Gong-Ru Lin

National Taiwan University | NTU · Graduate Institute of Photonics and Optoelectronics

For weak coherent single-photon secure data communication among short-reach metropolitan intra-/inter-city networks at the O-band (1250-1350 nm), the commercially available semiconductor laser sources are emerging but still suffering from high single-mode-fiber (SMF) loss, broad linewidth, and unstable wavelength. To overcome such disadvantages for...

In comparison with the rapidly developing progress on the optical C-band (1525-1565 nm) master-to-slave injection-locked transmitter to perform the coherent single-photon quantum key distribution (QKD), the development on the O-band (1250-1350 nm) QKD transmitter is somewhat delayed as the commercially available wavelength-matched narrow-linewidth...

This study showcases a method for achieving high-performance yellow and red micro-LEDs through precise control of indium content within quantum wells. By employing a hybrid quantum well structure with our six core technologies, we can accomplish outstanding external quantum efficiency (EQE) and robust stripe bandwidth. The resulting 30 μm × 8 micro...

The photonic-crystal-structured surface-emitting laser with a low-divergent-beam angle of 4.5 mrad can perform either 5.5-Gbit/s NRZ-OOK, or 16-Gbit/s broadband QAM DMT or 19.2-Gbit/s bit-loaded DMT formats for 30-cm short-reach point-to-point free-space-optical communication link.

White-lighting lamp beam with an all-in-one TO-can-packaged RGB-LD chip is performed with an illuminance of >300 lux, a CRI of >80, and a CCT of 6500K for free-space-optical wireless 16-QAM DMT link at 38.4 Gbit/s.

Master-to-slave injection-locked dual-mode diode laser is proposed for providing the single-photon DPS-QKD transmission at a shifted key rate of 1 Gbit/s with >3000-sec decoding stability under an interferometric visibility of 99.2% and dual-wavelength usage security.

A novel single-photon differential phase-shift keying (DPSK) scheme with asymmetric high-bit-rate coding (at 192 Mbit/s) and low-bit-rate gating (1 Mbit/s) coding data format is proposed to stabilize the long-term and long-distant point-to-point secure communication over 40-km standard single-mode-fiber (SSMF). The single-photon carrier is served b...

The direct modulation and fiber transmission performances of a bi-layer-oxide-confined 850-nm vertical cavity surface emitting laser (VCSEL) containing an emission aperture size of 3.5 μm with versatile novel complex data formats are compared. With delivering quadrature amplitude modulation-orthogonal frequency-division multiplexing (QAM-OFDM), gen...

A silicon (Si) Mach-Zehnder modulator (MZM) is demonstrated for 10-km SMF Link at C-band (1550 nm), which allows the pre-emphasized 4-level pulse amplitude modulation (PAM-4) data transmission at 50 GBaud (100 Gbit/s) per channel. By employing the pre-emphasis to the PAM-4 data over different links, the channel dispersion-induced power fading can b...

Amorphous-Ge (α-Ge) or free-standing nanoparticles (NPs) synthesized via hydrogen-free plasma-enhanced chemical vapor deposition (PECVD) were applied as transmissive or reflective saturable absorbers, respectively, for starting up passively mode-locked erbium-doped fiber lasers (EDFLs). Under a threshold pumping power of 41 mW for mode-locking the...

By employing a dual-wavelength (2-λ) vertical cavity surface emitting laser (VCSEL) directly encoded by novel quadrature amplitude modulation generalized frequency division multiplexing (QAM-GFDM) modulation schemes with optimized data capacity, a 28-GHz millimeter-wave-over-fiber (MMWoF) link is created for fusing the long-reach single-mode-fiber...

Bit-loaded quadrature amplitude modulation-orthogonal frequency division multiplexing (QAM-OFDM) encoding and photonic-crystal-engineered multi-mode vertical-cavity surface-emitting lasers (MM-VCSELs) transmission performance are analyzed. Two different surface photonic-crystal designs are used to configure the core and cladding regions of MM-VCSEL...

