Exploiting CMOS Manufacturing to Reduce Tuning Requirements for Resonant Optical Devices

Krishnamoorthy, Ashok V.; Zheng, Xuezhe; Li, Guoliang; Yao, Jin; Pinguet, Thierry; Mekis, Attila; Thacker, Hiren; Shubin, Ivan; Luo, Ying; Raj, Kannan; Cunningham, J. E.

doi:10.1109/jphot.2011.2140367

Cited by 137 publications

(63 citation statements)

References 36 publications

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“…However, current system designs suggest that such large tuning ranges are unnecessary. Advances in silicon photonic fabrication have been able to control wafer and etch tolerances to produce relatively evenly spaced WDM microring arrays [74]. In evenly channel-spaced WDM microring arrays, no microring will need to be initially tuned beyond one channel spacing length.…”

Section: Resultsmentioning

confidence: 99%

Resolving the thermal challenges for silicon microring resonator devices

2014

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Silicon microring resonators have been hailed for their potential use in next-generation optical interconnects. However, the functionality of silicon microring based devices suffer from susceptibility to thermal fluctuations that is often overlooked in their demonstrated results, but must be resolved for their future implementation in microelectronic applications. We survey the emerging efforts that have been put forth to resolve these thermal susceptibilities and provide a comprehensive discussion of their advantages and disadvantages.Keywords: integrated photonics; microring resonators; optical interconnects; silicon photonics. The growing bandwidth needs within data applications have motivated the replacement of traditionally electronic links with optical links for information networks as diverse as data centers, supercomputers, and fiber-optic access networks [1,2]. Applications such as these stress the traditional portfolio of optical components, rebalancing the emphasis from expensive high-performance components towards low-cost high-volume components that can be closely integrated with electronics. With these considerations in mind, the silicon photonics platform has received wide attention for its ability to deliver the necessary bandwidth required at an economy-of-scale that will be enabled by its compatibility with CMOS fabrication processes [3].Within the silicon photonic platform, traditional optical components such as low-loss waveguides [4], lowloss waveguide crossings [5], high-speed mach-zhender modulators (MZM) [6], arrayed waveguide-gratings [7], and efficient photodetectors [8,9] have been demonstrated. Leveraging the high index contrast between silicon and silicon-on-insulator, the aforementioned components have been shown with much smaller footprints than their counterparts in more conventional optical platforms. For active devices, these smaller footprints directly translate to higher energy-efficiencies.In addition to providing these improvements in footprint and energy-efficiency for traditional devices, the high-index contrast present in the silicon photonic platform enables the effective use of microring-based devices. A microring is a traveling wave resonator consisting of a ring structure side-coupled to a bus waveguide. While they have also been demonstrated in other material platforms, the high-index contrast of silicon and silicon-oninsulator has allowed them to be manifested as small as 1.5 µm in radius [10], and when used in conjunction with the free-carrier dispersion effect [11], well into Ghz-rate bandwidth. Figure 1A illustrates the optical resonance of the microring and its shift with applied electrical bias [12]. In their most basic capacity they can serve as effective filters [13], switches [14,15], and modulators [16,17]. Additionally, microrings can be cascaded along the same waveguide bus, with each microring being offset to provide functionality for a specific wavelength. In this manner, the microring lends itself naturally for wavelength-divisionmultiplexed ...

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Section: Resultsmentioning

confidence: 99%

Resolving the thermal challenges for silicon microring resonator devices

2014

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“…This is far from the 2015 energy target for tunable WDM filters of 30 fJ/bit [2] or reported values of 15 fJ/bit [11] using under-etched waveguides and flexible wavelength registration. Another way to improve the power consumption could come from (1) fabrication, where a better control over the silicon waveguide thickness could lower the maximum tuning range required [12], (2) from design, by using designs with larger FSR and thus increasing the wavelength shift for given power consumption or (3) by an increased bitrate.…”

