Nippon Telegraph and Telephone Corporation

Hirohisa Kanbara

Hiroyuki Suzuki

Takashi Kurihara

Hiroshi Miyazawa

Osamu Tadanaga

Yoshiki Nishida

Masaki Asobe

Eishi Kubota

Kaoru Yoshino

Shiro Matsumoto

Hiroyasu Mawatari

Tsutomu Yanagawa

Junji Yumoto

Kenichi Kubodera

Toshikuni Kaino

Toshikuni Kainou

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.

A nonlinear optical device having an optical medium and an optical element including a polarizer, an optical resonator and a reflector is provided. The optical medium includes an organic nonlinear optical material represented by a formula: ##STR1## wherein each of R.sub.1 and R.sub.2 is an alkyl group having 2 to 6 carbon atoms or a hydroxyalkyl group having 2 to 6 carbon atoms, R.sub.1 and R.sub.2 being same or different groups; or R.sub.1 is an ethyl group and R.sub.2 is an acryloyloxyethyl group (CH.sub.2 .dbd.CH--COO--CH.sub.2 CH.sub.2 --) or a methacryloyloxyethyl group (CH.sub.2 .dbd.C(CH.sub.3)--COO--CH.sub.2 CH.sub.2 --); and each of X.sub.1, X.sub.2, X.sub.3, and X.sub.4 is individually a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, an alkoxy group, an alkyl ester group, or an alkylamide group, where X.sub.1, X.sub.2, X.sub.3 and X.sub.4 may be the same or different groups.

Organic nonlinear optical material and nonlinear optical device

An organic nonlinear optical device having a nitrostyrene compound represented by a formula: ##STR1## wherein R.sub.1 is an ethyl group R.sub.2 is a group selected from the group consisting of an acryloyloxyethyl group (CH.sub.2 .dbd.CH--COO--CH.sub.2 CH.sub.2 --) and a methacryloyloxyethyl group (CH.sub.2 .dbd.C(CH.sub.3)--COO--CH.sub.2 CH.sub.2 --); and X.sub.1, X.sub.2, X.sub.3, and X.sub.4 are the same or different and each is selected from the group consisting of a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, an alkoxy group, an alkyl ester group, and an alkylamide group, is provided.

Growing community of inventors

Isehara, Japan

Hirohisa Kanbara