Though light-emitting diodes (LEDs) combined with various color conversion techniques have been widely explored for VLC (visible light communication), E-O (electro-optical) frequency responses of devices with quantum dots (QDs) embedded within the nanoholes have rarely been addressed. Here we propose LEDs with embedded photonic crystal (PhC) nanoho...

Red-green-blue (RGB) full-color micro light-emitting diodes (µ-LEDs) fabricated from semipolar (20-21) wafers, with a quantum-dot photoresist color-conversion layer, were demonstrated. We also demonstrated high-stability quantum dot-converted 3-in-1 full-color mini-light-emitting diodes passivated with low-temperature atomic layer deposition. A hyb...

By master-to-slave injection-locking and wavelength-to-phase-shift-keying an O-band TO-can-packed DFBLD at 1308.396 nm, the delayed-interferometric on-off-keying with Δθ=180° is achieved via direct master modulation at ΔI pp =0.1mA/Δλ=0.4pm or ΔV pp =60.6 mV/Δλ=0 under overlapped or deviated master/slave coding, respectively.

A below-threshold biased laser diode under modulated injection-locking with binary and triangular sequenced DPSK-QKD protocols with allowable phase-stabilized decoding up to 100Gbits in 12-min is successfully synthesized by using its leading-edge chirped pulse carrier.

Wavelength selective injection-locking of a 1545.59-/1548.18-nm dual-mode DFBLD with a transient-current-switched single-mode master DFBLD is performed for differential phase-shift-keying and delay-interferometric on-off-keying at 192 MHz that enables secure and complex quantum-key-distribution via alternative wavelength switching.

Constructing polaritonic devices in monolithic, ultra‐compact photonic architectures with monolayer‐featured exciton‐emitters is decisive to exploit the coherent superposition between entangled photonic and excitonic eigenstates for potential realizations of optical nonlinearities, macroscopic condensations, and superfluidity. Here, a feasible stra...

Group-IV semiconductor compounds with intense optical nonlinearity have emerged as a new branch of all-optical processing materials benefiting from the manufacturing compatibility with silicon electronic and photonic integrated circuits. Owing to the chemical reforming on the bonding or precipitating feature of the compositional atoms in the membra...

By the pulsed, heterodyned, and modulated laser illuminations, the impulse and noise responses of O-band germanium (Ge) p-i-n waveguide photodetector (WPD) with different transmission-line designs are characterized for receiving the NRZ-OOK data beyond 60 Gbit/s. The Ge lateral p-i-n WPD reveals an optical responsivity of 0.63-0.74 A/W at 1327.5 nm...

By using the generalized frequency division multiplexing (GFDM) and the machine learning algorithm for self-feedback amplitude/phase pre-distortion, the electro-absorption modulator integrated distributed-feedback semiconductor laser diode (EAM-DFBLD) is encoded with improved transmission quality and capacity. Both back-to-back (BtB) and 10-km sing...

A dual-mode (DM) vertical-cavity surface-emitting laser (VCSEL) is investigated for carrying high-speed data transmission with either the non-return-zero on-off keying (NRZ-OOK) or the quadrature amplitude modulation-orthogonal frequency division multiplexing (QAM-OFDM) format. In both the back-to-back (BtB) and the 100-m transmission cases with us...

By pre-emphasized encoding of a dual-mode 850 nm vertical-cavity surface-emitting laser (VCSEL), the nearly 70 Gbit/s on–off keying (OOK) transmission performance is performed for the ultrafast data link. This VCSEL is designed with a new structural configuration, including 6 μm oxidized aperture and 4 μm Zn-diffused emission aperture, which exhibi...

By collimating the single-mode (SM) vertical-cavity surface-emitting laser (VCSEL) at 850 nm with either the OM4 multi-mode fiber (OM4-MMF) or the graded-index single-mode fiber (GI-SMF) with lensed end-face, the directly encoded non-return-to-zero on-off keying (NRZ-OOK) data transmission performance is characterized when tilting the coupling angl...

A low-temperature plasma-enhanced chemical vapor deposition grown germanium (Ge) thin-film is employed as a nonlinear saturable absorber (SA). This Ge SA can passively mode-lock the erbium-doped fiber laser (EDFL) for soliton generation at a central wavelength of 1600 nm. The lift-off and transfer of the Ge film synthesized upon the SiO2/Si substra...

