H.J.S. Dorren

Challenges for Optically Enabled High-Radix Switches for Data Center Networks

We discuss challenges for optically enabled high-radix switches in data centers. We highlight the clear advantages of using high-radix switches and explain why coupling such switches with midboard optics can be a winning solution. We further analyze the trends in pluggable transceivers and data center switches and indicate that if current scaling trends are set to continue, very different hardware, software, and architectures should be adopted to support future data centers networks.

A novel 3D stacking method for opto-electronic dies on CMOS ICs

A high speed, high density and potentially low cost solution for realizing a compact transceiver module is presented in this paper. It is based on directly bonding an Opto-electronic die on top of CMOS IC chip and creating a photoresist ramp to bridge the big step (around 220μm) from Opto-electronic pads to CMOS IC pads. The required electrical connection between them is realized lithographically with a process than can be scaled to full wafer production. A 12-channel transmitter based on the technique was fabricated and test shows good performance up to 12.5 Gb/s/ch. ©2012 Optical Society of America OCIS codes: (200.0200) Optics in computing; (200.4650) Optical interconnects; (130.0250) Optoelectronics; (130.3120) Integrated optics devices; (140.7260) Vertical cavity surface emitting lasers; (220.3740) Lithography. References and links 1. D. A. B. Miller, “Rationale and challenges for optical interconnects to electronic chips,” Proc. IEEE 88(6), 728– 749 (2000). 2. D. A. B. Miller, “Device requirements for optical interconnects to silicon chips,” Proc. IEEE 97(7), 1166–1185 (2009). 3. H. J. S. Dorren, P. Duan, O. Raz, and R. P. Luijten, “Fundamental bounds for photonic interconnects,” 13th International Conference on Transparent Optical Networks (ICTON, Stockholm, 2011), paper Mo.C1.1. 4. L. Dellmann, U. Drechsler, T. Morf, H. Rothuizen, R. Stutz, J. Weiss, and M. Despont, “3D opto-electrical device stacking on CMOS,” Microelectron. Eng. 87(5-8), 1210–1212 (2010). 5. C. L. Schow, F. E. Doany, A. V. Rylyakov, B. G. Lee, C. V. Jahnes, Y. H. Kwark, C. W. Baks, D. M. Kuchta, and J. A. Kash, “A 24-Channel, 300 Gb/s, 8.2 pJ/bit, full-duplex fiber-coupled optical transceiver module based on a single “Holey” CMOS IC,” J. Lightwave Technol. 29(4), 542–553 (2011). 6. F. E. Doany, B. G. Lee, A. V. Rylyakov, D. M. Kuchta, C. Baks, C. Jahnes, F. Libsch, and C. L. Schow, “Terabit/sec VCSEL-based parallel optical module based on Holey CMOS transceiver IC”. In Proceeding of the Optical Fiber communication conference (OFC/NFOEC, Los Angeles, 2012), PDP5D.9. 7. P. Duan, O. Raz, B. E. Smalbrugge, J. Duis, and H. J. S. Dorren, “Chip-to-chip interconnects based on 3D stacking of opto-electrical dies on Si, ” in the Proc. SPIE. 8267, Optoelectronic Interconnects XII, 82670U (San Francisco, 2012).

Fabry-Pérot QDash mode-locked laser for sub-harmonic all-optical clock recovery and demultiplexing of 160 and 320 Gb/s RZ coherent signals

In this paper, we present the experimental investigation of all-optical clock recovery at 40 Gb/s from RZ coherent signal at bit rates of 160 and 320 Gb/s based on a FP- QDash modelocked laser. The recovered clock is evaluated with phase noise and timing jitter measurements and used to demultiplex the high bit rates to tributaries at 40 Gb/s. The recovered clock at 320 Gb/s retrieves an outstanding RMS timing jitter of 45 fs.

Scaling limits for optical interconnects: Directly modulated versus externally modulated links

We establish a lower bound on the energy-per-bit required for transmitting information using a photonic channel. We include in our analysis the energy required to convert information from the electronic to the photonic domain and back. We investigate links that employ a directly modulated laser as well as an external modulator. We show that the power dissipation of the channel also imposes a bound on the bandwidth density.