Abstract

For exascale computing applications, viable optical solutions will need to operate using low voltage signaling and with low power consumption. In this work, the first differentially signaled silicon resonator is demonstrated which can provide a 5dB extinction ratio using 3fJ/bit and 500mV signal amplitude at 10Gbps. Modulation with asymmetric voltage amplitudes as low as 150mV with 3dB extinction are demonstrated at 10Gbps as well. Differentially signaled resonators simplify and expand the design space for modulator implementation and require no special drivers.

© 2011 OSA

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. Q. Xu, B. Schmidt, S. Pradhan, and M. Lipson, “Micrometre-scale silicon electro-optic modulator,” Nature 435(7040), 325–327 (2005).
    [CrossRef] [PubMed]
  2. S. Manipatruni, Q. Xu, B. Schmidt, J. Shakya, and M. Lipson, “High speed carrier injection 18 Gb/s silicon micro-ring electro-optic modulator,” in Proceedings of LEOS (2007), 537–538.
  3. P. Dong, S. Liao, D. Feng, H. Liang, D. Zheng, R. Shafiiha, C.-C. Kung, W. Qian, G. Li, X. Zheng, A. V. Krishnamoorthy, and M. Asghari, “Low Vpp, ultralow-energy, compact, high-speed silicon electro-optic modulator,” Opt. Express 17(25), 22484–22490 (2009), http://www.opticsinfobase.org/abstract.cfm?URI=oe-17-25-22484 .
    [CrossRef] [PubMed]
  4. G. Reed, F. Y. Gardes, G. Z. Mashanovich, Y. Hu, D. Thomson, G. Rasigade, D. Marris-Morini, and L. Vivien, “Recent developments in silicon optical modulators” in Integrated Photonics Research, Silicon and Nanophotonics, OSA Technical Digest (CD) Optical Society of America (2010), paper IWA1.
  5. M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Low-voltage, compact, depletion-mode, silicon Mach–Zehnder modulator,” IEEE J. Sel. Top. Quantum Electron. 16, 159–164 (2010).
  6. M. R. Watts, D. C. Trotter, R. W. Young, and A. L. Lentine, “Ultralow power silicon microdisk modulators and switches,” Group IV Photonics, 5th IEEE International Conference on, (2008) doi: 10.1109/GROUP4.2008.4638077 URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4638077&isnumber=4638071 .
    [CrossRef]
  7. W. A. Zortman, M. R. Watts, D. C. Trotter, R. W. Young, and A. L. Lentine, “Low-power high-speed silicon microdisk modulators,” Lasers and Electro-Optics (CLEO) and Quantum Electronics and Laser Science Conference (QELS), (2010).
  8. P. Dong, S. Liao, H. Liang, W. Qian, X. Wang, R. Shafiiha, D. Feng, G. Li, X. Zheng, A. V. Krishnamoorthy, and M. Asghari, “High-speed and compact silicon modulator based on a racetrack resonator with a 1 V drive voltage,” Opt. Lett. 35(19), 3246–3248 (2010), http://www.opticsinfobase.org/abstract.cfm?URI=ol-35-19-3246 .
    [CrossRef] [PubMed]
  9. G. Li, X. Zheng, J. Yao, H. Thacker, I. Shubin, Y. Luo, K. Raj, J. E. Cunningham, and A. V. Krishnamoorthy, “25Gb/s 1V-driving CMOS ring modulator with integrated thermal tuning,” Opt. Express 19(21), 20435–20443 (2011).
    [CrossRef] [PubMed]
  10. M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Vertical junction silicon microdisk modulators and switches,” Opt. Express 19(22), 21989–22003 (2011), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-22-21989 .
    [CrossRef] [PubMed]
  11. S. Manipatruni, K. Preston, L. Chen, and M. Lipson, “Ultra-low voltage, ultra-small mode volume silicon microring modulator,” Opt. Express 18(17), 18235–18242 (2010), http://www.opticsinfobase.org/abstract.cfm?URI=oe-18-17-18235 .
    [CrossRef] [PubMed]
  12. A. V. Krishnamoorthy, R. Ho, X. Zheng, H. Schwetman, J. Lexau, P. Koka, G. Li, I. Shubin, and J. E. Cunningham, “Computer systems based on silicon photonic interconnects,” Proceedings of the IEEE, 97,1337–1361, (2009) doi: 10.1109/JPROC.2009.2020712. URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5071306&isnumber=5075744 .
    [CrossRef]
  13. P. M. Kogge, ed., “ExaScale Computing Study: Technology Challenges in Achieving Exascale Systems” Univ. of Notre Dame, CSE Dept. Tech. Report TR-2008–13, (2008).
  14. Y. Berg, O. Mirmotahari, J. G. Lomsdalen, and S. Aunet, “High speed ultra low voltage CMOS inverter” Symposium on VLSI, 2008. ISVLSI '08. IEEE Computer Society Annual, 122–127, (2008) doi: 10.1109/ISVLSI.2008.23.
    [CrossRef]
  15. Intel Quick Path Architecture, http://www.intel.com/technology/quickpath/introduction.pdf (2009).
  16. K. Byungsub and V. Stojanovic, “A 4Gb/s/ch 356fJ/b 10mm equalized on-chip interconnect with nonlinear charge-injecting transmit filter and transimpedance receiver in 90nm CMOS” Solid-State Circuits Conference - Digest of Technical Papers, 2009. ISSCC 2009. IEEE International, 66–67,67a, (2009) doi: 10.1109/ISSCC.2009.4977310. URL, http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4977310&isnumber=4977283 .
    [CrossRef]
  17. J.-S. Seo, R. Ho, J. Lexau, M. Dayringer, D. Sylvester, and D. Blaauw, “High-bandwidth and low-energy on-chip signaling with adaptive pre-emphasis in 90nm CMOS” Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2010 IEEE International, 182–183, (2010) doi: 10.1109/ISSCC.2010.5433993. URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5433993&isnumber=5433812 .
    [CrossRef]