Photodetectors based on rGO have attracted much attention owing to their simple and low‐cost fabrication process. However, the aggregation and defects of rGO flakes still limit the performance of rGO photodetectors. Controlling the composition of reduced graphene oxide (rGO) has become a vital factor for its prospective applications. For example, t...

Directly modulated 850-nm multimode vertical-cavity surface-emitting lasers (MM-VCSELs) with different oxide apertures and transmission microstrip lengths are compared on the transmission performance of the non-return-to-zero on-off keying (NRZ-OOK) and four-level pulse amplitude modulation (PAM-4) data formats. In this work, intrinsic and extrinsi...

Under pulsed modulation, the emission uniformity in terms of pulsewidth and delay of a 940 nm multimode vertical‐cavity surface‐emitting laser (MM‐VCSEL) array is characterized by analyzing the position‐dependent pulsating and chirping dynamics among localized 600 VCSEL elements. In addition, the MM‐VCSEL array biased nearly threshold current (Ith)...

The non-tilting lensed-MMF/SMF coupling of tri-mode VCSEL with D factor of 14 GHz/mA 0.5 is demonstrated to provide root-mean-square linewidth of 0.66/0.54 nm and mode-partition-noise of -145/-140 dBc/Hz for error-free 62-/58-Gbit/s NRZ-OOK and 164-/140-Gbit/ s 16-QAM-OFDM transmission.

All-optical intensity modulator at 25 Gbps in silicon carbide-based Kerr switching with a nonlinear refractive index of 2.88×10 ⁻¹³ cm ² /W is demonstrated with an SNR of 5.6 dB and an ER of 11.8 dB.

The shifted power-to-voltage response and reduced on/off extinction ratio observed in uncooled Si waveguide intensity modulator can be pre-compensated with offsetting the DC bias to recover the bit-error-ratio from 8.3×10 ⁻³ to 9.4×10 ⁻⁹ under 60-Gbit/s NRZ-OOK.

Relative-intensity and mode-partition noises of 850-nm few-mode VCSEL manipulated by using different lensed SMF/MMF coupling schemes are performed to optimize the transmission performance.

Optical wireless HDMI transceiver using uncooled 12-mW violet laser diode as Tx with f -3dB =4GHz and p-i-n photodiode as Rx with f -3dB =7GHz is demonstrated to enable 26.4-Gbit/s 64-QAM OFDM data and 2K×1K HDMI (1080P@60fps) video transmission.

This study demonstrates a Zn-diffusion few-mode (FM) vertical-cavity surface-emitting laser (VCSEL) with a performance of the quasi-single-mode, SMSR over 20 dB. The VCSELs have a stable output power due to the larger oxide aperture because high-order transverse modes are suppressed through impurity-induced disordering of Zn-diffusion. The VCSEL ha...

Traditional visible light communication (VLC) via light-emitting diodes (LEDs) employs the on-off keying (OOK) modulation scheme. Even though optical frequency modulation has many advantages, it is hardly used for LED VLC because a high carrier frequency cannot be applied to the LED cavity due to the resistance-capacitance limit. Here, by monolithi...

A green 2 × 2 micro light-emitting diode (μ-LED) array with nanostructured grating patterns grown on a semipolar (20-21)-oriented gallium nitride (GaN) buffered layer on (22-43)-oriented sapphire substrate is specially transistor-outline can (TO-can) packaged with a sub-miniature-A (SMA) connector for high-speed data communication beyond 5 Gbit/s....

The developing progress on the structural design and data algorithms to enable the VCSELs for transmitting multiple complex data formats beyond 100-Gbit/s has been reviewed in this paper. Up to now, academic and industrial institutions still keep their research pace on studying how to improve the allowable data rate of various data formats carried...

An optical heterodyned 28-GHz carrier generation is demonstrated for synthesizer-free fifth-generation (5G) millimeter wave over fiber (MMWoF) link by using orthogonally polarized dual-mode vertical-cavity surface-emitting laser (VCSEL) as the frontend transmitter, and the power envelope detection is employed for self-heterodyne down-conversion of...

