Akio Furukawa

A low-loss, compact wide-FSR-AWG using SiON planar lightwave circuit technology

Wide FSR of 80 nm with SiON high-/spl Delta/ technology reduced loss variation among channels of a 40-channel AWG to 0.6 dB with low insertion-loss of less than 2.2 dB for all channels without chip-size enlargement.

Ultrahigh-speed all-optical data regeneration and wavelength conversion for OTDM systems

The latest results in ultrafast data regeneration and wavelength conversion with SMZ-type all-optical semiconductor switches are reviewed. In these operations, the SMZ-type switch is driven by random data pulses. The fastest bit rate reported to date for such input-data-driven all-optical operation has reached 168 Gb/s. With these all-optical devices, we may be able to build 160-Gb/s OTDM nodes for packet communications systems in the near future.

Control scheme for optimizing the interferometer phase bias in a symmetric-Mach-Zehnder-type all-optical switch

A control scheme for accurately optimizing (and also automatically stabilizing) the interferometer phase bias of symmetric-Mach-Zehnder (SMZ)-type ultrafast all-optical switches is proposed. In this control scheme, weak continuous-wave light is used as supervisory input light and its spectral power ratio at the switch output is used as a bipolar error signal. Our experimental results for 168-Gb/s 16:1 demultiplexing with a hybrid-integrated SMZ switch indicate the feasibility and the sensitivity of this control scheme.

Ultrafast optical signal processing with hybrid-integrated symmetric Mach-Zehnder all-optical switches

We report on various types of ultrafast all-optical signal processing with hybrid-integrated Symmetric-Mach-Zehnder (HI-SMZ) all-optical switches driven by 40-Gb/s or 40-GHz optical pulses. To operate HI-SMZ switches with such high-repetition excitation, we use longer semiconductor optical amplifiers (SOAs) as nonlinear phase shifters than we previously used. We demonstrate that extending the SOA length is useful for increasing carrier injection and thus enhancing the nonlinear phase shift in SOAs. We show 3R regeneration and wavelength conversion at 42 Gb/s using HI-SMZ switches with longer SOAs. We also show error-free optical demultiplexing of 168- or 336-Gb/s signal pulses with HI-SMZ switches driven by 42-GHz control pulses.