Kenya Suzuki

Monolithically integrated resonator microoptic gyro on silica planar lightwave circuit

We report a novel configuration of resonator microoptic gyro (MOG), which is monolithically integrated on silica planar lightwave circuit (PLC) with countermeasures for noise factors. Optical ring-resonator gyros suffer mainly from polarization fluctuation induced noise and backscattering induced noise. We discuss eigenstate of polarization in the waveguide to clarify behavior of the former and propose a countermeasure with control of the waveguide birefringence. As for the latter, binary phase shift keying (B-PSK) with a special signal processing is proposed. Thermooptic (TO) phase modulation is the only one scheme to apply B-PSK in the silica waveguide, whose bandwidth is limited to /spl sim/1 KHz. To utilize the narrow bandwidth of the TO modulator effectively, we propose an electrical signal processing scheme and a modulation waveform to compensate the frequency response. By constructing an experimental setup, suppression of the backscattering induced noise is demonstrated, and the gyro output is observed with applying an equivalent rotation.

Adaptive dispersion slope equalizer using a nonlinearly chirped fiber Bragg grating pair with a novel dispersion detection technique

We realized the first adaptive-dispersion equalizer that equalizes dispersion over a wide wavelength range (6 nm) in the zero-dispersion wavelength region of a dispersion-shifted fiber (DSF). The equalizer is based on a pair of nonlinearly chirped fiber Bragg gratings, which are designed to equalize exactly the dispersion profile of a DSF. The dispersion changes were tracked using a technique that employs opposite dispersion fibers to identify the sign of the dispersion change. Unlike previous approaches, no additional sources or changes in the source wavelength are required. We demonstrate the adaptive equalization of the dispersion changes in an 83-km DSF, induced by temperature changes between -10/spl deg/C and 60/spl deg/C.

3.2-5 Gb/s, 100 km error-free soliton transmission with erbium amplifiers and repeaters

For the transmissions, the transform-limited soliton pulse source is a gain-switched distributed-feedback laser diode with a narrowband spectral filter and erbium amplifiers. A LiNbO/sub 3/ light intensity modulator is used for pulse switching. The preemphasis technique for sending solitons over a long distance, in which an erbium optical repeater is installed every 25 km as a lumped amplifier, is used.<<ETX>>

The modulation instability laser. II. Theory

For pt.I see ibid., vol.25, no.9, p.2036-44 (1989). A general analysis of the modulation instability laser (MIL) in a nonlinear dispersive cavity is presented. The theory of the feedback-induced modulational instability is derived. By introducing the pump depletion within one circulation of the pump pulse, the steady-state MIL oscillation can be predicted. The ripple frequency is equal to the modulation instability frequency. >

Low-loss, 2 km-long photonic crystal fiber with zero GVD in the near IR suitable for picosecond pulse propagation at the 800 nm band

Summary form only given. A 2 km-long hexagonal photonic crystal fiber with losses at 1550 and 850 nm of 3.2 and 7.1 dB/km, respectively, was successfully fabricated. The zero GVD wavelength was measured to be 810 nm, and picosecond optical pulses at 815 nm were successfully propagated through the fiber.

Integrated 100-Gb/s PDM-QPSK modulator using a hybrid assembly technique with silica-based PLCs and LiNbO 3 phase modulators

We demonstrate a PDM-QPSK modulator operating at 100-Gb/s. Two QPSK modulators and a polarization beam combiner are integrated using a hybrid assembly technique with silica PLCs and LiNbO3 phase modulators.

Ultralong dispersion-shifted erbium-doped fiber amplifier and its application to soliton transmission

Distributed, dispersion-shifted erbium-doped fiber amplifiers with doping concentrations as low as 0.1-0.5 p.p.m. (0.1-0.5*10/sup -4/ wt.%) were fabricated and their grain characteristics studied for the purpose of soliton amplification. A 9.4-km dual-shape-core-type amplifier with a 0.5-p.p.m. concentration had a gain of more than 20 dB at 1.535 mu m and 10 dB at 1.552 mu m with a forward pumping configuration, and it could successfully amplify and transmit a 20-ps soliton pulse train at a 2.5-GHz repetition rate. The soliton transmission characteristics of an 18.2 km long fiber amplifier were studied using backward and forward pumping. It was found that A=1.5 soliton pulses with a pulse width of 20 ps could be amplified over 18.2 km at a repetition rate of 5 GHz, where soliton narrowing to 16 ps was observed. >

Polarization-Insensitive Operation of Lithium Niobate Mach–Zehnder Interferometer With Silica PLC-Based Polarization Diversity Circuit

We demonstrate the polarization-insensitive operation of a Mach-Zehnder interferometer (MZI)-based lithium niobate switch with a silica waveguide polarization beam splitter. The splitter is composed of an MZI with a half wave plate installed in one arm, and exhibits a polarization extinction ratio of more than 15 dB. The switch functions for both polarizations with an extinction ratio of more than 20 dB, a polarization-dependent loss of 0.1 dB and a switching speed of 40 ps.

High-Speed Optical 1

We demonstrate a high-speed optical switch based on a generalized Mach-Zehnder interferometer with a hybrid configuration consisting of a silica-based planar lightwave circuit and lithium niobate phase shifters. The novel switch demonstrated here has one input and four output ports and a switching time of less than 0.1 mus, thanks to the fast response of the electrooptic phase shifters on the LN chip. The insertion loss and extinction ratio of the switch are 4.2 dB and more than 17 dB, respectively

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We demonstrate a tunable optical dispersion compensator consisting of an arrayed-waveguide grating and a liquid crystal on silicon. We obtained a tuning range of ± 800 ps/nm with a bandwidth of 16 GHz.