Emerging VCSEL technologies at Finisar

Gazula, D.; Guenter, James K.; Johnson, R.H.; Landry, Gary D.; MacInnes, Andrew N.; Park, G.; Wade, J.K.; Biard, J.R.; Tatum, Jim A.

doi:10.1117/12.841012

Cited by 3 publications

(5 citation statements)

References 3 publications

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“…While these modes are orthogonal to each other, their beating (mediated by spatial hole burning in the quantum wells) is different from zero and results in undesired peaks in the relative intensity noise (RIN) spectrum with consequent increase of the RIN integrated over the receiver bandwidth, which is detrimental for error-free transmission. In this context, a design of particular interest relies on an elliptical oxide aperture [2]- [4]: by breaking the quasi-degeneracy of the transverse modes, this configuration pushes their frequency separation beyond the receiver bandwidth while also allowing for high emitted power. However, as the required bandwidth will increased due to the demand for increasingly higher data rates, the problem of mastering the RIN characteristics and finding a methodology for optimizing the VCSEL design with low RIN over a wide bandwidth is bound to re-emerge.…”

Section: Introductionmentioning

confidence: 99%

CW Emission and Self-Pulsing in a III-V/SiN Hybrid Laser With Narrow Band Mirror

Rimoldi

Columbo

Bovington³

et al. 2022

IEEE Photonics J.

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We report on how external cavity III-V/SiN hybrid lasers operate in regimes of ultra-damped relaxation oscillations or in CW unstable dynamical regimes (self-pulsing or approaching turbulence) as a consequence of mirror dispersion, non-zero linewidth enhancement factor, and four-wave mixing in the gain medium. The impact of the dispersive mirror bandwidth and different mirror effective lengths on the laser tolerance to external optical feedback is also discussed.

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Section: Introductionmentioning

confidence: 99%

CW Emission and Self-Pulsing in a III-V/SiN Hybrid Laser With Narrow Band Mirror

Rimoldi

Columbo

Bovington³

et al. 2022

IEEE Photonics J.

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“…As shown in Figure 5a, the model contains simple lumped components for bonding pad C PAD (68.3 pF), distributed resistance components R P1 (215Ω), R P2 (147Ω), and R L (1690Ω) for mirror, and combined junction and oxide capacitance C JOX (34 pF). This simplified lumped model has been verified from DC to high frequency (25 GHz) to match well with measured responses from the physical VCSEL laser [29]. In our simulation, a small CMOS driver with transistor sizes of 10 µm was used to turn on and off the laser block.…”

Section: Feasibility Studymentioning

confidence: 72%

“…To fully assess the lower possible boundaries of the transceiver timing specifications, the only remaining component in our device-level feasibility study, we derived a SPICEbased analog simulation model for the laser driver depicted in Figure 5a. In this configuration, we considered the RLC electrical circuit equivalent for the VCSEL as provided by Finisar in [29].…”

Section: Feasibility Studymentioning

confidence: 99%

“…2) Electronic Circuit Simulation: We created a spice simulation in a 45 nm CMOS technology following the specification provided from VCSEL laser model [29]. As shown in Figure 5a, the model contains simple lumped components for bonding pad C PAD (68.3 pF), distributed resistance components R P1 (215Ω), R P2 (147Ω), and R L (1690Ω) for mirror, and combined junction and oxide capacitance C JOX (34 pF).…”

Section: Feasibility Studymentioning

confidence: 99%

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Energy-Proportional Data Center Network Architecture Through OS, Switch and Laser Co-design

Han¹,

Terzenidis²,

Syrivelis³

et al. 2021

Preprint

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Optical interconnects are already the dominant technology in large-scale data center networks. However, the high optical loss of many optical components coupled with the low efficiency of laser sources result in high aggregate power requirements for the thousands of optical transceivers used by these networks. As optical interconnects stay always on even as traffic demands ebb and flow, most of this power is wasted. We present LC DC , a data center network system architecture in which the operating system, the switch, and the optical components are co-designed to achieve energy proportionality.LC DC capitalizes on the path divergence of data center networks to turn on and off redundant paths according to traffic demand, while maintaining full connectivity. Turning off redundant paths allows the optical transceivers and their electronic drivers to power down and save energy. Maintaining full connectivity hides the laser turn-on delay. At the node layer, intercepting send requests within the OS allows for the NIC's laser turn-on delay to be fully overlapped with TCP/IP packet processing, and thus egress links can remain powered off until needed with zero performance penalty.We demonstrate the feasibility of LC DC by i) implementing the necessary modifications in the Linux kernel and device drivers, ii) implementing a 10 Gbit/s FPGA switch, and iii) performing physical experiments with optical devices and circuit simulations. Our results on university data center traces and models of Facebook and Microsoft data center traffic show that LC DC saves on average 60% of the optical transceivers power (68% max) at the cost of 6% higher packet delay.

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“…In particular, it can be shown that adopting an elliptical oxide aperture breaks the degeneracy of transverse modes and pushes their frequency separation beyond the expected receiver bandwidth. 4,5 While this efficiently solves the problem at hand, the VCSELs and consequent optical transceivers fabricated today will not necessarily be able to cope with future generation receivers with bandwidths > 50 GHz, as expected due to the demand for increasingly higher data rates. Therefore, a more in-depth theoretical and numerical study able to address the physical cause behind such noise degradation is mandatory in order to be able to guarantee a lasting datacom infrastructure.…”

Section: Introductionmentioning

confidence: 99%

Dynamical analysis of multimode VCSELs with elliptical oxide aperture

Rimoldi,

Columbo,

Tibaldi

et al. 2024

Vertical-Cavity Surface-Emitting Lasers XXVIII

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We study the dynamics of a multimode VCSEL with an elliptical oxide aperture for datacom applications. We simulate the laser dynamics through a set of coupled rate equations for the modal components of the electric field and the carrier density, accounting for coherent mode mixing and spatial hole burning. Our simulations show what are the relevant frequency detuning configurations to control in order to improve noise performance. Simulations with NRZ PRBS performed in order to explore the applications of these devices in short-reach data transmission show potentially reachable transmission speeds of 65 Gbit/s.

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Emerging VCSEL technologies at Finisar

Cited by 3 publications

References 3 publications

CW Emission and Self-Pulsing in a III-V/SiN Hybrid Laser With Narrow Band Mirror

CW Emission and Self-Pulsing in a III-V/SiN Hybrid Laser With Narrow Band Mirror

Energy-Proportional Data Center Network Architecture Through OS, Switch and Laser Co-design

Dynamical analysis of multimode VCSELs with elliptical oxide aperture

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