A novel diffraction grating based on arrayed channel waveguides has been proposed for nanometre-spaced wavelength division multiplexing. with a order of 20 fabricated using composite glass waveguide. resolution 0.63 nm achieved in the 1.3 μm band.

The two main trends in the progress of ultrawide-band/high-frequency photodetectors (PD's), improving bandwidth-efficiency product and obtaining a high saturation current, are reviewed. With respect to achieving large bandwidth-efficiency, limiting factors potentials edge-coupled (waveguide, waveguide-fed, traveling-wave, periodic-traveling-wave), resonant-cavity, refracting-facet photodiodes, as well avalanche photodiode discussed. Regarding high-saturation author estimated how much...

Silica-based planar lightwave circuits (PLC) provide various important devices for both optical wavelength-division-multiplexing networks and access network. This paper is an overview of recent progress in PLC technology including power splitters, arrayed-waveguide gratings, thermooptic switches, hybrid integrated PLC's.

A mushroom-mesa structure is proposed to reduce the CR-time constant which originates from waveguide photodiode structure. Experimental results at a 1.55-μm wavelength show that multimode p-i-n with has an electrical 3-dB bandwidth of more than 75 GHz in frequency domain and 110 time domain. The external quantum efficiency 50% or 0.63 A/W, leads record bandwidth-efficiency product 55 for long photodetectors.

A side-illuminated p-i-n photodetector with a multimode waveguide structure is proposed. Numerical and experimental results show that higher-order mode lights greatly enhance the coupling efficiency between (WGPD) fiber, which leads to high external quantum efficiency. The WGPD has major advantage bandwidth can be derived independently of each other because designed without deteriorating electrical properties. fabricated an 56% AR coating 68% coating, frequency 3 dB greater than 50 GHz at...

We propose a new beam scanning model that is applicable to electrooptic materials with electron traps. With this model, we can achieve both high-speed operation and wide-angle scanning, because the operating speed limited not by mobility but frequency limit of effect materials. The voltage dependence angle at 100 kHz using KTa1-xNbxO3 crystal consistent property predicted proposed model.

We developed a thermo-optic effect based silica optical phased array (OPA) chip and evaluated its tunability of phases lightwaves. The THz waves, whose are controlled by the OPA chip, generated from four arrayed uni-travelling-carrier photodiodes (UTC-PDs) on heterodyne photomixng. Meanwhile, UTC-PDs, which integrated with 4×4 slot antennas, fabricated monolithic InP substrate for 300-GHz wave beam combining steering. Through optoelectronic THz-wave phase control, feasibility continuous...

In this study, generating and enhancing THz continuous/pulsed waves is achieved by fabricating a monolithic InP substrate chip of arrayed photomixers, where each photomixer includes an InP/InGaAs uni-traveling-carrier photodiode (UTC-PD) with integrated 1 × 4 planar slot antennas (PSAs). Through optoelectronic time-aligned -gradient delays lightwaves that couple to the radiated yield both quantitative gain spatial directional gain. To generate continuous 300 GHz waves, UTC-PD excited at...

Abstract We explored the potential of an optoelectronic frequency hopping system within 300 GHz band, leveraging a tunable distributed feedback laser array and uni-traveling carrier photodiode. Our experiments successfully achieved 10-channel terahertz (THz) hopping, marking significant advancement in THz secure communication technologies. Notably, exhibited rapid frequency-hopping capability with short transition time 0.8 ms between channels, ranging from 288 to 331 GHz. Further, we...

A photomixing-based frequency-hopping spread spectrum (FHSS) system is effective for future secure terahertz (THz) wireless communications. Conventional photomixing systems are typically composed of two lasers, which result in an increased size and power consumption. To address this issue, we applied our proposed THz wave generation method, using a single wavelength-tunable laser, to the FHSS system. In experiments, successfully demonstrated J-band (220–330 GHz) with frequency-hopped interval 400 ns.

Silica-based planar lightwave circuit (PLC) hybrid integration is a promising way to provide highly functional photonic components. This paper an overview of recent progress in PLC technology including optoelectronic semiconductor devices for the integration, various wavelength-division multiplexing, and all-optical time-division multiplexing.

The first wideband tellurite-based Raman fibre amplifier is described. provided a 160 nm bandwidth with gain of over 10 dB and noise figure below from 1490 to 1650 only 250 m in length pumped by 4 wavelength channel LDs.

The burst-mode 3R receiver using monolithic ICs for 10-Gbit/s-class optical access networks is reported. In a point-to-multipoint system like passive network (PON), the at line terminal (OLT) must be able to handle packets with significantly different powers and phases. An OLT high sensitivity instantaneous response burst inputs desired widening accommodation area efficiency in PON uplinks. Currently, diffusion of high-speed Internet connection services represented by fiber home 1.25 Gbit/s...

A hollow‐waveguide‐output uni‐travelling‐carrier photodiode (UTC‐PD) module operating at frequencies from 400 to 900 GHz has been developed. The consists of a UTC‐PD, photodiode‐to‐waveguide coupler, and metallic package with waveguide rectangular (WR)‐1.5 waveguide. coupler is monolithically integrated the UTC‐PD chip. fabricated exhibits output power as high −19 dBm 500 3 dB bandwidth 340 GHz, which widest among ever‐reported modules.

Beam forming and beam steering are inevitable technologies for the practical application of high-frequency electromagnetic waves. Specifically, control technology using a phased array terahertz waves above 100 GHz is necessary to realize future high-speed wireless communication. By photomixing, which promising method generating waves, phase generated can be tuned in optical domain, so that from controlled by photonics technologies. Directing wave enables communication improved not only via...

A two-step bonding technique for optical device assembly on a planar lightwave circuit platform was developed, which consists of chip-by-chip thermo-compression prebonding step and simultaneous reflow step. The used to realize multichip integration the platform. characteristics were examined by investigating its strength accuracy. accuracies in horizontal vertical directions 1.1 0.8 /spl mu/m, respectively, with high strength. first applied 3 chip integrated transceiver module 136 fabricated...

There has been a growing interest in the application of terahertz (THz) waves to broadband wireless communications. Particularly, use THz at frequencies above 275 GHz is one big concerns among researchers, because these frequency bands have not yet allocated for specific active services, and there possible opportunity utilize extremely large bandwidths ultra-broadband In this paper, we describe photonics-based approaches realizing most practical robust 300-GHz-band links meet explore...

The photomixing of two lightwaves is one the promising methods generating a terahertz (THz) wave. conventional system consisting lasers and modulator results in large transmitter volumes high power consumption. To solve this issue, we devised novel THz wave generation modulation based on using single wavelength-tunable laser combination with delayed self-multiplexing. We successfully demonstrated feasibility 300-GHz modulation.

We proposed a photonic frequency-hopping physical-secure Terahertz-wave communication system driven by high-speed wavelength tunable laser and photomixer, experimentally demonstrated time of less than 25 ns at 300-GHz band.

An improved 8/spl times/8 optical matrix switch was fabricated using silica-based planar lightwave circuits (PLCs) on a silicon substrate. Three improvements were made. First, the waveguide material changed from titanium-doped silica (SiO/sub 22/-TiO/sub 2/) to germanium-doped 22/-GeO/sub reduce propagation loss. Second, offset driving powers supplied every unit realize high extinction ratios. Third, dummy units modified suppress crosstalk through these units. The average insertion loss of...

A uni-travelling-carrier structure is applied to the high speed, efficiency waveguide pin photodiode with aim of increasing maximum available output voltage. With a 50 Ω load, having an external quantum 32% yields voltage 1.3 V bandwidth 55 GHz, and 0.45 70 GHz.