2011

2010

2009

2005

Q. Xu, B. Schmidt, S. Pradhan, and M. Lipson, “Micrometre-scale silicon electro-optic modulator,” Nature 435(7040), 325–327 (2005).
[CrossRef] [PubMed]

Asghari, M.

Chen, L.

Cunningham, J. E.

Dong, P.

Feng, D.

Krishnamoorthy, A. V.

Kung, C.-C.

Lentine, A. L.

M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Vertical junction silicon microdisk modulators and switches,” Opt. Express 19(22), 21989–22003 (2011), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-22-21989 .
[CrossRef] [PubMed]

M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Low-voltage, compact, depletion-mode, silicon Mach–Zehnder modulator,” IEEE J. Sel. Top. Quantum Electron. 16, 159–164 (2010).

Li, G.

Liang, H.

Liao, S.

Lipson, M.

Luo, Y.

Manipatruni, S.

Pradhan, S.

Q. Xu, B. Schmidt, S. Pradhan, and M. Lipson, “Micrometre-scale silicon electro-optic modulator,” Nature 435(7040), 325–327 (2005).
[CrossRef] [PubMed]

Preston, K.

Qian, W.

Raj, K.

Schmidt, B.

Q. Xu, B. Schmidt, S. Pradhan, and M. Lipson, “Micrometre-scale silicon electro-optic modulator,” Nature 435(7040), 325–327 (2005).
[CrossRef] [PubMed]

Shafiiha, R.

Shubin, I.

Thacker, H.

Trotter, D. C.

M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Vertical junction silicon microdisk modulators and switches,” Opt. Express 19(22), 21989–22003 (2011), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-22-21989 .
[CrossRef] [PubMed]

M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Low-voltage, compact, depletion-mode, silicon Mach–Zehnder modulator,” IEEE J. Sel. Top. Quantum Electron. 16, 159–164 (2010).

Wang, X.

Watts, M. R.

M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Vertical junction silicon microdisk modulators and switches,” Opt. Express 19(22), 21989–22003 (2011), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-22-21989 .
[CrossRef] [PubMed]

M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Low-voltage, compact, depletion-mode, silicon Mach–Zehnder modulator,” IEEE J. Sel. Top. Quantum Electron. 16, 159–164 (2010).

Xu, Q.

Q. Xu, B. Schmidt, S. Pradhan, and M. Lipson, “Micrometre-scale silicon electro-optic modulator,” Nature 435(7040), 325–327 (2005).
[CrossRef] [PubMed]

Yao, J.

Young, R. W.

