{"id":1635,"date":"2013-07-25T18:30:30","date_gmt":"2013-07-25T18:30:30","guid":{"rendered":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/?p=1635"},"modified":"2013-08-06T19:52:44","modified_gmt":"2013-08-06T19:52:44","slug":"vertical-junction-silicon-microdisk-modulators-at-25gbs","status":"publish","type":"post","link":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/vertical-junction-silicon-microdisk-modulators-at-25gbs\/","title":{"rendered":"Vertical Junction Silicon Microdisk Modulators at 25Gb\/s"},"content":{"rendered":"

High-performance computing systems require high bandwidth, low power, and scalable optical interconnects to maintain balanced communications in future exascale machines. Low-power, low-voltage, high-speed, and compact CMOS-compatible silicon electro-optic modulators are key enablers for next generation optical interconnects. Silicon modulators based on the free-carrier effect in silicon achieve high-speed modulation by injecting or depleting charge, inducing a frequency shift in a Mach-Zehnder interferometer or resonant device that translates the resultant frequency shift into an amplitude response. Resonant modulators confine light in compact high-Q devices, enhancing the interaction of the light with the change in charge distribution. Compact resonant devices also minimize the device capacitance, enabling high-speed and low power modulators. In previous record-setting demonstrations, vertical p-n<\/i> junction devices have achieved error-free modulation up to 12.5Gb\/s with only a 1V drive and while consuming only 3fJ\/bit[1<\/a>]<\/sup>.<\/p>\n

In our work[2<\/a>]<\/sup>, we experimentally demonstrate the first vertical junction silicon microdisk modulator (Figure 1a-b) to achieve open eye-diagrams at a data rate of 25Gb\/s (Figure 1d) and error-free operation up to 20Gb\/s. A circular overlapping p+ and n+ doping profile within circularly contacted microdisk modulators (Figure 1a-b) reduce the device resistance and enable high-speed operation while maintaining a hard outer wall for maximizing the optical confinement. Frequency shifts and spectral response is shown in Figure 1c. The device represents the smallest silicon modulator to run at 25Gb\/s and achieves the lowest reported power penalty compared to a commercial LiNbO3<\/sub> modulator [2], important for the overall power budget in a microphotonic link.<\/p>\n

\"Figure<\/a>

Figure 1: a) Top-view of the 6-\u00b5m-diameter microdisk modulator, which utilizes circular inner contacts. b) 2D cross-section showing the doping profile with p-n vertical junction, p+and n+ overlapping regions. c) Spectral response of the microdisk modulator with respect to voltage dropped and current passing through the microdisk modulator. d) High-speed measured optical eye diagrams at 10-, 15-, 20-, and 25-Gb\/s data rates of the microdisk modulator, driven by AC coupled 1.2Vpp. The eye diagrams are shown with the true zero (gray line) at each data rate.<\/p><\/div>\n

  1. M. R. Watts, W. A. Zortman, D. C. Trotter, R. W. Young, and A. L. Lentine, \u201cVertical junction silicon microdisk modulators and switches,\u201d Opt. Exp., <\/i>vol. 19, no. 22, pp. 21989\u201322003 2011. [↩<\/a>]<\/li>
  2. E. Timurdogan, C. M. Sorace-Agaskar, A. Biberman, and M. R. Watts, \u201cVertical Junction Silicon Microdisk Modulators at 25Gb\/s,\u201d in Proc. OFC\/NFOEC<\/i>, paper OTh3H.2 2013. [↩<\/a>]<\/li><\/ol>","protected":false},"excerpt":{"rendered":"

    High-performance computing systems require high bandwidth, low power, and scalable optical interconnects to maintain balanced communications in future exascale machines….<\/p>\n","protected":false},"author":370,"featured_media":2409,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[6083,5532],"tags":[12761,11652],"_links":{"self":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/posts\/1635"}],"collection":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/users\/370"}],"replies":[{"embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/comments?post=1635"}],"version-history":[{"count":5,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/posts\/1635\/revisions"}],"predecessor-version":[{"id":2410,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/posts\/1635\/revisions\/2410"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/media\/2409"}],"wp:attachment":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/media?parent=1635"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/categories?post=1635"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/tags?post=1635"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}