Ikuo Ogawa

160-Gb/s OTDM transmission using integrated all-optical MUX/DEMUX with all-channel modulation and demultiplexing

This letter provides the first report of 160-Gb/s optical time-division-multiplexed transmission with all-channel independent modulation and all-channel simultaneous demultiplexing. By using a multiplexer and a demultiplexer based on periodically poled lithium niobate and semiconductor optical amplifier hybrid integrated planar lightwave circuits, 160-km transmission is successfully demonstrated.

Optical packet synchronizer using wavelength and space switching

The authors develop and demonstrate an optical packet synchronizer. Synchronization with a time resolution of 16 ns is achieved by selecting one of 64 optical paths, each with a different length, using wavelength and space switching based on a tunable distributed Bragg reflector laser diode and eight semiconductor optical amplifier gates per channel. Asynchronous optical packet signals are successfully aligned in a series of common time slots.

High-speed 32-channel optical wavelength selector using PLC hybrid integration

We have developed a new high-speed 32-channel optical wavelength selector (OWS) with gate drivers using PLC hybrid integration. It has excellent characteristics consisting of a low insertion loss of 2.3 dB, a low cross talk of -46 dB and the error-free optical wavelength selection of 10-Gbit/s optical signal.

Silica-based integrated planar lightwave true-time-delay network for microwave antenna applications

Summary form only given. The authors have developed a fully integrated controllable true-time-delay (TTD) network using silica-based planar lightwave circuits (PLCs) which have the characteristics of low loss (0.1 dB/cm or less), far easier polarization maintenance, patterning flexibility (the minimum radius is 2 mm when /spl Delta/ is 1.5%), and active circuit capability through the thermo-optic effect. Experimental results show that the proposed TTD networks will be excellent candidates for microwave antenna applications.

Reduction of waveguide facet reflection in optical hybrid integrated circuit using saw-toothed angled facet

A saw-toothed facet structure is proposed to reduce the waveguide facet reflection in an optical hybrid integrated circuit. This structure was used to achieve the hybrid integration of a semiconductor laser amplifier (SLA) on a planar lightwave circuit (PLC) platform. Gain ripple for a flat facet was reduced from 3.6 dB to 0.6 dB by setting a facet angle of 35 degrees. The SLA insertion loss was 3.5 dB at 0 degrees and 4.0 dB at 35 degrees with an SLA injection current of 80 mA. Thus the sawtoothed facet is confirmed to reduce facet reflection effectively without significant insertion loss increase.<<ETX>>

An application of a silica-on-terraced-silicon platform to hybrid Mach-Zehnder interferometric circuits consisting of silica-waveguides and LiNbO/sub 3/ phase-shifters

By using a silica-on-terraced-silicon platform (STS-platform) for optical hybrid integration, we fabricated a hybrid Mach-Zehnder interferometric circuit consisting of silica-waveguide directional couplers and a LiNbO/sub 3/ phase-shifter array. The circuit functioned as an optical switch with an insertion loss of 6.0 dB including input and output fiber coupling loss and an extinction ratio of better than 20 dB. The STS-platform was thus confirmed to incorporate both a high-performance planar lightwave circuit and a silicon optical bench.<<ETX>>

Highly Stable 160-Gb/s OTDM Technologies Based on Integrated MUX/DEMUX and Drift-Free PLL-Type Clock Recovery

This paper reports 160-Gb/s optical time-division-multiplexed (OTDM) technologies including an all-optical integrated multiplexer (MUX) providing all-channel independent modulation, an all-optical integrated demultiplexer (DEMUX) that offers all-channel simultaneous demultiplexing, and a drift-free phase-locked-loop (PLL)-type clock recovery circuit for ultrahigh-speed OTDM signals. We present the configuration of each technology and the results of experiments on those technologies. Highly stable operation is successfully demonstrated by using a MUX based on periodically-poled lithium niobate (PPLN) hybrid integrated planer lightwave circuit (PLC), a DEMUX based on semiconductor optical amplifier hybrid integrated PLC, and clock recovery circuit based on a PLL with an optical phase modulator and a PPLN waveguide

Ultrasmall 100 GHz 40-Channel VMUX/DEMUX Based on Single-Chip 2.5%-

The extension of optical add/drop multiplexing (OADM) systems to metro-core and metro-access networks has led to the need for economical and compact OADM devices. In this paper, we demonstrate a 1-in.2 100 GHz spacing 40-channel (ch) single-chip variable attenuator multiplexer/demultiplexer based on a monolithic 2.5%-Delta silica planar lightwave circuit (PLC) and stacked photodiode arrays. We also investigate the particular issues raised by monolithic integration with such high Delta waveguides. One is the loss increase caused by high index contrast of the waveguides. Performance fluctuation and thermal interference between the integrated circuits are also inherent issues. By utilizing effective solutions, we have successfully overcome such problems and confirmed that a 2.5%-Delta silica PLC is effective for use in monolithic integration.

\Delta

We developed a compact 16-ch optical wavelength selector (OWS). Our OWS is composed of two arrayed-waveguide gratings (AWGs) and an optical gate array (OGA) integrated on a single PLC platform by using the hybrid integration technique. We successfully obtained lossless operation with an extinction ratio of better than -45 dB for all wavelength channels. We also obtained a switching time of less than 1 ns. These excellent characteristics are the same as those of a previously reported OWS fabricated using PLC-PLC direct attachment.

PLC

We report a compact receiver optical sub-assembly (ROSA) for 100GbE CFP4 transceivers. All the four channels of fabricated module exhibits wide wavelength passband and high receiver sensitivity enough for 10-km-reach transmission.