M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Vertical junction silicon microdisk modulators and switches,” Opt. Express 19(22), 21989–22003 (2011), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-22-21989 .
[CrossRef] [PubMed]

M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Low-voltage, compact, depletion-mode, silicon Mach–Zehnder modulator,” IEEE J. Sel. Top. Quantum Electron. 16, 159–164 (2010).

Zheng, D.

Zheng, X.

Zortman, W. A.

M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Vertical junction silicon microdisk modulators and switches,” Opt. Express 19(22), 21989–22003 (2011), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-22-21989 .
[CrossRef] [PubMed]

M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Low-voltage, compact, depletion-mode, silicon Mach–Zehnder modulator,” IEEE J. Sel. Top. Quantum Electron. 16, 159–164 (2010).

IEEE J. Sel. Top. Quantum Electron.

M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, “Low-voltage, compact, depletion-mode, silicon Mach–Zehnder modulator,” IEEE J. Sel. Top. Quantum Electron. 16, 159–164 (2010).

Nature

Q. Xu, B. Schmidt, S. Pradhan, and M. Lipson, “Micrometre-scale silicon electro-optic modulator,” Nature 435(7040), 325–327 (2005).
[CrossRef] [PubMed]

Opt. Express

Opt. Lett.

Other

S. Manipatruni, Q. Xu, B. Schmidt, J. Shakya, and M. Lipson, “High speed carrier injection 18 Gb/s silicon micro-ring electro-optic modulator,” in Proceedings of LEOS (2007), 537–538.

G. Reed, F. Y. Gardes, G. Z. Mashanovich, Y. Hu, D. Thomson, G. Rasigade, D. Marris-Morini, and L. Vivien, “Recent developments in silicon optical modulators” in Integrated Photonics Research, Silicon and Nanophotonics, OSA Technical Digest (CD) Optical Society of America (2010), paper IWA1.

M. R. Watts, D. C. Trotter, R. W. Young, and A. L. Lentine, “Ultralow power silicon microdisk modulators and switches,” Group IV Photonics, 5th IEEE International Conference on, (2008) doi: 10.1109/GROUP4.2008.4638077 URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4638077&isnumber=4638071 .
[CrossRef]

W. A. Zortman, M. R. Watts, D. C. Trotter, R. W. Young, and A. L. Lentine, “Low-power high-speed silicon microdisk modulators,” Lasers and Electro-Optics (CLEO) and Quantum Electronics and Laser Science Conference (QELS), (2010).

A. V. Krishnamoorthy, R. Ho, X. Zheng, H. Schwetman, J. Lexau, P. Koka, G. Li, I. Shubin, and J. E. Cunningham, “Computer systems based on silicon photonic interconnects,” Proceedings of the IEEE, 97,1337–1361, (2009) doi: 10.1109/JPROC.2009.2020712. URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5071306&isnumber=5075744 .
[CrossRef]

P. M. Kogge, ed., “ExaScale Computing Study: Technology Challenges in Achieving Exascale Systems” Univ. of Notre Dame, CSE Dept. Tech. Report TR-2008–13, (2008).

Y. Berg, O. Mirmotahari, J. G. Lomsdalen, and S. Aunet, “High speed ultra low voltage CMOS inverter” Symposium on VLSI, 2008. ISVLSI '08. IEEE Computer Society Annual, 122–127, (2008) doi: 10.1109/ISVLSI.2008.23.
[CrossRef]

Intel Quick Path Architecture, http://www.intel.com/technology/quickpath/introduction.pdf (2009).

K. Byungsub and V. Stojanovic, “A 4Gb/s/ch 356fJ/b 10mm equalized on-chip interconnect with nonlinear charge-injecting transmit filter and transimpedance receiver in 90nm CMOS” Solid-State Circuits Conference - Digest of Technical Papers, 2009. ISSCC 2009. IEEE International, 66–67,67a, (2009) doi: 10.1109/ISSCC.2009.4977310. URL, http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4977310&isnumber=4977283 .
[CrossRef]

J.-S. Seo, R. Ho, J. Lexau, M. Dayringer, D. Sylvester, and D. Blaauw, “High-bandwidth and low-energy on-chip signaling with adaptive pre-emphasis in 90nm CMOS” Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2010 IEEE International, 182–183, (2010) doi: 10.1109/ISSCC.2010.5433993. URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5433993&isnumber=5433812 .
[CrossRef]

