Transition from on-off keying to 4-level pulse amplitude modulation (PAM) in VCSEL based optical interconnects allows for an increase of data rates, at the cost of 4.8 dB sensitivity penalty. The resulting strained link budget creates a need for accurate VCSEL models for driver integrated circuit (IC) design and system level simulations. Rate equation based equivalent circuit models are convenient for the IC design, but system level analysis requires computationally efficient closed form behavioral models based Volterra series and neural networks. In this paper we present and compare these models.

A full 2-D simulation was performed to investigate electrical derivative characteristics of 1.3μm AlGaInAs/InP buried-heterostructure semiconductor lasers with different current leakage paths and to explain their physical root causes. The simulation results match with experimental data under several different cases, and therefore could be used as guideline to explain device performance without any destructive failure analysis. Parameters extracted from electrical derivatives could be used as screening to catch devices with inferior performance and potential reliability risk.

Record bit-rate-distance-products of 118.6 and 51.6 Gbpsxkm were achieved for PAM4 and NRZ transmission over a single OM4 fiber using mode-selective VCSEL. The OMA penalty was 3.1 dB for 51.56-Gbps-PAM4 transmission over 1.6km OM4 at BER of 5x10(-5).

In this paper, we present a simple circuit-level VCSEL model working over a broad range of ambient temperatures, while accounting for self-heating effects. We present the static, dynamic small signal and dynamic large signal performance compared to measurement results.

We use a system level simulation to study the transmission penalty for extended SR4 systems with 300 m OM3 MMF under two types of launch conditions and we show an impact of the fiber bandwidth on the equalized 25.78 Gbps VCSEL-based NRZ link at 850 nm.

We review several techniques for expanding the carrying capacity of multimode fiber (MMF) data links using short wavelength division multiplexing (SWDM) and selective modal launch. Our approach utilizing four SWDM vertical cavity surface emitting lasers (VCSELs) and novel diffractive optical components enables 100 GbE transmission in a single 300 m OM3 MMF lane.

This paper reviews and examines several techniques for expanding the carrying capacity of multimode fiber (MMF) using vertical cavity surface emitting lasers (VCSELs). The first approach utilizes short wavelength division multiplexing in combination with MMF optimized for operation between 850 and 950 nm. Both nonreturn to zero (NRZ) and four-level pulse amplitude modulation (PAM4) signaling are measured and demonstrate up to 170-Gb/s postforward error correction transmission over 300 m. For single wavelength transmission, the use of selective modal launch to increase the optical bandwidth of a standard OM3 MMF to more than 2.1 GHzkm for standard MMF is presented. A statistical model is used to predict the bandwidth enhancement of installed MMF and indicates that significant link extension can be achieved using selective modal launch techniques. These results demonstrate the continued effectiveness of VCSEL-based MMF links in current and future data center environments.

We present successful transmission of 52Gb/s PAM4 through -58 and +10 ps/nm of SMF using a single chip and directly modulated laser. The receiver sensitivities are compared using APD and PIN PD at the receiver.

Successful 180 (4×45) Gbps transmission is demonstrated over OM4 fibres using a 45-Gbps-PAM4 chip. Real time BERs<2e-4 were achieved for four SWDM grid channels in the 850–950nm wavelength range over 100m/200m/300m of wideband OM4 fibres.

We demonstrate successful transmission of four 45 Gbps PAM4 single-channels through OM4 multimode fibers (MMFs) and wideband MMF using a PAM4 PHY chip and four vertical cavity surface emitting lasers (VCSELs) with wavelengths ranging over short wavelength division multiplexing (SWDM) grid. Real-time bit error ratios (BERs) < 2 × 10-4 were achieved for all four 45 Gbps PAM4 SWDM grid channels over 100 m, 200 m, and 300 m of wideband OM4 MMFs. All four channel received PAM4 optical eyes are shown after propagating through 100 m, 200 m, and 300 m of wideband OM4 as well as 100 m and 200 m conventional OM4 MMFs. The measured BERs as a function of the inner eye optical modulation amplitudes (OMAs) are shown for all four SWDM grid channels. Inner eye OMAs ranged from -16.2 dBm to -13.5 dBm for different channels over different OM4 MMF types at the KP4 BER threshold of 2 × 10-4.

