J.P. Turkiewicz

160 Gb/s OTDM networking using deployed fiber

This paper reports a 160-Gb/s OTDM network comprising switching and demultiplexing through field deployed fiber. The 160-Gb/s signal was obtained by time-interleaving 16 channels of a 10-Gb/s signal. The add-drop node was realized by using a gain-transparent operation of a semiconductor optical amplifier (SOA). A subharmonic clock recovery with a prescaled electrooptical phase locked loop employing an electroabsorption modulator was applied. An OTDM receiver employed a four-wave mixing principle in an SOA. The impact of fiber chromatic and polarization-mode dispersion (PMD) is discussed. Switching and demultiplexing performance are shown for a fiber link of 275 and 550 km, respectively. Excellent operation of clock recovery, drop-through-add function, and transmission was achieved.

Clock recovery by a fiber ring laser employing a linear optical amplifier

We report on subharmonic optical clock recovery (OCR) at 10 GHz from 160-Gb/s optical time-division multiplexed signals. The OCR circuit is based on a passively mode-locked principle in a fiber ring laser that utilizes fast gain dynamics of a linear semiconductor optical amplifier. To decrease the jitter amount in the clock pulse considerably, postelectrical signal processing is performed. The recovered clock is a 1.8-ps 10-GHz pulse train with 0.37 pulsewidth-bandwidth product.

Clock recovery and demultiplexing performance of 160-gb/s OTDM field experiments

Clock recovery (CR) from a 160-Gb/s data signal is demonstrated using a single unidirectional electroabsorption modulator in a cost-effective phase-locked loop configuration consisting entirely of commercially available components. The CR exhibits a root mean square time jitter of 205 fs, a holding range of 10 MHz, a wavelength-independent performance of 10 nm, and an input dynamic range of 10 dB. Demultiplexing experiments of transmitted 160-Gb/s data through installed fiber links over 275.4 km verified the excellent performance of the proposed CR. All 16 10-Gb/s channels were demultiplexed error-free.

Low Complexity up to 400-Gb/s Transmission in the 1310-nm Wavelength Domain

In this letter, we demonstrate low complexity dense wavelength-division multiplexing (DWDM) over a ~ 40-km standard single-mode fiber transmission system in the 1310-nm wavelength domain with a total transmission capacity up to 400 Gb/s. The demonstrated system is based exclusively on semiconductor components without any form of dispersion compensation. The system showed excellent performance. The presented results prove that the 1310-nm wavelength domain can support low cost and low complexity high-speed transmission with the wide range applications like the future 400G+ Ethernet.

Self-controlled all-optical label and payload separator for variable length bursts in a time-serial IM/DPSK scheme

We demonstrate an all-optical label and payload separator based on nonlinear polarization rotation in a semiconductor optical amplifier. The proposed scheme uses a variable packet length composed of a label and payload information signal modulated intensity modulation and differential phase-shift keying (DPSK) format, respectively. The separation is obtained by using the payload signal itself, exploiting the DPSK feature of being power constant, as a pumping light source. Therefore, the proposed scheme is asynchronous and does not need an external control signal.

Effective 100 Gb/s IM/DD 850-nm Multi- and Single-Mode VCSEL Transmission Through OM4 MMF

To cope with the ever increasing data traffic demands in modern data centers, new approaches and technologies must be explored. Short range optical data links play a key role in this scenario, enabling very high speed data rate links. Recently, great research efforts are being made to improve the performance of vertical-cavity surface-emitting lasers (VCSELs) based transmission links, which constitute a cost-effective solution desirable for massive deployments. In this paper, we experimentally demonstrate intensity-modulation direct-detection transmissions with a data rate of 107.5 Gb/s over 10 m of OM4 multimode fiber (MMF) using a multimode VCSEL at 850 nm, and up to 100 m of OM4 MMF using a single-mode VCSEL at 850 nm. Measured bit error rates were below 7% overhead forward error correction limit of 3.8e−03, thus, achieving an effective bit rate of 100.5 Gb/s. These successful transmissions were achieved by means of the multiband approach of carrierless amplitude phase modulation.

Single-Mode 850-nm VCSELs for 54-Gb/s ON–OFF Keying Transmission Over 1-km Multi-Mode Fiber

By combing Zn-diffusion and oxide-relief apertures with strong detuning (>20 nm) in our demonstrated short-cavity (λ/2) 850-nm vertical-cavity surface-emitting lasers (VCSELs), wide electrical-to-optical bandwidth (29-24 GHz), low-differential resistance (~100 Q), and (quasi) single-mode (SM) with reasonable output power (~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 (1 × 10-5 versus 1 × 10-2) 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 ~3.5×10-3 versus ~1.4×10-4 under the same received optical power.

Accelerated aging of 28 Gb s−1 850 nm vertical-cavity surface-emitting laser with multiple thick oxide apertures

850 nm vertical-cavity surface-emitting lasers with multiple thick oxide apertures suitable for temperature-insensitive error free transmission at 28 Gb s−1 are subjected to accelerated aging at high current densities and chip temperatures. The devices withstand a 20% power change test at a high current density () at an ambient temperature of for 2500 h. At 90– at this current density no degradation was observed up to 5000 h. We performed the studies at further elevated current densities and temperatures and define the acceleration factor as . The extrapolated lifetime for 20% power drop is estimated as 20 thousand years at 300 K at current density of which is sufficient for 28 Gb s−1 error-free temperature-insensitive data transmission.

High Speed Optical Data Transmission With Compact 850 nm TO-Can Assemblies

Key components of the optical interconnects are the fully integrated optical transmitter and receiver subassemblies. The required features of such components include high bit rate and energy efficient operation in the wide range of operating conditions as well as small dimensions. In this paper, operation of the transmitter and receiver micromodules integrated with the driving electronics into the TO-can packages is demonstrated. The evaluated TOSA and ROSA 850 nm link had a convolved -3 dB bandwidth of ~ 21 GHz. Data transmission utilizing TOSA and ROSA pair up to 28 Gb/s is demonstrated in temperature range of 25°C/85°C with the nominal and up 43% reduced power consumption as well as the limited to 330 mVpp driving voltage. Results of the multiple TOSA and ROSA link measurements show limited performance spread. Finally, error-free operation up to 38 Gb/s is presented. The obtained results indicate a high potential of 850 nm VCSEL and PIN-based TO-can assemblies for the next generation of energy-efficient high bit rate optical interconnects.

Outdoor

This letter proposes a W-band hybrid photonic wireless link based on a commercial small form-factor pluggable (SFP+) module and experimentally demonstrates its performance. Using a free running laser as local oscillator and heterodyne photonic upconversion, good frequency stability is achieved. Outdoor wireless transmission over 225 m with a bit error rate below 10-6 is demonstrated, and the maximum reach of the system with typical RF components is calculated, finding wireless distances above 2 km to be feasible. Being based on a commercial SFP+, the proposed hybrid photonic wireless link offers seamless integration with existing distribution networks and passive optical networks, and thus paves the way for future mobile frontand backhaul architectures.