Numerical Modeling and Analysis for High-Efficiency Carrier-Depletion Silicon Rib-Waveguide Phase Shifters

Png, Ching Eng; Sun, Mengjia; Lim, Soon Thor; Ang, Thomas Y. L.; Ogawa, Kensuke

doi:10.1109/jstqe.2016.2564648

Cited by 13 publications

(7 citation statements)

References 28 publications

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“…Carriers consisting of electrons from the N-doped region and holes from the P-type region transport in the depletion region with drift velocity to reach the equilibrium condition of carrier distribution for change in reverse bias voltage. The transit time of carriers across the depletion region is evaluated computationally in TCAD simulation by solving self-consistently Poisson equation of carrier distribution and drift-diffusion current equations of electrons and holes, respectively [28]:…”

Section: Transit Timementioning

confidence: 99%

Increase in Modulation Speed of Silicon Photonics Modulator with Quantum-Well Slab Wings: New Insights from a Numerical Study

Ogawa

2024

Photonics

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A Silicon Photonics modulator is a high-speed photonic integrated circuit for optical data transmission in high-capacity optical networks. Silicon Photonics modulators in the configuration of a Mach–Zehnder interferometer, in which a PN-junction rib-waveguide phase shifter is inserted in each arm of the interferometer, are studied in this paper because of their superior performance of high-quality optical data generation in a wide range of spectral bands and their simplicity in fabrication processes suitable to production in foundries. Design, fabrication, and fundamental characteristics of Silicon Photonics Mach–Zehnder modulators are reviewed as an introduction to these high-speed PICs on the Silicon Photonics platform. Modulation speed, or modulation bandwidth, is a key performance item, as well as optical loss, in the application to high-speed optical transmitters. Limiting factors on modulation speed are addressed in equations. Electrical resistance–capacitance coupling, which causes optical modulation bandwidth–optical loss trade-off, is the most challenging limiting factor that limits high-speed modulation. Expansion of modulation bandwidth is not possible without increasing optical loss in the conventional approaches. A new idea including quantum-mechanical effect in the design of Silicon Photonics modulators is proposed and proved in computational analysis to resolve the bandwidth loss trade-off. By adding high-mobility quantum-well overlayers to the side slab wings of the rib-waveguide phase shifter, the modulation bandwidth is doubled without increasing optical loss to achieve a 200 Gbaud modulation rate.

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Section: Transit Timementioning

confidence: 99%

Increase in Modulation Speed of Silicon Photonics Modulator with Quantum-Well Slab Wings: New Insights from a Numerical Study

Ogawa

2024

Photonics

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“…2.5×10 -5 and the imaginary part is ΔI 1 (neff) = 6×10 -6 , ΔI 2 (neff) = 5×10 -8 . Therefore, according to formula (6), to realize the movement of π phase, the length of the phase shifter needs to be at least L = 12.03 mm. Compared with applying a reverse voltage, applying a forward voltage has a more obvious phase shift effect.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Especially in the structural design of optical devices, the deviation of the processing size accuracy will cause the optical signal to deviate during the propagation process, particularly for some A c c e p t e d M a n u s c r i p t devices that strictly require the interference of the optical signal, the phase shifter is extremely important. There are two major types of phase shifters based on the free carrier dispersion effect(4): one is carrier injection (5); the other is carrier depletion (6). The carrier injection phase shifter mainly injects carriers into the waveguide through the diffusion of carriers.…”

Section: Introductionmentioning

confidence: 99%

Design and optimization of diamond mid-infrared phase shifter

Chen

Zhi

et al. 2021

Functional Diamond

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Herein, the mid-infrared (7.7-13.7 μm) diamond-based phase shifter was designed and optimized by finite-element analysis. The ridge-shaped diamond waveguide is designed and doped to form the internal p-n structure, and the internal carrier distribution is changed by applying forward and reverse voltages to change the effective refractive index to achieve the effect of π-phase shift. The results show that when p-doping concentration is 4×10 17 cm-3 and n doping concentration is 1×10 18 cm-3 , upon the reverse voltage (8 V) is applied, the change of the real part of effective refractive index (ΔR) is 1.6×10-5 , and the length of the phase shifter (L) required to realize the π-phase shift is 241 mm; upon the forward voltage (-8 V) is applied, ΔR increases to 3.2×10-4 , and the length of the phase shifter required is shortened to 12.03 mm. Such a short length is relatively easy in industrial production. In order to make the refractive index distribution more uniform, the carrier concentration has been optimized as 1×10 17 cm-3 for p-type and 4×10 17 cm-3 for n-type, respectively.

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“…The resulting change in the real part of the refractive index is used to change the phase of light while the imaginary part corresponds to a change in the absorption coefficient. The change in refractive index and absorption coefficient at 1550 nm for silicon is given in [10] which has been modified for the proposed structure by using the obtained strained layer parameters as given below:…”

Section: Phase Shifter Performance Analysismentioning

confidence: 99%

Design and Analysis of a Graded-Index Strained Si<inline-formula> <tex-math notation="LaTeX">$_{1-x}$ </tex-math> </inline-formula>Ge<inline-formula> <tex-math notation="LaTeX">$_x$</tex-math> </inline-formula> Optical PN Phase Shifter

Mishra

Sonkar

2018

IEEE Photonics J.

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In this paper, a graded-index strained Si 1−x Ge x optical PN phase shifter with multiple strained layers has been proposed for high speed data modulation at 1550 nm with low device footprint. The quasi-vectorial finite difference method, non-local empirical pseudopotential method and the Payne-Lacey model has been used to analyze the proposed device. A phase shift of 122 • /mm, V π L π of 0.74 V.cm, and insertion loss of 4 dB at 5 V reverse bias with a 3-dB modulation bandwidth of 27.5 GHz has been obtained for a 500 nm × 250 nm cross-section rib waveguide with 50 nm slab. A 15 • /mm increase in phase shift and 0.08 V.cm decrease in V π L π has been observed when the junction is shifted by 60 nm towards the N side.

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Numerical Modeling and Analysis for High-Efficiency Carrier-Depletion Silicon Rib-Waveguide Phase Shifters

Cited by 13 publications

References 28 publications

Increase in Modulation Speed of Silicon Photonics Modulator with Quantum-Well Slab Wings: New Insights from a Numerical Study

Increase in Modulation Speed of Silicon Photonics Modulator with Quantum-Well Slab Wings: New Insights from a Numerical Study

Design and optimization of diamond mid-infrared phase shifter

Design and Analysis of a Graded-Index Strained Si<inline-formula> <tex-math notation="LaTeX">$_{1-x}$ </tex-math> </inline-formula>Ge<inline-formula> <tex-math notation="LaTeX">$_x$</tex-math> </inline-formula> Optical PN Phase Shifter

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