ORCID Profile
0000-0002-8859-0986
Current Organisation
Technical University of Denmark
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Publisher: Optica Publishing Group
Date: 25-08-2020
DOI: 10.1364/OL.400230
Abstract: Silicon photonic integrated circuits (PICs) show great potential for many applications. The phase tuning technique is indispensable and of great importance in silicon PICs. An optical phase shifter with balanced overall performance on power consumption, insertion loss, footprint, and modulation bandwidth is essential for harnessing large-scale integrated photonics. However, few proposed phase shifter schemes on various platforms have achieved a well-balanced performance. In this Letter, we experimentally demonstrate a thermo-optic phase shifter based on a densely distributed silicon spiral waveguide on a silicon-on-insulator platform. The phase shifter shows a well-balanced performance in all aspects. The electrical power consumption is as low as 3 mW to achieve a π phase shift, the optical insertion loss is 0.9 dB per phase shifter, the footprint is 67 × 28 µ m 2 under a standard silicon photonics fabrication process without silicon air trench or undercut process, and the modulation bandwidth is measured to be 39 kHz.
Publisher: IEEE
Date: 09-2018
Publisher: Optica Publishing Group
Date: 2022
DOI: 10.1364/CLEO_AT.2022.JTH6B.8
Abstract: We demonstrate a high-performance graphene-silicon slot-waveguide electro-optic micro-ring modulator featuring a record modulation efficiency of 10.99 V -1 µm -1 with a 33-dB extinction ratio, 8-µm-long graphene and a modulation bandwidth of GHz.
Publisher: IEEE
Date: 09-2014
Publisher: Optica Publishing Group
Date: 07-2020
DOI: 10.1364/OE.397130
Abstract: We have proposed and demonstrated the optical time-and-polarization interleaving (OTPI) technique, which can effectively extend the transmitter bandwidth for an intensity modulation and direct detection (IM/DD) optical system. The 224-Gbit/s line-rate OTPI-PAM-4 signal is successfully transmitted over a 500-m standard single-mode fiber (SSMF) in the C band, using the transmitter with a bandwidth of 25 GHz and the receiver with a single photodiode. By using a 33%-return-to-zero (RZ) pulse train, a bit-error ratio (BER) below 7% hard-decision forward error correction (HD-FEC) threshold is achieved. BER below 20% soft-decision forward error correction (SD-FEC) threshold is also realized using a carrier suppressed return-to-zero (CSRZ) pulse train. The OTPI technique can also be used for more higher-order pulse litude modulation (PAM) formats, making it a promising technique for next-generation high-speed optical interconnects.
Publisher: Springer Science and Business Media LLC
Date: 20-10-2022
Publisher: Institution of Engineering and Technology
Date: 2019
DOI: 10.1049/CP.2019.1096
Publisher: Springer Science and Business Media LLC
Date: 16-03-2022
DOI: 10.1038/S41467-022-29049-2
Abstract: Photonic generation of Terahertz (THz) carriers displays high potential for THz communications with a large tunable range and high modulation bandwidth. While many photonics-based THz generations have recently been demonstrated with discrete bulky components, their practical applications are significantly hindered by the large footprint and high energy consumption. Herein, we present an injection-locked heterodyne source based on generic foundry-fabricated photonic integrated circuits (PIC) attached to a uni-traveling carrier photodiode generating high-purity THz carriers. The generated THz carrier is tunable within the range of 0–1.4 THz, determined by the wavelength spacing between the two monolithically integrated distributed feedback (DFB) lasers. This scheme generates and transmits a 131 Gbits −1 net rate signal over a 10.7-m distance with −24 dBm emitted power at 0.4 THz. This monolithic dual-DFB PIC-based THz generation approach is a significant step towards fully integrated, cost-effective, and energy-efficient THz transmitters.
