Browsing by Author "Chao, Rui Lin"

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Forward bias operation of silicon photonic Mach Zehnder modulators for RF applications
(2017-09-18)
Chao, Rui Lin
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Shi, Jin Wei
;
Jain, Aditya
;
Hirokawa, Takako
;
Khope, Akhilesh S. P.
In this paper, we demonstrate that forward bias (+ 0.9V) of a high-speed silicon (Si) optical Mach-Zehnder Modulator (MZM) increases the radio-frequency (RF) link gain by 30 dB when compared to reverse bias operation (-8V). RF applications require tunable, narrowband electro-optic conversion with high gain to mitigate noise of the optical receiver and realize high RF spur-free dynamic range. Compared to reverse bias, the forward bias gain rolls off more rapidly but offers higher RF link gain improvement of more than 13.2 dB at 20 GHz. Furthermore, forward bias is shown to result in comparable spurious-free dynamic range (SFDR: 104.5 dB. Hz(2/3)). We demonstrate through an analytical dc transfer curve the existence of simultaneous high gain and OIP3 and verify the theoretical results with measurement under forward bias at a bias point of around + 0.9 V. (C)2017 Optical Society of America
Forward Bias Optimization of a Silicon Photonic Modulator for Analog Application
(2017-01-01)
Jain, Aditya
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Chao, Rui Lin
;
Shi, Jin Wei
;
Schow, Clint
;
Bowers, J. E.
Despite the high phase non-linearity of a Silicon Mach-Zehnder Modulator in forward bias, we demonstrate that high third order spur-free dynamic range similar to 102.8 dB. Hz(2/3) can be obtained by optimizing the D.C. bias operating point at 1 GHz.
Three-Port Optical Phase-Shifters and Modulators With Ultra-High Modulation Efficiency, Positive RF-Linking Gain, and Low Residual Amplitude Modulation
(2020-01-01)
Chao, Rui Lin
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Ahmad, Zohauddin
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Chen, Jyehong
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Lai, Yinchieh
;
Shi, Jin-Wei
A three-port optical phase-shifter and Mach-Zehnder modulator (MZM) based on PNP-type bipolar junction transistor (BJT) is demonstrated. Significant plasma (injected carrier) induced changes of the refractive index for the optical waveguide become possible with an extremely small driving-voltage and a compact device size during operation of this BJT between the saturation and forward active modes. Devices with a standard MZM structure and a small foot-print (0.5 mm) exhibit a moderate optical insertion loss (2 dB), extremely small (0.18V) and (0.21mW), fast rise/fall time (& x007E; 1ns), and a residue-amplitude-modulation (RAM) as small as 0.18 dB. Furthermore, thanks to the ultra-high modulation efficiency characteristic of our device, a & x002B;4.0 dB net RF-linking gain can be obtained under dynamic operation. Compared to 2-port (base-collector) forward bias operation, under three-port operation, the extra bias current from the base-emitter junction provides a lower (0.18 vs. 0.22 V), a smaller RAM (0.18 vs. 0.6 dB), and a larger RF-linking gain (& x002B;4 vs. & x2212;3.2 dB). The superior performances of the three-port to two-port operations can be attributed to the additional forward bias B-E junction being able to provide more injected carriers to induce stronger plasma effects for optical phase-shifting.