a focus on Si3N4 and Hydex (R). These material systems have opened up many new capabilities such as on-chip optical frequency comb generation and ultrafast optical pulse generation and measurement. We highlight their potential future impact as well as the challenges to achieving practical solutions for many key applications.
Luke, Kevin, Avik Dutt, Carl B. Poitras, and Michal Lipson. “Overcoming Si3N4 film stress limitations for high quality factor ring resonators.” Optics Express 21 (2013): 22829-22833. Abstract
Silicon nitride (Si3N4) ring resonators are critical for a variety of photonic devices. However the intrinsically high film stress of silicon nitride has limited both the optical confinement and quality factor (Q) of ring resonators. We show that stress in Si3N4 films can be overcome by introducing mechanical trenches for isolating photonic devices from propagating cracks. We demonstrate a Si3N4 ring resonator with an intrinsic quality factor of 7 million, corresponding to a propagation loss of 4.2 dB/m. This is the highest quality factor reported to date for high confinement Si3N4 ring resonators in the 1550 nm wavelength range. (c) 2013 Optical Society of America
Liu, David, Lucas H. Gabrielli, Michal Lipson, and Steven G. Johnson. “Transformation inverse design.” Optics Express 21 (2013): 14223-14243. Abstract
We present a new technique for the design of transformation-optics devices based on large-scale optimization to achieve the optimal effective isotropic dielectric materials within prescribed index bounds, which is computationally cheap because transformation optics circumvents the need to solve Maxwell's equations at each step. We apply this technique to the design of multimode waveguide bends (realized experimentally in a previous paper) and mode squeezers, in which all modes are transported equally without scattering. In addition to the optimization, a key point is the identification of the correct boundary conditions to ensure reflectionless coupling to untransformed regions while allowing maximum flexibility in the optimization. Many previous authors in transformation optics used a certain kind of quasiconformal map which overconstrained the problem by requiring that the entire boundary shape be specified a priori while at the same time underconstraining the problem by employing "slipping" boundary conditions that permit unwanted interface reflections. (C) 2013 Optical Society of America
Lee, Yoon Ho Daniel, Michael O. Thompson, and Michal Lipson. “Deposited low temperature silicon GHz modulator.” Optics Express 21 (2013): 26688-26692. Abstract
We demonstrate gigahertz electro-optic modulator fabricated on low temperature polysilicon using excimer laser annealing technique compatible with CMOS backend integration. Carrier injection modulation at 3 Gbps is achieved. These results open up an array of possibilities for silicon photonics including photonics on DRAM and on flexible substrates. (C) 2013 Optical Society of America
Guha, Biswajeet, Jaime Cardenas, and Michal Lipson. “Athermal silicon microring resonators with titanium oxide cladding.” Optics Express 21 (2013): 26557-26563. Abstract
We describe a novel approach for CMOS-compatible passively temperature insensitive silicon based optical devices using titanium oxide cladding which has a negative thermo-optic (TO) effect. We engineer the mode confinement in Si and TiO2 such that positive TO of Si is exactly cancelled out by negative TO of TiO2. We demonstrate robust operation of the resulting device over 35 degrees. (C) 2013 Optical Society of America
Cardenas, Jaime, Mian Zhang, Christopher T. Phare, Shreyas Y. Shah, Carl B. Poitras, Biswajeet Guha, and Michal Lipson. “High Q SiC microresonators.” Optics Express 21 (2013): 16882-16887. Abstract
We demonstrate photonic devices based on standard 3C SiC epitaxially grown on silicon. We achieve high optical confinement by taking advantage of the high stiffness of SiC and undercutting the underlying silicon substrate. We demonstrate a 20 mu m radius suspended microring resonator with Q=14,100 fabricated on commercially available SiC-on-silicon substrates. (C) 2013 Optical Society of America
Cardenas, Jaime, Paul A. Morton, Jacob B. Khurgin, Austin Griffith, Carl B. Poitras, Kyle Preston, and Michal Lipson. “Linearized silicon modulator based on a ring assisted Mach Zehnder inteferometer.” Optics Express 21 (2013): 22549-22557. Abstract
We demonstrate a Linearized Ring Assisted Mach-Zehnder Interferometer (L-RAMZI) modulator in a miniature silicon device. We measure a record high degree of linearization for a silicon device, with a Spurious Free Dynamic Range (SFDR) of 106dB/Hz(2)/(3) at 1GHz, and 99dB/Hz(2)/(3) at 10GHz. (c) 2013 Optical Society of America