It was observed that bi-directional phase changes can be triggered by genuine photoexcitation between two phases with different bond structures in polydiacetylenes. The photoinduced transition found to mediated photogeneration of charge carriers (and not excitons). extremely high efficiency is perhaps due cooperative interaction the locally photoconverted domains.

We observe coherent resonant coupling of optical whispering-gallery modes in fluorescence from dye doped polymer bispheres with diameters ranging 2 to $5\ensuremath{\mu}\mathrm{m}$. By monitoring the frequencies peaks individual spheres, we sort out two spheres appropriate size matching and bring them into contact. Wave optics calculation also gives good agreement experiment. taking account harmonic modes, obtained features normal mode splitting are well explained by tight-binding photon picture.

Lasers with ultra-low operating energy are desired for use in chip-to-chip and on-chip optical interconnects. If we to reduce the energy, must active volume. Therefore, a photonic crystal (PhC) laser wavelength-scale cavity has attracted lot of attention because PhC provides large Q-factor small To improve this device's performance, employ an embedded region structure which is buried InP slab. This enables us achieve effective confinement both carriers photons, thermal resistance device....

We describe the growth of InP layer using an ultrathin III-V active that is directly bonded to SiO₂/Si substrate fabricate a buried heterostructure (BH) laser. Using 250-nm-thick layer, we succeeded in fabricating BH distributed feedback (DFB) laser on substrate. The use lateral current injection structure important for forming p-i-n junction thin film. fabricated DFB modulated by 25.8-Gbit/s NRZ signal at 50°C. These results indicate our fabrication method promising way high-efficiency...

We have developed a wavelength-scale embedded active-region photonic-crystal laser using lateral p-i-n structure. Zn diffusion and Si ion implantation are used for p- n-type doping. Room-temperature continuous-wave lasing behavior is clearly observed from the injection current dependence of output power, 3dB-bandwidth peak, wavelength. The threshold 390 μA estimated effective 9.4 μA. power in waveguide 1.82 μW 2.0-mA injection. These results indicate that structure effectively reduce thermal...

To cope with the various nonlinear signal distortions in intensity-modulation/direct-detection transmission systems, a theoretical analysis on Volterra equalizer (VNLE) is provided, focusing computational complexity aspects. The yields simple reduced-complexity scheme for second-order VNLE (R2-VNLE) based performance-complexity tradeoff. An experimental verification performed single-sideband 28-GBaud PAM-4 signals, generated by an electroabsorption modulated distributed-feedback laser, over...

Third-order harmonic generation has been measured on highly oriented polydiacetylene (PDA) films prepared by the vacuum deposition method. Experimental values of third-order electric susceptibility χ(3) for pumping laser polarized parallel to polymer chain show a sharp three-photon resonance 1Bu exciton in PDA. Potential usefulness these PDA evaporated nonlinear optical applications is suggested.

The power consumption of a conventional photoreceiver is dominated by that the electric amplifier connected to photodetector (PD).An ultralow-capacitance PD can overcome this limitation, because it generate sufficiently large voltage without an when combined with high-impedance load.In work, we demonstrate ultracompact InGaAs based on photonic crystal waveguide length only 1.7 μm and capacitance less than 1 fF.Despite small size device, high responsivity A/W clear 40 Gbit/s eye diagram are...

The introduction of the photonic crystal (PhC) wavelength-scale cavity as a laser enables us to obtain both ultralow threshold current and operating energy. These parameters are essential when using transmitters in chip-to-chip on-chip interconnections. To improve device performance, we employ an ultracompact embedded active region that call lambda-scale active-region PhC or LEAP laser. We have developed electrically driven laser, which operates under room-temperature continuous-wave...

The cost and power consumption of optical transmitters are now hampering further increases in total transmission capacity within between data centers. Photonic integrated circuits (PICs) based on silicon (Si) photonics with wavelength-division multiplexing (WDM) technologies promising solutions. However, due to the inefficient light emission characteristics Si, incorporating III-V compound semiconductor lasers into PICs via a heterogeneous integration scheme is desirable. In addition,...

