Kenji Nishide

Novel long-period fiber grating using periodically released residual stress of pure-silica core fiber

Summary form only given. Long-period fiber gratings (LPFGs) are promising components in optical fiber communications. The LPFG is usually fabricated by photo-refractive effect using an UV-laser or by fiber deformation by local heating methods. In this report, we propose a new technique for fabricating an LPFG by local heating of a pure-silica core fiber to release residual stress of a core without fiber deformation.

PDL reduction of long-period fiber grating by rotating exposure method

We propose a novel fabrication method to suppress polarization dependent loss (PDL) of long-period-fiber gratings by a rotating exposure technique, with a theoretical consideration of the PDL origins of long-period fiber gratings.

Optical Camera Link cable for the industrial applications

We present the development of an active optical cable (AOC) for the Camera Link interface, in which our compact optical assembly structure has been applied. The optical Camera Link cable enables the transmission of a high resolution image more than 10 m which has been the maximum transmission length for conventional metal cables.

Precise determination of local birefringence of optical fibers by long-period fiber grating analysis

We have proposed a novel and precise technique to determine the local birefringence of optical fibers by writing an LPFG in the fiber to be evaluated and analyzing the transmission loss and PDL of the LPFG. The accuracy of the determined local birefringence has been confirmed to be approximately 10/sup -8/, which is about 100 times better than the existing methods.

Athermalization of wideband EDFA gain profile using a phase-shifted long-period fiber grating

An EDFA gain profile was athermalized passively using a phase-shifted long period fiber grating with low background loss of 0.9 dB. Gain variation was suppressed to 0.25 dB/sub pp/ in the temperature range of 0-65/spl deg/C over 40 nm of C-band with 2.1 dB gain.

Is Silicon Photonics a Competitive Technology to Enable Better and Highly Performing Networks

This chapter focuses on the fundamental and high-speed characteristics of small-footprint integrated optical modulators designed and fabricated on the basis of the silicon-photonic platform to assess their key performance factors in applications related to high-capacity energy-efficient optical networks transmitting data in various modulation formats. The design and characteristics of high-speed silicon rib-waveguide phase shifters, which are most essential in the high-speed optical modulators, are described. A low-loss quasi-single-mode silicon rib-waveguide phase shifter with reduced RC delay is highlighted along with its design features and fundamental performances in terms of optical loss and on/off dynamic response. Free-carrier plasma dispersion is reviewed as a physical process for performing optical modulation, which allows a reduction in thermal drift and frequency chirping. The plasma dispersion has a unique property in that signal distortion due to residual intensity modulation cancels with the nonlinear voltage dependence of the optical phase, thereby being useful for zero-chirp optical modulators to eliminate transmission impairments. The on-off keying performance of a silicon optical modulator using a single Mach–Zehnder interferometer waveguide is described in the first example of optical network applications with emphasis on a 10-Gb/s dispersion tolerance comparable to that of a commercial lithium niobate modulator. The advantage of silicon-photonic integration is remarkable, in particular, for the ultrasmall-footprint silicon optical modulator consisting of a pair of IQ nested Mach–Zehnder interferometers for two orthogonal polarization components and a polarization multiplexer monolithically integrated on a silicon chip. Such a chip is presented with respect to applications in digital coherent communication in optical-fiber links up to 1000 km long at a bit rate as high as 128 Gb/s.

Ultralow PDL WDM fiber couplers for WDM transmission systems

Summary form only given. We have presented the polarization-swapping method as a polarisation dependent loss (PDL) reducing technique for fused taper fiber couplers. The manufactured 1.48/1.55 /spl mu/m WDM fiber couplers have shown a small PDL of one tenth of that of conventional couplers. This technique is very useful to reduce the PDL of WDM fiber couplers for EDFAs in WDM fibre transmission systems.

Low loss all-PANDA-fiber polartization beam splitter/combiner

A low loss all-fiber polarization beam splitter/combiner (AF-PBS/C) is proposed. Achieved insertion losses of slow and fast axis were as low as 0.1 dB and 0.3 dB, respectively. Crosstalk was less than -25dB. High reliability was also confirmed.

Effect of an additional ring profile on transmission characteristics of 1.55-µm dispersion-shifted fibers

Various types of 1.55-μm dispersion-shifted fiber have been presented. Among them, triangular core1 and similar fibers have the advantage in terms of optical loss. Recently, a triangular profile with a ring in the cladding was proposed to minimize the bending loss.2 Our paper now describes the effect of the ring on the transmission characteristics of triangular and Gaussian core fibers.3