A 40Gb/s PAM4 optical DAC silicon microring resonator modulator transmitter

PAM4 modulation is currently being implemented in high-speed wireline communication standards in order to increase bandwidth density. This paper presents a transmitter which utilizes a low-area silicon microring resonator modulator with two separate phase shifter segments to realize high-speed PAM4 modulation with an optical DAC approach. The optical DAC is designed with an optimized MSB/LSB segment size ratio of 1.9:1 to generate a uniform four level output with independent MSB/LSB two-level NRZ drivers. Two differential high-swing segmented pulsed-cascode output stages drive the MSB/LSB segments with independent edge-rate and level controls that compensate for output level spacing and eye skew. The hybrid integrated prototype, with the optical DAC microring modulator fabricated in a 130nm silicon photonic process and the transmitter circuitry fabricated in a GP 65nm CMOS process, achieves 40Gb/s operation at 4.38mW/Gb/s when driving each differential terminal of the segmented depletion-mode microring modulator with 4.4Vppd swing.

[1]  George Panotopoulos,et al.  Universal Photonic Interconnect for Data Centers , 2017, Journal of Lightwave Technology.

[2]  S. Palermo,et al.  A 40 Gb/s PAM4 silicon microring resonator modulator transmitter in 65nm CMOS , 2016, 2016 IEEE Optical Interconnects Conference (OI).

[3]  Rajeev J. Ram,et al.  A 40-Gb/s PAM-4 Transmitter Based on a Ring-Resonator Optical DAC in 45-nm SOI CMOS , 2017, IEEE Journal of Solid-State Circuits.

[4]  B. Blampey,et al.  20Gb/s PAM-4 transmission from 35 to 90°C by modulating a Silicon Ring Resonator Modulator with 2Vpp , 2015, 2015 Optical Fiber Communications Conference and Exhibition (OFC).

[5]  A. Yariv.  Universal relations for coupling of optical power between microresonators and dielectric waveguides , 2000 .

[6]  Jonathan Proesel,et al.  A monolithic 56 Gb/s CMOS integrated nanophotonic PAM-4 transmitter , 2015, 2015 IEEE Optical Interconnects Conference (OI).

[7]  Binhao Wang,et al.  A 25 Gb/s, 4.4 V-Swing, AC-Coupled Ring Modulator-Based WDM Transmitter with Wavelength Stabilization in 65 nm CMOS , 2015, IEEE Journal of Solid-State Circuits.

[8]  Binhao Wang,et al.  Energy efficiency comparisons of NRZ and PAM4 modulation for ring-resonator-based silicon photonic links , 2015, 2015 IEEE 58th International Midwest Symposium on Circuits and Systems (MWSCAS).

[9]  R. G. Beausoleil,et al.  30Gbit/s PAM-4 transmission by modulating a dual silicon ring resonator modulator , 2016, 2016 IEEE Optical Interconnects Conference (OI).

[10]  Xin Yin,et al.  40 Gb/s PAM-4 Transmitter IC for Long-Wavelength VCSEL Links , 2015, IEEE Photonics Technology Letters.

[11]  Vladimir Stojanovic,et al.  29.3 A 40Gb/s PAM-4 transmitter based on a ring-resonator optical DAC in 45nm SOI CMOS , 2017, 2017 IEEE International Solid-State Circuits Conference (ISSCC).

[12]  Daoxin Dai,et al.  Silicon Nanophotonic Integrated Devices for On-Chip Multiplexing and Switching , 2017, Journal of Lightwave Technology.

[13]  Ashok V. Krishnamoorthy,et al.  A Monolithic 25-Gb/s Transceiver With Photonic Ring Modulators and Ge Detectors in a 130-nm CMOS SOI Process , 2012, IEEE Journal of Solid-State Circuits.

[14]  Lin Sen,et al.  29.3 A 40Gb/s PAM-4 transmitter based on a ring-resonator optical DAC in 45nm SOI CMOS , 2017 .

[15]  R. Soref,et al.  Electrooptical effects in silicon , 1987 .

[16]  W. Shi,et al.  60 Gb/s PAM-4 operation with a silicon microring modulator , 2015, 2015 IEEE 12th International Conference on Group IV Photonics (GFP).