Nippon Telegraph and Telephone Corporation

Dai Nippon Printing Co., Ltd.

Other

Dai Nippon Printing Co., Ltd. and Nippon Telegraph and Telephone Corporation

Tetsuro Komukai

Masaaki Kurihara

Masataka Nakazawa

Tetsuro Inui

Toshikazu Segawa

Shigekazu Fujimoto

Kohichi Robert Tamura

Shigekaza Fujimoto

The invention relates to a process for the fabrication of an optical fiber-processing phase mask that is reduced in terms of pitch variations on the mask and stitching errors, and provides a process for the fabrication of a chirped type optical fiber-processing phase mask wherein a grating form of grooves provided in one surface of a quartz substrate is configured as an optical fiber-processing grating pattern. At an exposure step, writing data obtained by arranging and compiling a plurality of data for a repetitive groove-and-strip pattern while the pitch of repetition is modulated are used and an electron beam resist is provided on a phase mask blank, so that writing is carried out all over the writing area on said phase mask blank continuously in a vertical direction to said grating form of grooves.

Process for the fabrication of a phase mask for optical fiber processing, optical fiber-processing phase mask, optical fiber with a Bragg grating, and dispersion compensating device using the optical fiber

The present invention relates to a precision phase mask for forming diffraction grating in optical fiber and optical waveguide, to provide them with nonlinear chirped grating for dispersion compensation use and having low fluctuation or crosstalk in the group delay characteristics. The diffraction grating is formed by means of interference fringe between diffracted lights of different orders, in which the cycle of the diffraction gratingincreases nonlinearly, wherein plurality of diffraction gratings G, G, G. . . having different cycles are assembled on a plane in increasing order of the cycle with the directions of the diffraction gratings directed to the same direction, and assembled in such a manner that, where the cycle of grating changes nonlinearly and discontinuously, the regions having larger rate of change of the cycle contain proportionally more discontinuous phases per unit length.

Phase mask for forming diffraction grating, and optical fiber and optical waveguide having diffraction grating duplicated using the phase mask

The present invention relates to a method of producing an optical fiber-processing phase mask having minimized connection errors that may degrade the spectral line shape and group delay characteristics of an optical fiber diffraction grating fabricated by using the phase mask. The present invention provides a method of producing an optical fiber-processing phase mask having a repeating pattern of grating-shaped grooves and strips provided on one surface of a transparent substrate, so that diffracted light produced by the repeating pattern is applied to an optical fiber to fabricate a diffraction grating in the optical fiber by interference fringes of diffracted light of different orders. In making a mask having a plurality of juxtaposed patterns (P to P ) having a linearly or nonlinearly increasing or decreasing pitch and a uniform groove-strip width ratio, multiple exposure is carried out to minimize difference between the pitch at the joint between patterns having different pitch data and the pitch in each individual pattern.

Method of making phase mask for machining optical fiber and optical fiber having bragg diffraction grating produced using the phase mask for machining optical fiber

An arrayed-waveguide grating (AWG) is provided in a tunable mode-locked laser resonator where when a clock signal corresponding to a predetermined wavelength is input, the arrayed-waveguide grating (AWG) generates an output signal having an oscillation wavelength which has an arbitrary wavelength interval independent of the wavelength of said clock signal and a different propagation delay for each wavelength. Furthermore, a transmitter and a wavelength converter is provided that uses a tunable mode-locked laser where the frequency of the clock signal determines the wavelength and where a transmitted data signal at a fixed data rate is generated by setting the clock signal frequency sufficiently higher than the data rate. Furthermore, a wavelength converter and wavelength router is provided that uses said tunable mode-locked laser and in which the output wavelength is determined by extracting said clock signal from the input data signal. Furthermore, a transmission system is provided that uses said transmitter and/or said wavelength converter, and a receiver that recovers the envelope of said transmitted data signal.

Wavelength-tunable mode-locked laser, wavelength converter and transmission system

The invention relates to a method of fabricating an optical fiber-processing phase mask in which a stitching error ascribable to a deterioration in the wavelength selectivity of the optical fiber diffraction grating to be fabricated is reduced. At an exposure step, a writing stage with a phase mask blank placed thereon is continuously fed in one direction while portions of the phase mask blank corresponding to grooves or strips in a direction perpendicular to the direction of feeding are sequentially scanned with writing beams , whereby the entire area of the phase mask blank to be written is continuously written.

Growing community of inventors

Tokyo, Japan

Tetsuro Komukai