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (8)

Fig. 1
Fig. 1

Circuit schematics of the different signaling regimes proposed for silicon photonic resonant modulators. The first modulators were driven with forward bias and require a high current driver. Next reverse biased devices were introduced that require high voltage drivers to function. AC coupling, taking advantage of both forward and reverse bias operation is very low power, but the circuit implementation is more complex. Either a transistor or diode (or some element) must be placed between the modulator or inverter and ground to maintain the desired bias point. Differential signaling is implemented with inverters and no special drivers. Energies/bit are given for each modulator with selected references to show the effect that signaling has had on this metric. Finally, a possible LVS schematic is shown. Forward bias, reverse bias and AC coupled designs do not have straightforward LVS implementations. Differential signaling is inherently LVS compatible.

Fig. 2
Fig. 2

3.5 micron diameter disk resonator with photograph of the pad layout. Fabrication is done using 250nm thick silicon on 3µm oxide. There is an overclad of 5µm deposited oxide. The P-type ohmic contact is ~100nm thick and the N-type is the full thickness of the silicon and both ohmic regions are 2µm wide. The depletion region is vertical. The 1018 diode doping covers π radians. There is a 350nm gap between the bus and disk. The pad layout shows ground pads all connected to chip and probe ground, yet not connected to the modulator. The P and N pads are signal pads, S and S-bar, and they connect to the modulator as labeled in the disk drawing.

Fig. 3
Fig. 3

Schematic of the pad layout and DC resonances (a) The equivalent circuit diagram shows identical drivers 180° out of phase connected through two 50Ω transmission lines to a probe terminated with 50Ω. The pads have a capacitance of 30fF and the modulator is a 15fF capacitor in series with 1600Ω of resistance. Ground pads run to chip ground and the P and N pads are connected as photographed and drawn in Fig. 1. (b) The DC resonances of the modulator show a Q ~104. For modulation the laser line is put at the 3dB point on the red side of the modulator.

Fig. 4
Fig. 4

DC coupling of the device at three common modes. (a) The common mode of the drive (dotted line) is varied from 250mV to 800mV to 1.2V always resulting in the same differential signal on the device. Eye diagrams for common modes of (b) 0mV, (c) 1.25V and (d) 1.5V at 500mV show the same 5dB extinction verifying the flexibility of the device to DC couple at arbitrary voltage levels. For 400mV the same common modes are shown in (e), (f) and (g) for an extinction of 4dB. The voltage levels and amplitudes in these last three figures show compatibility with both CML and VML signaling.

Fig. 8
Fig. 8

(a) 150mV drive amplitude on both the P (blue) and N (red) silicon contacts on device. The resulting 300mV amplitude signal is shown in green to be only forward biased because of the 500mV bias driven into the N silicon through the use of a bias-T. The forward bias is beneficial in the diode sub-threshold region because the carrier extraction is driven by depletion region expansion instead of carrier lifetime enabling the (b) 10Gbps eye diagram shown on the right with 3dB extinction.

Fig. 6
Fig. 6

(a) 500mV drive amplitude on both the P (blue) and N (red) silicon contacts on device. The resulting 1V amplitude signal is shown in green to be slightly forward biased because of the 300mV positive bias driven into the N silicon through the use of a bias-T. The slight forward bias is beneficial because the depletion region expands according to the square root of the voltage applied. (b) The corresponding 10Gbps eye diagram shows 5dB extinction.

Fig. 5
Fig. 5

(a) 750mV drive amplitude on both the P (blue) and N (red) silicon contacts on device. The resulting 1.5V amplitude signal is shown in green to be slightly reversed biased because of the 300mV negative bias driven into the N silicon through the use of a bias-T. (b) The corresponding 10Gbps eye diagram shows 6dB extinction.

Fig. 7
Fig. 7

(a) 300mV drive amplitude on both the P (blue) and N (red) silicon contacts on device. The resulting 600mV amplitude signal is shown in green to be only forward biased because of the 400mV bias driven into the N silicon through the use of a bias-T. The forward bias is beneficial in the diode sub-threshold region because the carrier extraction is driven by depletion region expansion instead of carrier lifetime enabling the (b) 10Gbps eye diagram shown on the right with 4dB extinction.

Metrics