Nippon Telegraph and Telephone Corporation

Ntt Electronics Corporation

Tsutomu Yanagawa

Osamu Tadanaga

Yoshiki Nishida

Masaki Asobe

Hiroyuki Suzuki

Hiroshi Miyazawa

Hiroyasu Mawatari

Junji Yumoto

Eishi Kubota

Kaoru Yoshino

Hirohisa Kanbara

Katsuaki Magari

Takeshi Umeki

A wavelength converter which performs simultaneously wavelength conversion for a plurality of input light wavelengths that are unequally intervals, is provided. The nonlinear material of the wavelength converter has a modulation structure which has modulation of a nonlinear optical constant at a period &#x39b;in a propagating direction of light, a phase being continuously changed each period &#x39b;and a continuous phase modulation for a different period &#x39b;being added to the modulation structure. The nonlinear material has a modulation structure obtained by changing a modulation curve for the phase modulation, wherein a phase mismatch &#x394;&#x3b2; is represented by &#x394;&#x3b2;=2&#x3c0;(n/&#x3bb;&#x2212;n/&#x3bb;&#x2212;n/&#x3bb;), and at least three peaks at unequally intervals within a plurality of peaks for conversion efficiency represented by 2&#x3c0;/&#x39b;+2&#x3c0;i/&#x39b;(i=m, m+1, . . . , n: where m and n are positive or negative integers) have highest conversion efficiency.

Wavelength converter and wavelength conversion apparatus

A light source apparatus with modulation function has a wavelength conversion module () composed of a nonlinear optical material with a structure having a nonlinear constant modulated periodically. It outputs a difference frequency or sum frequency produced by multiplexing pumping light from semiconductor laser light sources () and () with different wavelengths through a WDM coupler () and by launching the multiplexed light into the optical waveguide. The semiconductor laser light source () includes a diffraction grating. The semiconductor laser light source () includes a section for modulating output light emitted from its semiconductor laser, and is connected to an external FBG () which has a reflection band narrower than a resonance wavelength spacing determined by the device length of the semiconductor laser. The FBG () is supplied with the modulated output.

Light source apparatus with modulation function and its driving method

A laser light source is disclosed consisting of first and second lasers that respectively generate laser beams of wavelengths &#x3bb;and &#x3bb;. Wavelength &#x3bb;is in the range of 0.9-1.0 &#x3bc;m. A nonlinear optical crystal uses the laser beams of wavelengths &#x3bb;and &#x3bb;as inputs, and outputs a coherent beam having a wavelength &#x3bb;of a difference frequency that satisfies a relationship of 1/&#x3bb;&#x2212;1/&#x3bb;=1/&#x3bb;. The nonlinear optical crystal has a periodically poled structure of a single period. The wavelength &#x3bb;of the difference frequency varies between 3.1 &#x3bc;m and 2.0 &#x3bc;m when the wavelength &#x3bb;varies between 1.3 &#x3bc;m and 1.8 &#x3bc;m.

Laser light source

The invention provides a compact laser light source whose wavelength can be designed freely in a wavelength band in which the semiconductor laser has not been put to practical use by combining an efficient nonlinear optical crystal and high-power semiconductor lasers for optical communication. In one embodiment, the laser light source includes: a first laser for generating a laser beam of a wavelength &#x3bb;; a second laser for generating a laser beam of a wavelength &#x3bb;; and a nonlinear optical crystal that allows the laser beam of wavelength &#x3bb;and the laser beam of wavelength &#x3bb;as inputs and outputs a coherent beam having a wavelength &#x3bb;of a sum frequency that satisfies a relationship of 1/&#x3bb;+1/&#x3bb;=1/&#x3bb;. The wavelength &#x3bb;of the sum frequency is 589.3&#xb1;2 nm that is equivalent to the sodium D line.

Growing community of inventors

Isehara, Japan

Tsutomu Yanagawa