Fiscal Year 2023
Over the past decade, passive, nonlinear optical resonators have emerged as a new method for generating ultrashort optical pulses and the corresponding broadband frequency comb. This study explores a new method for generating ultrashort pulses using passive resonators. By taking advantage of silica's inherent nonlinear Raman amplification, low-noise dissipative solitons with durations well below 100 fs have been successfully and decisively generated via resonator phase-locked pulses generated by standard commercial optical fibers. The physics of the new dissipative Raman soliton state is explored to identify the scaling laws governing the pulse characteristics, allowing the output repetition rate to be freely scaled without affecting the soliton duration. The technique achieves the shortest pulses ever generated in commercially available optical fiber (active or passive) and has the potential to be transferred to chip-scale formats using existing dispersion-engineered silica microcavities.
Optical chaos is vital for various applications such as private communication, encryption, anti-interference sensing, and reinforcement learning. Chaotic microcombs have emerged as promising sources for generating massive optical chaos. In this study, we present massively parallel In this study, we present massively parallel chaos based on chaotic microcombs and high-nonlinearity AlGaAsOI platforms. We further show the application of our approach by demonstrating a 15-channel integrated random bit We further show the application of our approach by demonstrating a 15-channel integrated random bit generator with a 20 Gbps channel rate using silicon photonic chips. Our work opens new possibilities for chaos-based information processing Our work opens new possibilities for chaos-based information processing using integrated photonics, and potentially can revolutionize the current architecture of communication, sensing and computations.
This work proposes a novel dual-mode photonic-crystal waveguide that realizes direct in-plane resonant excitation of the embedded QDs. The device relies on a two-mode waveguide design, which allows exploiting one mode for excitation of the QD and the other mode for collecting the emitted single By proper engineering of the photonic band-structure, single-photon collection efficiency of β > 0.95 together with a The device has a compact footprint of ∼50 μm2 and would The device has a compact footprint of ∼50 μm2 and would enable stable and scalable excitation of multiple emitters for multi-photon quantum applications.
Soliton microcombs have shown great promise as a photonics-derived low-noise microwave generation technology. However, the repetition rate of a microcomb is basically determined by the size of the resonator, limiting the ability to tune the broadband and fast frequency by tuning the heat and pump frequency. In this study, we demonstrate a microwave soliton microcomb that can be tuned at high repetition rates by using a new device configuration. By incorporating electro-optic modulators along the ring waveguide, we succeeded in modulating a 75 MHz bandwidth at 5.0x10^14 Hz/s, which is several orders of magnitude faster than the modulation speed of conventional techniques. The device is expected to be applied to many applications including frequency measurement, frequency synthesizer, LiDAR, sensing, and communications.
Micro-optical resonators are promising platforms for highly efficient light-matter interactions. In recent years, the combination of nanoscale micro-optical resonators and 2D materials has further enriched optoelectronics in micro-optical resonator geometries, spurring a wide range of advances in lasers, nonlinear converters, modulators, and sensors. Here we report a compact dual laser resonance concept in graphene-microoptical resonator fibers. Driven by a single 980-nm pump, orthogonally polarized laser lines are generated with a pair of mode-breaking degeneracies; the two laser lines produce a heterodyne beat note at 118.96 MHz, with frequency noise down to 200 Hz^2/Hz at a 1-MHz offset, and in vacuum The line width was 930 Hz. This compact instrument allows on-line and label-free detection of ammonia gas with high resolution and a detection limit at the single pmol/L level.
In this paper we propose and numerically demonstrate a broadband, wavelength tunable Raman soliton source based on an As2Se3 waveguide. The input waveguide exhibits an anomalous dispersion in the near-infrared band, thereby enabling a 1.96 μm light source for Raman soliton self-frequency shift (SSFS) excitation. The output waveguide exhibits large anomalous dispersion and good mode confinement in the mid-IR band, thus supporting further SSFS processes. 2.29-4.57 μm wavelength tunable Raman light sources are theoretically realized on this on-chip platform. This study presents a simple and easy-to-implement strategy for extending the tuning range of the light source. The proposed tunable wavelength light source has great potential in integrated spectroscopy, gas detection, and LiDAR applications.
The high-frequency carrier, terahertz (THz) waves, have an ultra-wide bandwidth and are therefore suitable for high data ray
It is essential to achieve wireless transmission of the To enable multi-level modulation, phase
Stabilization is extremely important, and we have previously developed a phase stabilization technique using Mach-Zehnder interferometry.
generated. However, in this method, when generating phase-modulated THz waves, the phase modulator
had a problem of affecting the phase stabilization system. Therefore, we have developed a THz wave generation shi
A new phase stabilization approach was devised using light waves in the opposite direction of the stem. The result
As a result, error-free transmission was demonstrated at modulation frequencies above 3 Gbit/s.
An efficient 1.7-μm Tm-doped fiber laser with a resonator incorporated into a 1560-nm erbium/ytterbium resonant fiber laser cavity was demonstrated, and a rate equation model was developed to optimize fiber length and output coupling to achieve the desired output power. Experiments showed a maximum output power of 1.13 W at 1720 nm under a diode pump power of 10 W at 976 nm, which correlated well with the modeling. The slope efficiency from the multimode 976nm diode pump to 1720nm output was 13.5%, and the slope efficiency at the start-up 1560nm pump power reached 62.5%. A high signal-to-noise ratio of over 65 dB was achieved by using a short Tm-doped fiber to minimize signal reabsorption. Further power scaling prospects based on the developed model were also discussed.