For compact ultrahigh‐power lighting and high‐speed optical wireless communication (OWC) purposes, the red/green/violet laser diodes (R/G/V‐LDs) moduled with specific Subminiature A (SMA) connectors are used for cold white‐light mixing and direct digital encoding. Even with hybridizing a high‐power yellow light‐emitting diode (LED) for high color‐r...

Chirp-dispersion and data transmission analyses of the multimode vertical-cavity surface-emitting laser (MM-VCSEL) with a 7.5-m oxide-confined aperture and a root-mean-square spectral linewidth of 1 nm is performed for intra-data-center application. For directly modulating the NRZ-OOK and the PAM-4 data streams, an optimized bias current of 17 mA a...

The all-optical cross-wavelength quadrature amplitude modulation orthogonal frequency-division multiplexing (QAM-OFDM) data switching in the silicon rich silicon carbide (Si-rich SiC) micro-ring (μ-ring) waveguide is demonstrated for the first time by using the two-photon absorption (TPA) induced free carrier absorption (FCA) process. With enlargin...

The multi-mode vertical-cavity surface-emitting lasers (MM-VCSELs) with different photonic crystal (PhC) designs in core and cladding regions are compared for transmitting the complex formatted QAM-OFDM data over 100-m OM5 multi-mode fiber (MMF). Among the designs with using flat core/cladding (denoting as Core <sub xmlns:mml="http://www.w3.org/199...

We fabricated tantalum pentoxide (Ta2O5) channel waveguides and used them to experimentally demonstrate higher-order mode supercontinuum (SC) generation. The Ta2O5 waveguide has a high nonlinear refractive index which was in an order magnitude of 10–14 cm2/W and was designed to be anomalously dispersive at the pumping wavelength. To the best of our...

Based on the use of a dual-wavelength controlled quasi-color-free laser diode (QCFLD) transmitter with either destructively interfered beating or single-sideband filtering after receiving at a remote node, the 100-km long-reach (LR) carrierless millimeter-wave over fiber (MMWoF) link with directly-encoded orthogonal frequency-division multiplexing...

Ultrathin amorphous Ge (α-Ge) film is synthesized as nonlinear saturable absorber to enable the femtosecond pulsation of erbium-doped fiber laser, which self-starts the fiber laser pulsation with nearly 700-fs pulsewidth at threshold pumping condition. Under high-gain condition, the α-Ge film with thickness of 17 nm exhibits the largest self-amplit...

Based on two weak-resonant-cavity Fabry–Perot laser diodes (WRC-FPLDs) with almost identical mode intervals, we propose and demonstrate experimentally, a chaotic communication system with switchable chaotic carrier wavelength. In such a scheme, a WRC-FPLD (called T-WRC-FPLD) subject to filtered feedback provided by a tunable optical filter (TOF) is...

A quad-mode optical carrier generated by mode-deviated injection-locking a vertical-cavity surface-emitting laser (VCSEL) at a beating frequency of 40 GHz is demonstrated for establishing a long-reach millimeter-wave over fiber (MMWoF) link, in which only one mode of the quad-mode optical carriers is modulated by the 16-quadrature amplitude modulat...

A low-power-consumption single-arm-driven silicon (Si) Mach-Zehnder modulator (MZM) operated at C-band ( $\lambda =1550$ nm) for non-return-to-zero on-off-keying (NRZ-OOK) transmission beyond 50 Gbit/s over 10-km single-mode fiber (SMF) and dispersion-shift fiber (DSF) is demonstrated to guarantee the IEEE 802.3bs standardized 400GBASE-FR8/LR8 ope...

We demonstrated transmission of 850-nm dual-mode VCSEL carried NRZ- OOK data at 53 Gbit/s over 100 m graded-index single-mode fiber through heterogeneous mode-field mismatched coupling from lensed MMF with 40% efficiency or 4dB loss.

Tantalum pentoxide (Ta2O5) is a promising material for optical waveguide applications of photonics integration due to its excellent linear and nonlinear optical properties, such as high refractive index, large bandgap, and high nonlinearity. The quality of thin film deposition will then be critical for realizing optical waveguide devices and module...