Section: B Thermal Tuningmentioning

confidence: 83%

Fabrication-Tolerant Four-Channel Wavelength-Division-Multiplexing Filter Based on Collectively Tuned Si Microrings

Heyn

Coster

Verheyen

et al. 2013

J. Lightwave Technol.

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Abstract-We demonstrate a robust, compact and low-loss four-channel wavelength-division multiplexing (WDM) filter based on cascaded double-ring resonators (2RR) in silicon. The flat-top channel response obtained by the second-order filter design is exploited to compensate for the detrimental effects of local fabrication variations and their associated phase errors on the ring-based filter response. Full wafer-scale characterization of a cascaded, four-channel 2RR filter with channel spacing of 300 GHz shows an average worst-case insertion loss below 1.5 dB and an average worst-case crosstalk below 18 dB across the wafer, representing a substantial improvement over a first-order based ring (1RR) design. The robust 2RR filter design enables the use of a simple collective thermal tuning mechanism to compensate for global fabrication variations as well as for global temperature fluctuations of the WDM filter, the WDM laser source, or both. Highly uniform collective heating is demonstrated using integrated doped silicon heaters. The compact filter footprint of less than per channel enables straightforward scaling of the WDM channel count to 8 channels and beyond. Such low-loss collectively tuned ring-based WDM filters can prove beneficial in scaling the bandwidth density of chip-level silicon optical interconnects.Index Terms-Design for manufacturing, microring resonators, silicon-on-Insulator (SOI), wavelength-division multiplexing.

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“…As no mode conversion and coupling occur in the PRS for the TE 0 mode input, the performance metrics remain stable with the above variation for the TE 0 mode input through our simulation. Manufacturing deviations with a top silicon thickness variation of AE5 nm and linewidth variations <1% are demonstrated in silicon photonic platforms [11,12] , which are smaller than the fabrication tolerances of the design. Due to the adiabatic conversion and coupling of modes in the bi-level taper and counter-tapered coupler, the width, thickness, or wavelength variation only lead to the position shift of the mode hybridizations and phase-matching points and will not affect the PRS performance seriously.…”

mentioning

confidence: 95%

“…The fabrication process sensitivity of the device is also analyzed, showing a large fabrication tolerance with a waveguide width variation of AE40 nm and top silicon thickness or slab height variation of AE10 nm for the entire operation waveband. Considering the manufacturing deviations in industrial silicon photonic foundries that have a top silicon thickness variation of AE5 nm and linewidth variations <1% [11,12] , this proposed device is quite fabrication tolerant. With such a broad operating bandwidth and a robust performance, this device offers great potential in silicon photonic systems, especially in applications requiring large bandwidths, such as WDM PONs for FTTH.…”

mentioning

confidence: 99%

Design of an ultra-broadband and fabrication-tolerant silicon polarization rotator splitter with SiO2 top cladding

Chen

Qiu²,

Sheng

et al. 2016

中国光学快报

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An ultra-broadband and fabrication-tolerant silicon polarization rotator splitter is proposed in this Letter. Benefitting from the broadband and low-loss characteristics of the bi-level taper and counter-tapered coupler, the designed device has a simulated insertion loss and crosstalk of less than 0.2 and −15 dB in the waveband from 1290 to 1610 nm. These characteristics make it valuable in applications with large bandwidth requirements, such as full-grid Coarse wavelength division multiplexer (CWDM) and diplexer/triplexer fiber-to-the-home systems. The fabrication tolerance of the design is also analyzed, showing that the device performance is quite stable with normal manufacturing errors in silicon photonics foundries.

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Exploiting CMOS Manufacturing to Reduce Tuning Requirements for Resonant Optical Devices

Cited by 137 publications

References 36 publications

Resolving the thermal challenges for silicon microring resonator devices

Resolving the thermal challenges for silicon microring resonator devices

Fabrication-Tolerant Four-Channel Wavelength-Division-Multiplexing Filter Based on Collectively Tuned Si Microrings

Design of an ultra-broadband and fabrication-tolerant silicon polarization rotator splitter with SiO2 top cladding

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