Flat optics has demonstrated great advances in miniaturizing conventional bulky optical elements due to recent developments in metasurface design. Specific applications of such designs include spatial differentiation and the compression of free-space. In this work, we introduce a polarization-independent In this work, we introduce a polarization-independent metasurface structure by designing guided resonances with degenerate band curvatures in a photonic crystal slab. Our device can perform both free- space compression and spatial differentiation when operated at different frequencies at normal incidence. This work demonstrates the promise of dispersion engineering in metasurface design to create ultrathin devices with polarization-independent functionality.
We propose a new method to generate single solitons in SiN resonators. The auxiliary laser method pumps two resonances and compensates thermally with one of them, but this method is inefficient because the two resonances are separated by an FSR, which requires a pump and a separate laser. In the present study, by appropriately designing a two-mode resonator and using two resonances with very close resonance frequencies, a soliton was successfully generated with only one pump laser.
Optical chaos communication and key distribution have been extensively demonstrated with high-speed advantage but only within the metropolitan-area network range of which the transmission distance is restricted to around 300 km. For secure-transmission requirement of the backbone fiber link, the critical threshold is to realize long-reach chaos synchronization. Here, we propose and demonstrate a scheme of long-reach chaos synchronization Here, we propose and demonstrate a scheme of long-reach chaos synchronization using fiber relay transmission with hybrid amplification of an erbium-doped fiber amplifier (EDFA) and a distributed fiber Raman amplifier (DFRA). Experiments and simulations show that the hybrid amplification extends the chaos-fidelity transmission distance thanks to that the low-noise DFRA Optimizations of the hybrid-relay conditions are studied, including Optimizations of the hybrid-relay conditions are studied, including launching power, gain ratio of DFRA to EDFA, single-span fiber length, and number of fiber span. coefficient beyond 0.90 is experimentally achieved, which underlies the backbone network-oriented optical chaos communication and key distribution .
Integrated microwave photonic filters (IMPFs) have broadband and re
Polarization selective elements can control the polarization of an optical system.
with pseudo-crossing differences, and with certainty.2Observation of soliton formation
Dissipative Kerr solitons in micro resonators (DKS(see Figure 2), the
Multipoint side pump 2.825µm high density el.
To deploy spectrometers on mobile platforms, small spectrometers
Advances in integrated photonics have led to the development of highly stable, compact, broadband comb generators for a variety of applications, including communications, distance measurement, spectroscopy, frequency measurement, optical computation, and quantum information. Broadband optical frequency combs are generated in an electro-optic cavity where light passes through a phase modulator multiple times and circulates within an optical cavity. However, current broadband electro-optic frequency combs are limited by their low conversion efficiency. In this study, we demonstrate an integrated electro-optic frequency comb with a conversion efficiency of 301 TP3T and an optical span of 132 nm using a thin-film lithium niobate-based coupling resonator platform. Furthermore, by leveraging the high efficiency, the device can act as an on-chip femtosecond pulse source (pulse width of 336 fs), which is important for applications such as nonlinear optics, sensing, and computation.
Expected to be used in automated drivingLight Detection and Ranging (LiDAR)The conventional method for
Abstract: For the first time, to the best of our knowledge, we experimentally demonstrate a high-speed free-space secure optical communication system The effect of atmospheric turbulence on optical chaos synchronization is experimentally investigated via a hot air convection atmospheric turbulence simulator. It is shown that, even under moderately strong turbulent conditions, high-quality chaos Moreover, a secure encryption transmission experiment using a high bias Moreover, a secure encryption transmission experiment using a high bias current induced chaotic carrier for 8-Gbit/s on-off-keying data over a ∼10-m free-space optical link is successfully demonstrated, with a bit-error rate below the FEC threshold of 3 rate below the FEC threshold of 3.8 × 10-3. This work favorably shows the feasibility of optical chaotic encryption for the free-space optical transmission system.
are highly on demand in practice, but the majority of previously proposed
photonic systems have been limited to fixed performances, once fabricated.
Although several approaches have been proposed for obtaining the tunability
in topological photonic systems, they are limited to first-order topological
states and require rather complicated structures. Herein, second-order
topological properties of rhombic photonic crystals (PCs) are revealed, for
For the first time, enabling to realize tunable photonic devices.
purpose, the conventional square lattice PCs composed of four rigid
Dielectric rods are reshaped to rhomboid ones with preserved inversion
symmetry, which exhibit well-quantized bulk polarizations.
eigenfrequencies of topological edge and corner states depend on the angle
between the neighboring sides of unit cells, the second-order topological
systems exhibit dynamic tunability, being useful for diverse applications
Such as optical switching and flexible beam control.
results for reconfigurable routing limited to special angles, this
lattice-reshaping mechanism has the ability to realize dynamically tunable
routing, extending the realm of applications of topological photonics.
its simplicity and feasibility, this mechanical lattice-reshaping approach
paves the way toward higher-order topological photonic devices with
dynamically controlled functions.
Highly sensitive detection of molecules without the use of labels or trapping agents
Soliton microcomputers have been widely studied for their versatility
The laser is compact and has a structure near 3 µm.
We propose nanostructures (photonic crystals) whose optical properties change spontaneously only by the application of static voltage to accelerate photonics technology. We have applied the proposed photonic crystals to PCSELs and demonstrated that pulsed oscillation occurs without any external switching operation. This achievement is significant as a new method of PCSEL pulse generation and will lead to a deeper understanding of the phenomena caused by carrier photon dynamics.
We have developed a Nd-doped cascade Raman laser for the development of two-photon microscopy for deep biological imaging. In order to suppress the mode competition between 1060nm and 900nm, we developed a mode-locked cascade Raman laser that can be easily fabricated by using bending loss.
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This is an open lecture series held in Tanabe Photonic Structures Laboratory. Students who are graduate students or above will survey papers related to optics and related technologies such as photonics, materials, bioscience, etc., and explain them in an easy-to-understand manner.
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