Masahiro Ogusu

A thermally stable Fabry-Perot tunable filter for 1 AA-spaced high-density WDM systems

A new tunable filter using two nonidentical Fabry-Perot etalons arranged on a single rotation stage has been demonstrated. The 3-dB passband, tuning range, and insertion loss were 0.2 AA, 1.2 nm, and 1.5 to 3 dB, respectively. The thermally induced wavelength deviation of the output was within 0.02 AA in the range of 0 to 50 degrees C. The sharp wavelength characteristics and the good temperature stability promised to operate FSK-DD stably where the wavelength spacing of FSK signals was 1 AA.<<ETX>>

Ultra-Dense WDM with over 100% Spectral Efficiency Using Co-polarized 40-Gb/s Inverse-RZ Signals

An inverse-RZ modulation scheme for dense WDM systems is proposed. Inverse-RZ signals have tolerances to chromatic dispersion and optical bandwidth limitation. The strongly pre-filtered inverse-RZ signals can be adapted to ultra-dense WDM systems, in which the spectral efficiencies are over 1.0b/s/Hz. We have confirmed the error-free transmission of pre-filtered and co-polarized 40-Gb/s inverse-RZ signals where the channel intervals were 37.5 GHz.

Fast and precise wavelength switching of an SG-DBR laser for 1.07-b/s/Hz DVMM systems

Fast (<100-/spl mu/s) and precise (/spl plusmn/2-GHz) wavelength switching of an SG-DBR laser with fast feedback frequency control is confirmed by using 1.07-bit/s/Hz DWDM of 40-Gb/s pre-filtered inverse-RZ signals.

Wavelength Lock System Using a Quartz Etalon Supported at the Middle Point

This paper presents a wavelength lock system using a Z-cut quartz etalon supported at the middle point. The Z-cut quartz etalon possesses the cavity length modulation and the low temperature coefficient. We propose a Z-cut quartz etalon supported at the middle point in order to improve the modulation index and response time. The mechanism of the center supported Z-cut quartz etalon is described. We also show that the etalon possesses a high modulation index, a high Q factor, and a rapid response time in experimental results. A self-tuning dither oscillator realized by using quartz etalon is also described.