Nippon Telegraph and Telephone Corporation

Hamamatsu-Photonics K.k.

Ando Electric Company

Ntt Advanced Technology Corporation

Nippon Telegraph and Telephone Communications

Seiji Toyoda

Takashi Kurihara

Tadayuki Imai

Kazuo Fujiura

Masahiro Sasaura

Koji Enbutsu

Shogo Yagi

Makoto Shimokozono

Saburo Imamura

Shoichi Hayashida

Takashi Sakamoto

Makoto Abe

Satoru Tomaru

Tohru Maruno

Akiyuki Tate

Eishi Kubota

Touru Matsuura

Hiroshi Fushimi

Masahiro Ueno

Tadashi Sakamoto

Joji Yamaguchi

Yuzo Sasaki

Yuichi Akage

Meishin Chin

Jun Miyazu

Tohru Matsuura

Shoko Tatsumi

Mitsuru Shinagawa

Toshio Watanabe

Yasuyuki Inoue

Tadashi Minotani

Koei Yamamoto

Toshiaki Tamamura

Masatoshi Fujimoto

Naoki Ooba

Kazuto Noguchi

Yuichi Okabe

Kazunori Naganuma

Tetsuyoshi Ishii

Kazutoshi Kato

Shigeo Ishibashi

Nobutarou Shibata

Koji Yoneyama

Emiko Fujiwara

Eiichi Sugai

Aiichirou Sasaki

Yukihiko Ushiyama

Mahiro Yamada

A swept light source of the present invention keeps a coherence length of an output beam long over an entire sweep wavelength range. A gain of a gain medium is changed with time in response to a wavelength sweep and the coherence length is kept maximum. The gain of the gain medium is kept close to a lasing threshold and an unsaturated gain range of the gain medium is narrowed over the entire sweep wavelength range. An SOA current waveform data acquiring method of driving while keeping the coherence length long, a novel coherence length measuring method, and an optical deflector suitable for the swept light source are also disclosed.

Swept light source and drive data generation method and optical deflector for swept light source

Provided is a swept light source including one end surface coupled to a wavelength filter constituted of a diffraction grating and an end mirror via a light deflector and another end surface including a gain medium facing an output coupling mirror and which configures a laser cavity between the end mirror and the output coupling mirror, wherein a drive voltage having an AC voltage on which a DC bias voltage is superimposed is output from a control voltage source of the light deflector to an electrode pair of an electro-optic crystal, light is radiated from a light emitter to the electro-optic crystal, and incident light from the gain medium incident along an optical axis perpendicular to a direction of an electric field formed by the control voltage is deflected in a direction parallel to the electric field, so that wavelength sweeping is performed.

Swept light source and method for controlling the same

A wavelength swept light source includes a sawtooth waveform as a main waveform and an exponential component of the sawtooth waveform to the controlled voltage of the electro-optic deflector. The controlled voltage is controlled so that, as an oscillation wavelength to be swept is swept towards a longer wavelength side, a change rate of the oscillation wavelength is increased.

Wavelength swept light source

A variable focusing lens is provided that can change the focal length at a high speed. The variable focusing lens includes: a single crystal electrooptic material having inversion symmetry; a first anode formed on a first surface of the electrooptic material; a second cathode provided to have an interval to the first anode; and a first cathode and a second anode that are formed on a second surface opposed to the first surface and that are formed at positions opposed to the first anode and the second cathode. An optical axis is set so that, when light enters through a third face orthogonal to the first surface, light exists through a fourth surface opposed to the third face. A voltage applied between the first and the second pair of electrodes is changed to thereby change the focal point of light emitted from the fourth surface of the electrooptic material.

Variable focusing lens and microscope

The present invention relates to an electric field sensor including: a light source (); an electro optic crystal () which is applied with an electric field based on a signal under test, in which a birefringent index changes according to the electric field, and which changes a polarization state of light incident from the light source according to the birefringent index and emits the light; and a detector () that detects an electric signal according to the change of the polarization state of the light emitted from the electro optic crystal (). Further, the electric field sensor includes: a signal electrode () for applying the electric field based on the signal under test to the electro optic crystal (); a counter electrode () that forms a pair with the signal electrode (); and an auxiliary electrode () that is electrically connected to the counter electrode (), and that forms a capacitance with ground.

Electric field sensor

The present invention provides an optical switch, an optical modulator, and a wavelength variable filter each of which has a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch according to the present invention includes a 3-dB coupler () placed on an input, a 3-dB coupler () placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section () that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaNbO(0&#x3c;x&#x3c;1) and KLiTaNbO(0&#x3c;x&#x3c;1, 0&#x3c;y&#x3c;1), or KTaNbOor KLiTaNbO.

Optical switch, optical modulator and wavelength variable filter

A photosensitive composition for optical waveguides comprising of an organic oligomer, a polymerization initiator and a crosslinking agent, the organic oligomer being a silicone oligomer represented by the following formula (1), wherein X denotes hydrogen, deuterium, halogen, an alkyl group or an alkoxy group; m is an integer from 1 to 5; x and y represent the proportion of respective units, and neither x nor y is 0; and Rdenotes a methyl, ethyl, or isopropyl group; a production method thereof, and a polymer optical waveguide pattern formation method using the same 

Photosensitive composition for manufacturing optical waveguide, production method thereof and polymer optical waveguide pattern formation method using the same

An optical switch, an optical modulator, and a wavelength variable filter each have a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch includes a 3-dB coupler placed on an output, a 3-dB coupler placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaNbO(0&#x3c;x&#x3c;1) and KLiTaNbO(0&#x3c;x&#x3c;1, 0&#x3c;y&#x3c;1), or KTaNbOor KLiTaNbO.

The invention provides an optical waveguide material whose refractive index can be tailored without changing the ratio of Ta and Nb. An optical waveguide of this invention comprising an under-clad layerand a corethat is formed on the under-clad layerand has a higher refractive index than that of the under-clad layeris shown. For example, KTN (KTaNbO) is used as the core, and a material that is obtained by substituting at least one element selected from the group consisting of Zr, Hf, and Sn for a portion of one element of the constituent elements of KTN and has the same perovskite type crystal structure as KTN is used as the clad. The refractive index of KTN can be reduced considerably, and this controllability widens the degree of freedom in the design of optical waveguide devices.

Optical waveguide material and optical waveguide

An optical waveguide capable of having various characteristics and a method of manufacture thereof as well as a method of manufacturing a crystal film are provided. An optical functional material KTaNbOis used as an optical waveguide. The input optical signal is transmitted to the KTaNbOfilm. The KTaNbOfilm undergoes changes in optical property when an external voltage signal is applied to the electrode. Therefore, as it passes through the KTaNbOfilm, the input optical signal is modulated by the characteristic change. The modulated optical signal is taken out as an output optical signal.

Optical waveguide and method of manufacture

Growing community of inventors

Atsugi, Japan

Seiji Toyoda