Nonlinearity-Free Coherent Transmission in Hollow-Core Antiresonant Fiber

Self Cite

We report a Nested Antiresonant Nodeless hollowcore Fiber (NANF) operating in the first antiresonant passband. The fiber has an ultrawide operational bandwidth of 700 nm, spanning the 1240-1940 nm wavelength range that includes the O-, S-, C-and L-telecoms bands. It has a minimum loss of 6.6 dB/km at 1550 nm, a loss ≤ 7 dB/km between 1465-1655 nm and ≤ 10 dB/km between 1297-1860 nm. By splicing together two structurally matched fibers and by adding single mode fiber (SMF) pigtails at both ends we have produced a ~1 km long span. The concatenated and connectorized fiber has an insertion loss of approximately 10 dB all the way from 1300 nm to 1550 nm, and an effectively single mode behavior across the whole spectral range. To test its data transmission performance, we demonstrate 50-Gb/s OOK data transmission across the O-to L-bands without the need for optical amplification, with bit-error-rates (BERs) lower than the 7% forward error correction (FEC) limit. With the help of optical amplification, 100-Gb/s PAM4 transmission with BER lower than the KP4 FEC limit was also achieved in the O/E and C/L bands, with relatively uniform performance for all wavelengths. Our results confirm the excellent modal purity of the fabricated fiber across a broad spectral range, and highlight its potential for wideband, low nonlinearity, low latency data transmission. Index Terms-Fiber optics communications, hollow core optical fibers, microstructured optical fibers.

Section: Transmission Resultsmentioning

confidence: 99%

Section: B Setup Of the Transmission Experimentsmentioning

confidence: 99%

Interband Short Reach Data Transmission in Ultrawide Bandwidth Hollow Core Fiber

Sakr

Bottrill

Taengnoi

et al. 2020

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“…In [19], up to 73.7-Tb/s transmission over a 310-m length of photonic bandgap HCF was reported. A recent demonstration showed multi-terabit/s nonlinearity-free coherent transmission over a 270-m-long antiresonant HCF and numerically validated the advantages of HCF in long-haul applications [20]. Although relatively long-distance (up to 340 km) HCF-based transmission experiments have been conducted using a re-circulating loop in [22,23], current challenges in both fibre loss and the fabrication of uniform fibre structure over long lengths currently constrain realistic HCF transmission trials to relatively short distances.…”

Section: Introductionmentioning

confidence: 82%

“…To date, most high-speed HCF-based data transmission experiments were demonstrated using coherent detection [19][20][21][22][23], which is however mainly used in long-haul applications. In [19], up to 73.7-Tb/s transmission over a 310-m length of photonic bandgap HCF was reported.…”

Section: Introductionmentioning

confidence: 99%

Multi-Band Direct-Detection Transmission Over an Ultrawide Bandwidth Hollow-Core NANF

Hong

Sakr

Taengnoi

et al. 2020

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In this paper, we report high-speed multi-band direct-detection (DD) transmission over a hollow-core nested antiresonant nodeless fiber (NANF). Thanks to the ultrawide bandwidth of the NANF, we demonstrate dual-band transmission across the O-and C-bands over a ~1-km length of a hollow-core fiber for the first time. Eight wavelength-division multiplexed (WDM) channels were transmitted using 100-Gb/s/ Nyquist 4-ary pulse-amplitude modulation (PAM4) signals, which to the best of our knowledge, is the highest aggregate capacity ever transmitted in a DD hollow-core fiber-based transmission system. Optical pre-amplification was adopted for signal reception in both bands, achieved using an in-house built bismuth-doped optical fibre amplifier (BDFA) and a commercial erbium-doped fiber amplifier (EDFA) in the O-and C-band, respectively. We further demonstrate beyond 100-Gb/s/λ adaptively-loaded discrete multitone (DMT) transmission over the S+C+L-bands using the same NANF, without the use of optical amplification. Our experiments show that apart from fiber loss, the use of the NANF did not introduce any additional transmission penalties. The demonstrated results validate the ultrawide bandwidth and excellent modal purity of the fabricated NANF, which allow beyond 100-Gb/s/ penalty-free transmission over multiple bands, highlighting the potential of this fiber technology for high-speed short-to intermediate-reach applications.

“…In addition to the benefits from low TCD, the HCF has the advantages of ultra-wide transmission window (e.g., >100 nm [12]), promising potential coarse wavelength division multiplexing (CWDM) for low-cost 800 Gb/s and above data interconnection. The additional features like low nonlinearity and low chromatic dispersion across a broad wavelength range potentially promises high power budget for low-cost interconnections without consumed power and latency degradation necessary for the impairment compensation [18].…”

Section: Discussionmentioning

confidence: 99%

Low Thermal Sensitivity Hollow Core Fiber for Optically-Switched Data Centers

Clark

Chen

Fokua

et al. 2020

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Optical switches offer several benefits over electronics switches, including better scalability, lower power consumption, and lower latency. However, their implementation faces several challenges, including electronic transceivers to be able to support sub-nanosecond clock and data recovery time. This is required to efficiently handle data center traffic that is dominated by small data packets. Recent research shows that, scalable and sub-nanosecond data recovery can be achieved by synchronizing the clocks of all end-points connected to an optical switch in frequency and phase. In such a system, thermallyinduced change of propagation time through standard single mode fiber (SMF-28) necessitates the clock phases to be tracked due to variations in the data centers temperature. Hollow core fiber has been shown to have a thermal coefficient of delay 20 times smaller than SMF-28, offering potential to simplify the clock phase tracking and to increase the distance scale of data center networks. In this paper, we show how the low thermal coefficient of delay in hollow core fiber enables sub-nanosecond optical switching system with only initial frequency and phase synchronization. We obtained error-free real-time transmission of 60 ns packets over 1 km clock and 1 km hollow core data fiber with under 625 ps clock recovery time in both a point-to-point and a 2-to-1 optically switched 25.6 Gb/s real-time system. Based on our results, we estimate that sub-nanosecond clock recovery can be achieved for a 100 m size data center cluster interconnected by an optical switch using hollow core fiber, frequency synchronization and only a single phase calibration at the start-up.