Fujikura Limited

Shimon Ishikawa

Ken Sakuma

Hideyuki Hosoya

Akira Wada

Hirokuni Ogawa

Tomoko Shikata

Takeshi Fukuda

Tomoko Fujii

The present invention relates a method for manufacturing an optical coupler/splitter. A Y-shaped waveguide core is formed by focusing a laser beam into a cladding layer that is formed from a glass material. At least one portion of this Y-shaped waveguide core other than the input port and the output ports is treated as a refractive index adjustment area. After the portions of the Y-shaped waveguide core other than the refractive index adjustment area have been formed by focusing a laser beam, signal light is inputted into the input port of the Y-shaped waveguide core and the signal light outputted from the output ports of the Y-shaped waveguide core are monitored. The refractive index of the refractive index adjustment area is determined based on the result of the monitoring and is adjusted by focusing a laser beam repeatedly.

Manufacturing method for optical coupler/splitter and method for adjusting optical characteristics of planar lightwave circuit device

When an optical waveguide is formed by focused femtosecond laser pulses in a pure silica glass to induce a refractive index increase region, a pulse width of femtosecond laser pulses are changed, a peak power of femtosecond laser pulses at the focal point is changed, or both the pulse width and the peak power are changed simultaneously. Under conditions where a pulse width of the femtosecond laser pulses is in a range of 210 to 420 fs and a peak power at the focal point is not greater than 8.7&#xd7;10W/cm, an optical waveguide having a mode field of 10 to 14 &#x3bc;m such that an aspect ratio is 1 (one) can be obtained. By doing this, it is possible to control a mode field diameter of an optical waveguide and an aspect ratio of the mode field diameter.

Optical waveguide in the interior of silica glass and method of forming optical waveguide

Growing community of inventors

Sakura, Japan

Shimon Ishikawa