Publisher: Research Square Platform LLC
Date: 20-01-2022
DOI: 10.21203/RS.3.RS-1086400/V1
Abstract: Despite being perceived historically to provide "unlimited" bandwidth, today’s optical communication systems are fast approaching their capacity limits in the conventional telecom bands. To satisfy the ever-increasing capacity demand, opening up new wavelength bands is becoming an appealing solution both in cabled and free-space optical communications in the transparent windows. However, this would ordinarily require the development of whole optical transceivers for any new wavelength band, which is both time-consuming and expensive. Here, we present an on-chip continuous spectral translation based coherent optical communication approach that can exploit existing commercial transceivers to unlock the vast and currently unused potential new wavelength bands rather than dictate the need to develop new coherent transceivers operating directly in those bands. The spectral translators are continuous-wave pumped aluminium gallium arsenide on insulator (AlGaAsOI) nanowaveguides that can provide a continuous conversion bandwidth over an octave. This enables unprecedented coherent transmission in the 2-μm wavelength band using well-developed conventional C-band transmitters and coherent receivers. We demonstrate 318.25-Gbit s -1 Nyquist wavelength- ision multiplexed coherent transmission over a 1.15-km hollow-core fibre in the 2-μm wavelength band using this approach. Our demonstration paves the way for coherently transmitting, detecting, and processing signals at wavelength bands beyond the capability of today’s devices.
Publisher: IEEE
Date: 12-2020
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/IPRSN.2020.ITU2A.1
Abstract: We discuss and review the Kerr-effect-based broadband optical signal processing in high-index-contrast AlGaAs-on-insulator waveguides, which is enabled by a combination of an ultra-high nonlinearity and efficient dispersion engineering.
Publisher: Institution of Engineering and Technology
Date: 2019
DOI: 10.1049/CP.2019.0999
Publisher: IEEE
Date: 05-11-2022
Publisher: OSA
Date: 2016
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2021
Publisher: Institution of Engineering and Technology
Date: 2019
DOI: 10.1049/CP.2019.0833
Publisher: Springer Science and Business Media LLC
Date: 16-07-2022
DOI: 10.1038/S41467-022-31884-2
Abstract: Today’s optical communication systems are fast approaching their capacity limits in the conventional telecom bands. Opening up new wavelength bands is becoming an appealing solution to the capacity crunch. However, this ordinarily requires the development of optical transceivers for any new wavelength band, which is time-consuming and expensive. Here, we present an on-chip continuous spectral translation method that leverages existing commercial transceivers to unlock the vast and currently unused potential new wavelength bands. The spectral translators are continuous-wave laser pumped aluminum gallium arsenide on insulator (AlGaAsOI) nanowaveguides that provide a continuous conversion bandwidth over an octave. We demonstrate coherent transmission in the 2-μm band using well-developed conventional C-band transmitters and coherent receivers, as an ex le of the potential of the spectral translators that could also unlock communications at other wavelength bands. We demonstrate 318.25-Gbit s −1 Nyquist wavelength- ision multiplexed coherent transmission over a 1.15-km hollow-core fibre using this approach. Our demonstration paves the way for transmitting, detecting, and processing signals at wavelength bands beyond the capability of today’s devices.
Publisher: IEEE
Date: 05-11-2022
Publisher: Optica Publishing Group
Date: 25-02-2020
DOI: 10.1364/OE.384805
Abstract: Two-dimensional eight-level pulse litude modulation with trellis-coded modulation (2D-TCM-PAM8) is proposed to overcome the bandwidth limitation for high-speed signal transmission due to its high spectral efficiency. However, the high coding gain of the TCM can only be achieved in bandlimited additive white Gaussian noise (AWGN) channels and cannot be achieved in nonlinear channels without any equalizers. In the directly modulated laser and direct detection (DML-DD) transmission system, the transceiver nonlinearities and the interaction between DML chirp and fiber dispersion will introduce nonlinear distortion. To compensate for the nonlinear distortion, we propose a computationally efficient piecewise linear (PWL)-Volterra equalizer. In this equalizer, we first use the PWL to correct the skewed eye diagram and then employ a simple 2 nd order Volterra to compensate for the residual nonlinear distortions. By using the PWL-Volterra equalizer prior to the Viterbi decoder, the high coding gain of TCM can be achieved. In the experiment, a 104 Gb/s 8-state 2D-TCM-PAM8 signal generated in a ∼ 20 GHz DML is successfully transmitted over 10 km standard single-mode fiber (SSMF) in C band, with the bit error ratio (BER) below the HD-FEC limit of 3.8 × 10 −3 . Compared to only using the conventional 2 nd order Volterra equalizer with a similar BER performance, the PWL-Volterra equalizer shows 29% computational complexity reduction.
