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We have achieved a silica-based PLC thermooptic switch with a power consumption of only 30 mW without any deterioration in the optical properties by using a tapered narrow ridge structure. To reduce the power consumption further, we propose a novel structure, the suspended narrow ridge structure, which has the advantages of both the tapered narrow ridge structure and the already reported suspended-bridge structure. As a result, we achieved PLC-VOA/switches with excellent heat design flexibility and a power consumption of 20 mW. In addition, using the proposed the suspended narrow ridge structure, we demonstrate a 16-channel V-AWG with a compact size of 20 times 17 mm and a low total power consumption of 320 mW. [ABSTRACT FROM PUBLISHER]

In this paper, an optical-signal-processing device mainly designed for time-slot switching is demonstrated. The device is composed of variable delay-line arrays fabricated by planar lightwave circuit technology and high-speed optical gates. The variable delay-line arrays consist of transversal-form or lattice-form optical circuits. The operating principle is based on serial-to-parallel conversion, adjustment of the delay time between the parallel signals, and the gating of the optical bits or packets in the optical region. The device does not require any interaction between lightwaves through optical nonlinear effects or filter banks for code matching. As an example of its operation, label-processing functions are demonstrated, specifically the label swapping of optical return-to-zero pulses. The merits of the proposed device are described and problems that must be solved are also discussed. [ABSTRACT FROM PUBLISHER]

We demonstrate an integrated-optic encoder/decoder for time-spreading/wavelength-hopping optical code division multiple access. It is composed of a wavelength multi/demultiplexer and variable delay lines fabricated by using silica-based planar lightwave circuit technology. We evaluated the device characteristics, including those of the key components and the encoding/decoding operation, and confirmed its flexible code assignment ability and good auto/cross correlations. We then tested the performance of the encoder/decoder by undertaking bit error rate measurements with 10-Gb/s pseudorandom binary sequence signals and confirmed its applicability to optical layer multicast routing and its ability to compensate for bit skew caused by fiber chromatic dispersion. [ABSTRACT FROM PUBLISHER]

Current and wavelength characteristics for 1.55-μm semiconductor optical amplifiers (SOAs) containing bulk active layers with various tensile strains were investigated. The strain dependence of the gain-difference between the TE-mode and TM-mode (ΔGTE-TM ) was almost linear having a waveguide-width over 0.8-1.5 μm. A -0.12% tensile-strained bulk SOA had very low ΔGTE-TM of less than 0.8 dB for driving current ranging from 0 to 120 mA. The low-polarization-sensitive condition of SOAs with strained-bulk active layers was shown to yield very wide range in driving current and wavelength for network device applications [ABSTRACT FROM PUBLISHER]

We propose and demonstrate a very low insertion loss silica-based arrayed-waveguide grating (AWG) achieved using a novel structure, which has vertically tapered waveguides between arrayed-waveguides to reduce the slab-to-arrayed-waveguide transition loss. A spot-size converter is also incorporated in the AWG to reduce the fiber-to-waveguide coupling loss. The structure can be formed by a process involving the conventional photolithography and reactive ion etching. The structure provided a loss reduction of 1.5 dB. Moreover, we have successfully obtained a minimum insertion loss of 0.75 dB with a crosstalk of -40 dB and polarization-independent operation [ABSTRACT FROM PUBLISHER]