Experimental data is presented demonstrating 100GbE (4×25.8 Gbps) SWDM4 VCSEL technology, and SWDM4 transmission over 200m and 300m of wideband OM4 fibers. All NRZ SWDM4 channels achieved error-free transmission at 200m, and BER <; 1e-9 at 300m. In addition, successful 180 (4×45) Gbps transmission is demonstrated over 300m wideband OM4 fibers using a 45-Gbps-PAM4 chip. Real time BERs <; 2e-4 were achieved for all four SWDM grid channels in the 850-950nm wavelength range. Precise modal excitation in MMF fibers for improving the fiber bandwidth by minimizing modal dispersion is also discussed. Using our novel modal excitation method, 25 Gbps NRZ transmission over 300m OM3 is shown.

Real-time 52 Gbps PAM4 transmission is demonstrated over single mode fiber (SMF) using a directly modulated laser (DML) and a PHY chip. The inner eye optical modulation amplitude (OMA) receiver sensitivities were measured and compared using avalanche photodetector (APD) and PIN photodetector (PD) for the maximum and minimum chromatic dispersions (CDs) of 400GBase-LR8 link. The measured inner eye OMAs were -17.8 dBm and -18.8 dBm for + 10 ps/nm and -58 ps/nm of CDs at the KP4 bit error rate (BER) threshold of 2 × 10-4 using a PIN PD, respectively. The measured inner eye OMA was improved to -21.0 dBm for -58 ps/nm of CD at the KP4 BER threshold using an APD. Negligible OMA penalty (< 0.4 dB) was captured for operating DML at different bias currents of 40 mA and 60 mA using a PIN PD and an APD for both positive and negative CDs at the KP4 BER threshold.

The receiver sensitivity of 52 Gbps-PAM4 is investigated over OM3/OM4 fibers in real time. The measured sensitivities are compared and correlated with measured fiber bandwidths for 850/880 nm channels to examine 104 Gbps SWDM2-PAM4 transmission.

Experimental data is presented demonstrating 100GbE (4 × 25.8 Gb/s) SWDM4 VCSEL technology, and SWDM4 transmission over 200m and 300m of wideband OM4 fiber. All SWDM4 channels achieve error free transmission at 200m, and BER <; 1.e-9 at 300m.

This paper explores the feasibility of single-channel 50G and 100G transmission using 25G VCSEL technology. We show through experiments the practicality of 50G transmission through 100 m of OM3 multi-mode fiber. To address the question of whether single-channel 100G transmission is feasible, we show through simulation the needed reduction in relative intensity noise of 25G VCSELs and present a novel modulation technique which offers improved performance over conventional discrete multitone with little additional computational complexity.

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text L. F. Suhr, I. Lyubomirsky, H. M. Daghighian, C. Kocot, I. T. Monroy, and J. J. V. Olmos, "Comparing 52 Gbps Duobinary and 4-PAM Transmission Over 100m OM-3 Fiber With 25 GHz Class VCSELs," in Asia Communications and Photonics Conference 2015, C. Lu, J. Luo, Y. Ji, K. Kitayama, H. Tam, K. Xu, P. Ghiggino, and N. Wada, eds., OSA Technical Digest (online) (Optica Publishing Group, 2015), paper ASu4C.2. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Successful 180 (4x45) Gbps transmission is demonstrated over OM4 fibres using a 45Gbps-PAM4 chip. Real time BERs<2e-4 were achieved for four SWDM grid channels in the 850950nm wavelength range over 100m/200m/300m of wideband OM4 fibres. OCIS codes: (060.0060) Fiber optics communications; (060.4080) Modulation

We present experimental data demonstrating 45Gb/s VCSEL transmission over 200m of OM3 and 300m of wideband OM4 fibers at 850/940nm. The measured PAM4 OMA-sensitivity was -15.0 dBm at 2e-4 over 100m OM3 fiber at 850/940nm.

The vast majority of optical links within the data center are based on vertical cavity surface emitting lasers (VCSELs) operating at 850 nm over multimode optical fiber. Deployable links have evolved in speed from 1 Gb/s in 1996 to 28 Gb/s in 2014. Serial data links at 40 and 56 Gb/s are now under development and place even more demand on the VCSEL and photodiodes. In this paper, we present the characteristics of VCSELs and photodiodes used in current generation 28 Gb/s links and present several methods to extend link distances using more advanced data encoding schemes. Finally, we will present results on wavelength division multiplexing on multimode optical fiber that demonstrate 40 Gb/s Ethernet connections up to 300 m on duplex OM3 optical fiber, and present results on fiber optimized for modal bandwidth in the 850 to 980 nm range.