Visible light communication is an emerging high-speed optical wireless communication technology that can be a candidate to alleviate pressure on conventional radio frequency-based technology. In this paper, for the first time, the advanced modulation format of probabilistic shaping (PS) bit loading is investigated in a high data rate visible light...

Visible Light Communication (VLC) technology is an emerging technology using visible light modulation that, in the modern world, will mainly facilitate high-speed internet connectivity. VLC provides tremendous advantages compared to conventional radio frequency, such as a higher transmission rate, high bandwidth, low-power consumption, no health ha...

We propose and demonstrate experimentally a scheme for simultaneously generating multi-channel broadband chaotic signals based on two unidirectionally coupled weak-resonant-cavity Fabry-Perot laser diodes (WRC-FPLDs) with almost the same mode interval, where one WRC-FPLD is utilized as master WRC-FPLD (M-WRC-FPLD) and the other is used as slave WRC...

Single-mode VCSEL technology has advanced significantly in the past few years. The advantages of single-mode VCSELs lie primarily on the narrower linewidth, lower numerical aperture and smaller spot size compared to multimode VCSELs. They are suitable for transmitting over both multimode fibers and few-mode fibers. For multimode fiber systems, the...

The transmission performances of the tri-mode vertical cavity surface-emitting laser (VCSEL) carrying 16-quadrature amplitude modulation orthogonal frequency division multiplexing (16-QAM OFDM) data streams at a data rate beyond 100 Gbit/s are demonstrated in OM5 and OM4 multi-mode fibers (MMFs) over 100 m. By using the double oxide-confined apertu...

An eye-safe white-lighting source configured with violet laser diode (VLD) and an ultrafast color convertor using the BEHP-PPV+MEH-PPV polymer blend is demonstrated for optical wireless communication system. The BEHP-PPV+MEH-PPV polymer is a mixture of green emitter (BEHP-PPV) and red emitter (MEH-PPV) with a compositional ratio of 5:15 for obtaini...

A synthesizer-free 28-GHz millimeter wave (MMW) carrier is generated by using orthogonally polarized dual-mode vertical-cavity surface-emitting laser (VCSEL) as the frontend transmitter. After equalizing the dual modes with an extremely weak power as low as -26 dBm (2.5 W) at TM-mode polarization, the dual-mode power extinction of only 5.4 dB is ac...

This paper reviews the developing progress on the synthesis of the silicon quantum dots (Si-QDs) via the different methods including electrochemical porous Si, Si ion implantation, and plasma enhanced chemical vapor deposition (PECVD), and exploring their featured applications for light emitting diode (LED), color-converted phosphors, and waveguide...

To optimize the high-speed modulation package of the TO-can mounted violet laser diode (VLD) for optical wireless communication (OWC), three different impedance matching methods with adding or removing resistor/inductor/capacitor (R/L/C) elements are employed to discuss their effects on the direct encoding bandwidth of the VLD. With reducing the pa...

By remotely heterodyning two independent laser carriers, the long-reach 60-GHz millimeter-wave-over-fiber (MMWoF) link is demonstrated for the Volterra series filtered quadrature amplitude modulation orthogonal frequency division multiplexing (QAM-OFDM) transmission with nonlinear noise suppression, which enables 13-Gbps data delivery through 50-km...

The visible wavelength-division multiplexing (VWDM) optical wireless communication beyond 30 Gbit/s with a white-light beam mixed by red/green/violet (R/G/V) laser diodes (LDs) and yellow (Y) LED is demonstrated via quadrature amplitude modulation discrete multitone modulation (QAM DMT). To facilitate both high-quality indoor lighting and high-spee...

In this Letter, we report high-speed integrated 14 µm in diameter micro-light-emitting diode (μLED) arrays with the parallel configuration, including ${2} \times {2}$ 2 × 2 , ${2} \times {3}$ 2 × 3 , ${2} \times {4}$ 2 × 4 , and ${2} \times {5}$ 2 × 5 arrays. The small junction area of μLED ( ${\sim}{191}\;\unicode{x00B5}{\rm m}^2$ ∼ 191 µ m 2 ) in...

