Nippon Telegraph and Telephone Corporation

Ryo Nakao

Shinji Matsuo

Takaaki Kakitsuka

Tomonari Sato

Suguru Yamaoka

A device includes a first cladding layer, a waveguide laser, an absorption layer, and a second cladding layer. The absorption layer is constituted by an oversaturation absorption body such as graphene. Also, the absorption layer is provided between the active layer and the distributed Bragg reflection portion. The absorption layer is formed below a core forming an optical waveguide between the active layer and a distributed Bragg reflection portion.

Optical device

A semiconductor optical module includes a semiconductor laser element region having an active layer, a first cladding layer which is formed such that the active layer is embedded therein, a second cladding layer which is formed underneath the active layer and the first cladding layer, and a heater unit which produces a temperature change in a waveguide; an optical waveguide element region including a spot-size converter which converts a spot size of incident laser light, and an optical waveguide core layer which is formed such that the spot-size converter is embedded therein, the first cladding layer contains InP, the second cladding layer is made of a material lower in refractive index and higher in thermal conductivity than the first cladding layer, and a third cladding layer which is made of a material lower in refractive index and lower in thermal conductivity than the second cladding layer is formed underneath the spot-size converter and the heater unit.

Semiconductor optical module

A second semiconductor layer is oxidized through a groove and a fourth semiconductor layer is oxidized, a first oxide layer is formed, and a second oxide layer is formed. By oxidizing the entire second semiconductor layer and the fourth semiconductor layer, the first oxide layer and the second oxide layer in an amorphous state are formed.

Method for forming semiconductor layers

In an embodiment, a first recess and a second recess, designed to reach a first semiconductor layer, are formed in the portions of a first threading dislocation and a second threading dislocation having reached the surface. Further, the first semiconductor layer is oxidized through the first recess and the second recess to form an insulating film configured to cover the lower surface of a second semiconductor layer.

Method for forming semiconductor layer

A semiconductor optical device that achieves both of heat dissipation and light confinement and permits efficient current injection or application of an electric field is implemented. The semiconductor optical device includes: a core layer including an active region () made of a compound semiconductor; two cladding layers () injecting current into the core layer; and a third cladding layer () made of a material having a larger thermal conductivity, a smaller refractive index, and a larger band gap than a material for any of the core layer and the two cladding layers.

Growing community of inventors

Atsugi, Japan

Ryo Nakao