Browsing by Author "Chen, Xin-Nan"

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850 nm Vertical-Cavity Surface-Emitting Laser Arrays With Enhanced High-Speed Transmission Performance Over a Standard Multimode Fiber
(2017-08-01)
Yen, Jia-Liang
;
Chen, Xin-Nan
;
Chi, Kai-Lun
;
Chen, Jason
;
Shi, Jin-Wei
The functionality of novel parallel and series highspeed vertical-cavity surface-emitting laser (VCSEL) arrays, which can greatly relax the tradeoff between output power and modulation speed, is demonstrated. Both types of array structure allow improvement in the output power with no degradation in their maximum modulation speed as compared to a single reference unit. The observed invariant electrical-optical bandwidth shown for these array structures is mainly due to the effective reduction of the differential resistance and parasitic capacitance, arising from the Zn-diffusion and oxide-relief apertures fabricated in the VCSEL unit. This in turn minimizes the degradation in the RC-limited bandwidth with the VCSEL arrays. Furthermore, the dense packing of single VCSELs, with Zn-diffusion apertures for optical mode control, minimizes the coupling loss between the output from the array into a standard multimode fiber (MMF). Compared with the single VCSEL unit, the parallel VCSEL array shows a significant enhancement in transmission performance over a standard OM4 MMF, which includes a larger eye margin, a higher signal-to-noise ratio, as well as a higher error-free data rate (48 versus 44 Gbit/sec). The device modeling technique is used to perform device analysis. From the results we can conclude that the improvement with the parallel array is because the value of the internal impedance is closer to the 50-Omega signal source, which minimizes the microwave reflection induced timing jitter in the eye-patterns.
850-nm VCSELs With p-Type delta-Doping in the Active Layers for Improved High-Speed and High-Temperature Performance
(2016-11)
Chi, Kai-Lun
;
Hsieh, Dan-Hua
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Yen, Jia-Liang
;
Chen, Xin-Nan
;
Chen, Jason (Jyehong)
In this paper, we study the influence of p-type modulation doping on the dynamic/static performance of highspeed 850-nm VCSELs with highly strained multiple quantum wells. The studied device structure has a 3/2 lambda asymmetric cavity design, which can let the internal transit time of injected carriers be as short as that of 1/2 lambda cavity design and further improve its performance in terms of speed and output power for high single-mode operation. Our proposed VCSEL structure with p-type doping shows superior modulation speed with an output power comparable with that of the un-doped reference device under room temperature operation. Furthermore, when the operating temperature reaches 85 degrees C, there is a significant improvement in both the modulation speed and maximum power of the p-doped structures. According to our simulation, this can be attributed to the change in the quasi-Fermi levels of the injected carriers after the addition of p-doping in the active layers, which minimizes the electron leakage under high-temperature operation.
Bandwidth Enhancement Equalization Enabling a 40-Gbps PAM4 Transmission via a 9.5-GHz Photoreceiver
(2016)
Liu, Jun-Jie
;
Wei, Chia-Chien
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Tzu, Ta-Ching
;
Chuang, Chun-Yen
;
Chi, Kai-Lun
We demonstrate a 40-Gbps PAM4 optical system by employing a photoreceiver with bandwidth of only 9.5 GHz. Following 100 m multimode fiber, the BER of l. 8 x 10(-4) and 1.2 x 10(-4) after FFE and DFE equalizations are successfully achieved
High Bit-Rate Distance Product of 128 Gbps.km 4-PAM Transmission over 2-km 0M4 fiber Using an 850-nm VCSEL and a Volterra Nonlinear Equalizer
(2017-01-01)
Liu, Jun-Jie
;
Chi, Kai-Lun
;
Wei, Chia-Chien
;
Lin, Tien-Chien
;
Chuang, Chun-Yen
We successfully demonstrate a 64-Gbps 4-PAM transmission over 2-kin OM4 fiber incorporating a Volterra equalizer with BER of 6.5 x10(-5). Record high bit-rate distance product of 128 Gbps.km is confirmed for optical-interconnect applications.
Nonlinear Compensation of 850 nm VCSEL with Discrete Multi-Tone Modulation Employing a Volterra-Wiener Filter
(2016)
Tzu, Ta-Ching
;
Wei, Chia-Chien
;
Liu, Jun-Jie
;
Chang, Chun-Yen
;
Chi, Kai-Lun
A DMT transmission with 32% and 21.2% data rate improvement by nonlinear Volterra-Wiener compensation respectively for 68.94Gb/s OBTB and 58.39Gb/s over 105m is demonstrated by a 850nm VCSEL with short (lambda/2) cavity and mode controlled.
Single-Mode 850-nm VCSELs for 54-Gb/s ON-OFF Keying Transmission Over 1-km Multi-Mode Fiber
(2016-06-15)
Chi, Kai-Lun
;
Shi, Yi-Xuan
;
Chen, Xin-Nan
;
Chen, Jason (Jyehong)
;
Yang, Ying-Jay
By combing Zn-diffusion and oxide-relief apertures with strong detuning (>20 nm) in our demonstrated short-cavity (lambda/2) 850-nm vertical-cavity surface-emitting lasers (VCSELs), wide electrical-to-optical bandwidth (29-24 GHz), low-differential resistance (similar to 100 Omega), and (quasi) single-mode (SM) with reasonable output power (similar to 1.4 mW) performances can be simultaneously achieved. Error-free ON-OFF keying transmission at 54-Gb/s data rate through 1-km OM4 multi-mode fiber can be achieved by using highly SM device with forward error correction and decision feedback equalization techniques. As compared with the reference device with a larger oxide-relief aperture and a multi-mode performance, the SM device exhibits lower bit-error rate (1x10(-5) versus 1x10(-2)) at 54 Gb/s. This result indicates that modal dispersion plays more important role in transmission than that of output power does. We benchmark these results to an industrial 50-Gb/s SM VCSEL. It shows a higher bit-error-rate value similar to 3.5x10(-3) versus similar to 1.4x10(-4) under the same received optical power.
Strong Enhancements in Output Power and High-Speed Data Transmission Performances by Using Parallel Oxide-Relief/Zn-Diffusion 850 nm VCSELs
(2016)
Chi, Kai-Lun
;
Chen, Xin-Nan
;
Chen, Jye-Hong
;
Bowers, J. E.
;
Yang, Ying-Jay
By using parallel two high-speed VCSELs, double increase in maximum output power (4 vs. 8mW), negligible degradation in 3-dB electrical-to-optical bandwidth (similar to 25 GHz), and strong enhancement in 46 Gbit/sec data transmission through OM4 MMF is achieved compared with those of single reference.
Strong Enhancements in Static/Dynamic Performances of High-Speed 850 nm Vertical-Cavity Surface-Emitting Lasers with P-type delta-Doping in Highly Strained Active Layers
(2016)
Chi, Kai-Lun
;
Chen, Xin-Nan
;
Yen, Jia-Liang
;
Lin, Wei
;
Chiu, Shi-Wei
By using p-type modulation doping in the highly strained MQWs of high-speed 850 nm VCSELs, significant enhancements in speed, slope efficiency, and maximum power have been simultaneously achieved as compared to those of un-doped references