The authors have developed a new heterogeneous-integration method for fabricating semiconductor lasers with high modulation efficiency on Si substrates. employs the direct bonding of an InP-based active layer to SiO2 thermally oxidised substrate (SiO2 /Si substrate), followed by epitaxial growth InP form buried heterostructure (BH). By using membrane, realise membrane directly bonded without crystal quality degradation. Both theoretical estimation and photoluminescence measurements revealed...

Controlling gain and loss of coupled optical cavities can induce non-Hermitian degeneracies eigenstates, called exceptional points (EPs). Various unconventional phenomena around EPs have been reported, are expected to incorporate extra functionalities into photonic devices. The eigenmode exactly under EP degeneracy is also predicted exhibit enhanced radiation. However, such responses yet be observed in on-chip lasers because both the limited controllability their lifting by pump-induced...

There has been an increasing need for small, low-cost, and low-power consumption optical transceivers short-reach fiber links. Waveguide-integrated photodetectors (PDs) with wide bandwidth high responsivity on Si photonics platforms are essential element these applications. We have fabricated O-band membrane PD which is suitable integration high-performance III-V-based devices such as lasers modulators, passive waveguide circuits the platforms. The consists of InGaAsP-bulk absorption core...

We observed laser emission in whispering gallery modes using a microring composed of semiconducting polymer poly[2,5-bis-(2′-ethylhexyloxy)-p-phenylenevinylene coated on an etched fiber under transient and quasisteady-state pumping conditions. The threshold for oscillation was 1 mJ/cm2 (0.1 MW/cm2) 30 μJ/cm2 (300 nanosecond femtosecond excitation, respectively. output showed superlinear dependence the excitation energy above threshold. demonstration lasing shows possibility to develop...

High demand exists for low operating energy optical links that use wavelength division multiplexing technologies in datacenter networks. Thus, we fabricate a directly modulated membrane distributed-reflector laser with on thermally oxidized silicon (Si) substrate. Because epitaxial growth to bury an active region bonded InP-based membrane, it needs be kept within critical thickness, which is related the temperature and thermal expansion coefficients of materials. In previous studies, used...

We demonstrate the continuous-wave operation of lambda-scale embedded active-region photonic-crystal (LEAP) lasers at room temperature, which we fabricated on a Si wafer. The on-Si LEAP exhibit threshold current 31 μA, is lowest reported value for any type semiconductor laser Si. This reveals great potential as light sources on- or off-chip optical interconnects with ultra-low power consumption in future information communication technology devices including CMOS processors.

Buried multiple-quantum-well (MQW) 2D photonic crystal cavities (PhC) achieve low non-radiative recombination and high carrier confinement thus making them highly efficient emitters. In this study, we have investigated the lasing characteristics of high-β(spontaneous emission coupling factor) buried MQW nanocavity lasers to clarify theoretically-predicted thresholdless operation in high-β nanolasers. The strong light our nanolasers enabled us clearly demonstrate very smooth transition terms...

We demonstrate monolithic integration of a 50-μm-long-cavity membrane distributed-reflector laser with spot-size converter, consisting tapered InP wire waveguide and an SiOx waveguide, on SiO2/Si substrate. The device exhibits 9.4-GHz/mA0.5 modulation efficiency 2.2-dB fiber coupling loss. 25.8-Gbit/s direct bias current 2.5 mA, resulting in low energy cost 132 fJ/bit.

Reducing the operating energy of a distributed feedback (DFB) laser is critical issue if we are to use device as directly modulated light source employing wavelength division multiplexing technologies in short-distance datacom networks. A membrane buried heterostructure (BH) DFB on SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> layer one candidate for reducing because it provides strong carrier and optical confinement active region....