Nippon Telegraph and Telephone Corporation

Hamamatsu-photonics K.k.

Ntt Advanced Technology Corporation

Tadashi Sakamoto

Takashi Sakamoto

Seiji Toyoda

Makoto Shimizu

Joji Yamaguchi

Yuzo Sasaki

Makoto Yamada

Masahiro Ueno

Shoichi Sudo

Terutoshi Kanamori

Jun-ichi Kani

Yasutake Ohishi

Yuichi Akage

Shinichi Aozasa

Shigeki Aisawa

Yoshiki Nishida

Masahiko Jinno

Meishin Chin

Seiji Norimatsu

Shoko Tatsumi

Atsushi Mori

Koei Yamamoto

Kazuo Fujiura

Hiroji Masuda

Masatoshi Fujimoto

Shogo Yagi

Koji Yoneyama

Eiichi Sugai

Kouji Shikano

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

New fiber lasers, spontaneous emission sources, and optical fiber amplifiers are provided. Their conventional counterparts, which have a fiber doped with thulium (Tm) ions and excited by 0.67 &#x3bc;m or 0.8 &#x3bc;m pumping light, have a problem in that their characteristics are deteriorated with the elapse of time. The new fiber lasers, spontaneous emission sources, and optical fiber amplifiers use 1.2 &#x3bc;m light as pumping light. Alternatively, they use a pumping source for exciting the thulium from the lowest energy levelHtoHexcitation level. As a more preferable configuration, they improve the emission efficiency at 2.3 &#x3bc;m band by disclosing Tm-doped host glass.

Fiber laser, spontaneous emission light source and optical fiber amplifier

In a wavelength division multiplexed optical transmission system wherein the zero dispersion wavelength of the optical fiber transmission pathis in the 1550 nm region, among multiplexed optical signals, the wavelengths of either of at least two optical signals are allocated between 1450 nm and 1530 nm, or between 1570 nm and 1650 nm.

Wavelength division multiplex optical transmission system

An optical fiber amplifier with a high conversion efficiency, which is capable of using the pump light in the wavelength band that can be emitted by the laser diode, is formed by an amplification optical fiber containing thulium at least in a core, to which a signal light is to be entered, and a pump light input unit configured to enter at least one pump light with a wavelength in a range of 1320-1520 nm, or more preferably 1320-1480 nm, into the amplification optical amplifier.

Thulium-doped fiber amplifier using pump light for improving conversion efficiency in a S-band

In a wavelength division multiplexed optical transmission system wherein the zero dispersion wavelength of the optical fiber transmission path is in the 1550 nm region, among multiplexed optical signals, the wavelengths of either of at least two optical signals are allocated between 1450 nm and 1530 nm, or between 1570 mn and 1650 nm.

Wavelength division multiplexing optical transmission system

This invention relates to fluoride glass with a specific composition having wide infrared transmission. A fluoride optical fiber using this fluoride glass can give high efficiency with a low loss. The fluoride optical fiber having a second cladding on the outer periphery of a first cladding can adjust the refractive index of the first cladding suitably.

Fluoride glass fiber

An amplifying optical fiber includes a core containing Tm ions as activation ions and a clad containing at least one of Tb ions and Eu ions. Alternatively, the amplifying optical fiber includes a core composed of more than two layers. Tm is contained in more than one of the more than two layers as activation ions and at least one of Tb ions and Eu ions is contained in more than one of the more than two in which Tm is not contained.

Optical fibers for optical amplifiers

Growing community of inventors

Atsugi, Japan

Tadashi Sakamoto