By enhancing the differential gain and reducing the capacitance of the 850-nm multi-mode vertical cavity surface emitting laser (VCSEL) with an analog bandwidth beyond 25 GHz via the use of InGaAs/AlGaAs quantum wells and multiple oxide confinement layers, the transmission of directly encoded 4-level pulse amplitude modulation (PAM-4) data at 42 GB...

Beyond 100-Gbit/s/λ high-speed inter-data-center link composed by hybridly integrated electro-absorption modulator (EAM) and distributed feedback laser diodes (DFBLD) based transmitter at 1306 nm, and received by a PIN-PD+TIA optical receiver is demonstrated to carry 104-Gbit/s pre-emphasized PAM-4 data for 2-10 km single mode fiber (SMF) propagati...

A comprehensive comparison on the data transmission performance of photonic crystal structured micro light-emitting diodes (PC-µLEDs) with different aperture sizes is realized for high-speed visible light communication application. The 120×120-µm² large PC-µLED exhibits the largest optical power of 580 µW and the highest external quantum efficiency...

Miniature white-lighting beam mixed by R/G/V-LDs+Y-LED module with high illuminance of 12800 lux, high color-rendering-index of >60 is demonstrated for vehicle light fidelity or distant optical wireless lighting transmission at data rate beyond 20 Gbps.

A red/green/violet-LD and yellow-LED based four-color white-lighting module is employed for free-space visible wavelength division multiplexing (VWDM) data transmission at 30 Gbps with using the bit-loaded discrete multi-tone (DMT) data format.

The 850-nm multimode VCSEL designed with dual-oxide-layer confined 7.5-um-large aperture and doped DBR shortened RC response improves its modulation linearity to 0.3±0.1- mW/mA for 61-Gbps NRZ-OOK, 102-Gbps PAM-4 and 124-Gbit/s 32-QAM GFDM data transmissions.

Remote heterodyne of incoherent dual laser carriers enables local-oscillator-free 60- GHz MMWoF link for delivering 10-Gbit/s 16-QAM OFDM data over 25-km single-mode-fiber and 3-m free-space with 1.7-dB signal-to-noise ratio enhancement via Volterra series nonlinear noise compensation.

Beyond 150-Gbit/s single-arm modulation of a waveguide-type silicon Mach-Zehnder interferometer (MZI) modulator operated at 1550 nm is achieved by using the GFDM data stream with optimizing K subcarriers and M time slots.

We proposed a frequency slicing pre-equalization scheme for laser diode based underwater visible light communication. An AIR increment of beyond 1 Gbps was achieved when signal suffers from great attenuation at the high frequency region.

This paper emphasizes on overviewing the developing progress of the state-of-the-art carbon nanomaterial based satuable absorbers for passively mode-locked fiber lasers, including carbon nanotube (CNT), graphene, graphite and other carbon nanomaterials. With reviewing the performances of these proposed candidates, the characteristic parameters requ...

The TE/TM-mode spectral-separated C-rich SiC ring waveguide is employed to demonstrate polarization-dependent amplitude/polarization shift keying (ASK/PolSK) “AND“ logic gate. The plasma-enhanced chemical vapor deposition-grown C-rich SiC film exhibits a nonstoichiometric SiC nano-cluster phase structure with a C/Si atomic ratio of 1.28, which prov...

By color-converting the violet laser diode (VLD) with a cadmium selenide and zinc sulfide (CdSe/ZnS) core-shell-quantum dot (QD) doped polydimethylsiloxane (PDMS) film, the VLD + CdSe/ZnS core-shell-QD transferred white-light with improved color rendering index (CRI) is demonstrated for high-speed indoor visible lighting communication. To facilitat...

Based on the pre-emphasis 4-level pulse amplitude modulation (PAM-4) format at a symbol rate of 32 GBaud, the comparisons among optical PAM-4 data transmissions through back-to-back (BtB), 100-m OM4 multi-mode fiber (MMF), and 100-m OM5-MMF links are discussed in detail by employing the directly modulated few-transverse-mode (FM) vertical cavity su...