Publisher: AIP Publishing
Date: 10-2019
DOI: 10.1063/1.5115232
Abstract: Wavelength conversion technology is imperative for the future high-speed all-optical network. Nonlinear four-wave mixing (FWM) has been used to demonstrate such functionality in various integrated platforms because of their potential for the realization of a chip-scale, fully integrated wavelength converter. Until now, waveguide-based wavelength conversion on a chip requires a pump power beyond the reach of available on-chip lasers. Although high-quality factor (Q) microresonators can be utilized to enhance the FWM efficiency, their narrow resonance linewidths severely limit the maximal data rate in wavelength conversion. In this work, combining the ultrahigh effective nonlinearity from a high-confinement aluminum gallium arsenide waveguide and field enhancement from a microring resonator with a broad resonance linewidth, we realize all-optical wavelength conversion of a 10-Gbaud data signal by using a pump power, for the first time, at a submilliwatt level. With such a low operation power requirement, a fully integrated high-speed wavelength converter is envisioned for the future all-optical network. The waveguide cross-sectional dimension is engineered in a submicron scale to enhance the light confinement, which pushes the device effective nonlinearity to 720 W−1 m−1 while maintaining a broad operation bandwidth covering the telecom S-, C-, and L-bands. Moreover, we demonstrate that a single microring resonator is capable of handling a high-speed data signal at a baud rate up to 40 Gbit/s. All the wavelength conversion experiments are validated with bit-error rate measurements.
Publisher: OSA
Date: 2010
Publisher: The Optical Society
Date: 23-12-2013
DOI: 10.1364/OE.22.000110
Publisher: Optica Publishing Group
Date: 2021
DOI: 10.1364/CLEO_SI.2021.SF1C.1
Abstract: We propose and demonstrate the first low-latency 2-μm-band coherent N-WDM transmission by on-chip spectral translation of 4×32-Gbaud 16-QAM signals with 33-GHz spacing. 318.25 Gbit/s net-rate is achieved with error-free performance after 1.15-km hollow-core fiber transmission.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 02-2020
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2021
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-04-2020
Publisher: Optica Publishing Group
Date: 29-07-2010
DOI: 10.1364/OE.18.017252
Publisher: Optica Publishing Group
Date: 10-02-2020
DOI: 10.1364/OL.383085
Abstract: Exploring new frequency bands for optical transmission is essential to overcome the capacity crunch. The 2-µm band is becoming a research spotlight due to available broadband thulium-doped fiber lifiers as well as low-latency, low-loss hollow-core fibers. Yet most of the 2-µm band devices designed for optical communication are still in their infancy. In this Letter, we propose wavelength conversion based on four-wave mixing in a highly nonlinear AlGaAsOI nanowaveguide to bridge the 2-µm band and the conventional bands. Due to the strong light confinement of the AlGaAsOI nanowaveguide, high-order phase match is enabled by dispersion engineering to achieve a large synergetic conversion bandwidth with high conversion efficiency. Simulation results show a possible conversion bandwidth over an octave. An AlGaAsOI nanowaveguide with 3-mm length and a nominal cross-section dimension of 320 n m × 680 n m is used for the wavelength conversion of a 10 Gbit/s non-return-to-zero on–off keying signal and a 10 Gbit/s Nyquist-shaped four-level pulse- litude modulation signal. A conversion efficiency of − 28 d B is achieved using a 17.5-dBm continuous-wave pump in the C band, with 744 nm conversion from 1999.65 to 1255.35 nm.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2020
Publisher: Institution of Engineering and Technology
Date: 2013
DOI: 10.1049/CP.2013.1394
Publisher: IEEE
Date: 07-2019
Publisher: The Optical Society
Date: 24-06-2019
DOI: 10.1364/OE.27.019156
Location: Germany
No related grants have been discovered for Hao Hu.