Abstract
We analyze energy consumption in optical modulators operated in depletion and intended for low-power interconnect applications. We include dynamic dissipation from charging modulator capacitance and net energy consumption from absorption and photocurrent, both in reverse and small forward bias. We show that dynamic dissipation can be independent of static bias, though only with specific kinds of bias circuits. We derive simple expressions for the effects of photocurrent on energy consumption, valid in both reverse and small forward bias. Though electroabsorption modulators with large reverse bias have substantial energy penalties from photocurrent dissipation, we argue that modulator diodes with thin depletion regions and operating in small reverse and/or forward bias could have little or no such photocurrent energy penalty, even conceivably being more energy-efficient than an ideal loss-less modulator.
Highlights
Because of the quantum nature of optical detection [1], optics could reduce the energy for transmitting information even at short distances inside computers and information switching and processing machines [1,2,3]
/ e) ), so any photocurrent in this state is fed back into the bias supply. Such a scheme is conceivably viable for Ge quantum well modulators driven from low voltage CMOS
Optical modulators are attractive compared to lasers for low-energy dense optical interconnects because they offer threshold-less operation and easier integration with Si
Summary
Because of the quantum nature of optical detection [1], optics could reduce the energy for transmitting information even at short distances inside computers and information switching and processing machines [1,2,3]. Because the absorption edge can remain quite abrupt even with large bias [23, 36], such bias allows the modulator’s operating wavelength to be voltage-tuned while still allowing low drive swing [19, 23, 36] Such static bias can, lead to additional dissipation from photocurrent and to some consequences for the dynamic dissipation of the modulator that we discuss below. Fixed capacitance is a substantial approximation for some silicon carrier depletion modulators that may not use p-i-n diodes, but our model should allow reasonable comparisons This model covers electrorefractive (electro-optic) devices in the form of either biased insulating materials, such as electro-optic polymers [26], or diodes; presumably these would have little if any photocurrent. After summarizing dissipation results, we discuss implications for device design
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
