Nippon Telegraph and Telephone Corporation

Ntt Electronics Corporation

Hiroyasu Mawatari

Hiroyuki Suzuki

Hiroshi Miyazawa

Osamu Tadanaga

Yoshiki Nishida

Masaki Asobe

Tsutomu Yanagawa

Junji Yumoto

Eishi Kubota

Kaoru Yoshino

Hirohisa Kanbara

Nobuhiro Kikuchi

Yoshihiro Ogiso

Katsuaki Magari

The present invention provides a highly reliable, high-speed, and low-loss semiconductor optical modulation element that protects a pin junction structure in a modulation region against reverse voltage ESD by configuring an additional capacity having a thyristor structure between a plurality of feeding pad electrodes. An n-type contact layer, an n-type cladding layer, a non-doped core/cladding layer, a p-type cladding layer, and a p-type contact layer are sequentially laminated on the substrate surface. A Mach-Zehnder interferometric waveguide and a plurality of feeding pad installation sections are formed by dry etching. The n-type contact layer and the n-type cladding layer are removed except for a modulation region of the Mach-Zehnder interferometric waveguide and a feeding region in which the feeding pad installation sections are formed so that the modulation region and the semiconductor of the lower part of the feeding region are electrically isolated from each other. The feeding pads are formed on the common n-type contact layer and n-type cladding layer. A thyristor structure of a pinip junction is formed between the feeding pads.

Semiconductor optical modulation element

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

Hiroyasu Mawatari