Hitachi Metals, Ltd.

Masahiro Ao

Shinji Furuichi

Hirohide Yamada

Masaru Suzuki

Shigetoshi Morita

Yoshiaki Takada

Akira Taguchi

Shunichi Taka

Ryo Goto

Fumio Nitanda

Takeshi Fukuyama

An optical power monitor capable of being reduced in size even when designed as a multi-channel monitor, and having a reduced light transmission loss is disclosed. The optical power monitor has two optical fibers provided on the light transmission upstream and downstream sides and having cores, the end surfaces which are opposed to each other with the core optical axes offset from each other, and which are fusion-spliced to each other in a fusion splicing portion, a light reflection surface which faces a portion of the upstream-side optical fiber core end surface offset to protrude from the downstream-side optical fiber core end surface in the fusion splicing portion, and which is provided in the downstream-side optical fiber cladding layer, and a photo-diode positioned opposite from the light reflection surface with respect to the downstream-side optical fiber core. Third-order or fourth-order lights strengthening each other in lights leaked into the downstream-side optical fiber cladding layer from the upstream-side optical fiber core end surface are reflected by the reflection surface provided in the cladding layer and detected with the photo-diode.

Optical power monitor

The invention provides a variable optical attenuator capable of adjusting the attenuation of an optical signal to obtain the optical signal having a controlled intensity. The variable optical attenuator includes a circular loop formed by winding an optical fiber by at least one turn. The circular loop of the optical fiber is mechanically transformed into an oval loop to change the curvature radius at the deflected part of the optical fiber so that the attenuation of the output light is adjusted.

Variable optical attenuator

An optical fiber array with lenses connected with a plurality of optical fibers is disclosed, enabling to be manufactured to meet the optical fiber end intervals to the terminal intervals of an optical device to be connected and having an improved efficiency in connection operation. The optical fiber array comprises a base plate having a first end surface and a second end surface opposite to the first end surface, a plurality of optical fibers having a tip surface inserted and secured in each of the holes opened on the base plate, and a plurality of collimator lenses installed on the second end surface facing the tip surfaces of the optical fiber. Each hole has a tapered inside wall having a diameter gradually decreasing from an opening on the first end surface of the base plate toward the second end surface and a parallel inside wall continuing from the tapered inside wall end. In the hole, a refraction index matching agent is preferably filled in between the tip surface of the optical fiber and the collimator lens. The optical fiber array is designed so as to match the optical axis pitches of the optical fibers and collimator lenses to the terminal pitches of the optical device to be connected.

Optical fiber array with lenses

Two floating rails are provided on a slider of a floating magnetic head. Rear portions, in the advancing direction of a floating magnetic head with respect to a magnetic recording medium, of the respective floating rails are cut out. That is, the floating rails exist only in front of the cut-out portions. An auxiliary rail is formed in the rear of one of the floating rails. The auxiliary rail is narrower than the floating rail, wider than the track width of an electromagnetic conversion element, and approximately as high as the floating rail. The electromagnetic conversion element is provided at a rear portion of the auxiliary rail.

Floating magnetic head

A floating type magnetic head is made of a polycrystalline material. A surface to be opposed to a magnetic recording medium is undulated with lands and grooves having a height difference of 50 to 200 .ANG. on an average and a repetition pitch of 5 to 20 microns on an average. The portions, in which the heights of the lands and the grooves abruptly change, extend along the boundaries of the polycrystals. The head surface opposed to the magnetic recording medium is sputter-etched to have the predetermined surface roughness.

Method of fabricating a magnetic head by sputter etching

A floating type magnetic head is made of a polycrystalline material. A surface to be opposed to a magnetic recording medium is undulated with lands and grooves having a height different of 50 to 200 .ANG. on an average and a repetition pitch of 5 to 20 microns on an average. The portions, in which the heights of the lands and the grooves abruptly change, extend along the boundaries of the polycrystals. The head surface opposed to the magnetic recording medium is sputter-etched to have the predetermined surface roughness.

Growing community of inventors

Tochigi, Japan

Masahiro Ao