Mitsubishi Rayon Company, Limited

Takeshi Kitayama

Kazuki Nakamura

Takara Yamamoto

Hiroe Kubo

Katsuhiko Shimada

Jun Okumura

Motomu Oh-Kita

Shigeaki Sasaki

Yoshihiro Uozu

Hirotoshi Mizota

Yasukazu Yoshida

Tomonari Murakami

Koji Ishizaka

Tatsuyuki Takayanagi

Jun-ichiro Atarashi

Masaharu Yanai

Yoshihiro Tsukamoto

Hideki Kihara

Yoshimi Kamimura

Provided is a multi-core optical fiber which is capable of achieving the same level of light receiving capacity as that of a single-core plastic optical fiber, while being reduced in bending loss. A multi-core optical fiber according to the present invention has a plurality of cores and sea portions that are formed around each core. This multi-core optical fiber satisfies at least condition (1) or condition (2) below: (Condition 1): The occupancy rate of the total cross-sectional area of cores is 80&#x2dc;95% of the outer region in the cross section of a multicore optical fiber. (Condition 2): The occupancy rate of the total cross-sectional area of cores is 82&#x2dc;93% of the cross section of a multicore optical fiber.

Multicore optical fiber and multicore optical fiber cable

This invention provides a process for manufacturing a methyl methacrylate polymer comprising the steps of feeding a monomer containing at least 80 wt % of methyl methacrylate and a radical polymerization initiator represented formula (III) to a reactor; polymerizing the material at a polymerization temperature of 110 to 160&#xb0; C. under the conditions satisfying particular equations between an initiator concentration and a polymerization temperature; feeding a reaction mixture taken out from the reactor to a devolatilization step (feeding step); and separating and removing volatiles from the reaction mixture (devolatilization step). A methyl methacrylate polymer having adequately good optical properties and a plastic optical fiber having improved transmission performance can be prepared according to this invention 

Plastic optical fiber, optical fiber cable, optical fiber cable with plug, method for producing methyl methacrylate based polymer and method for producing plastic optical fiber

Disclosed are an optical fiber cable comprising an optical fiber and at least one covering layer formed on the outer periphery of the optical fiber, at least one layer of the covering layer being made of a material comprising a resin component containing a polyamide polymer, wherein a flexural modulus E upon displacement of 1 mm is within a range from 2 to 15 (N/mm) and the optical fiber cable passes a flame resistance test in accordance with DIN 72551-5, and an optical fiber cable with a plug using the optical fiber. Therefore, they have excellent flame resistance and good handling properties.

Optical fiber cable and optical fiber cable with plug

The optical fiber cord of the present invention is characterized in having a primary covering layer formed from a polyamide resin that incorporates at least one of an organic acid or an organic acid anhydride on the outer periphery of the optical fiber. In addition, the optical fiber cord with a plug of the present invention has a plug on at least one end of the optical fiber cord of the present invention having a secondary covering layer on the outer periphery, wherein at the end part of the optical fiber cord that has the plug, the primary covering layer is exposed, and the plug is fastened to the exposed primary covering layer. By using the structure described above, an optical fiber cord and an optical fiber cord with a plug that has superior humidity resistance and heat resistance, and in addition can be laid easily in narrow sites because of superior flexibility and is inexpensive. The optical fiber cord and the optical fiber cord with a plug of the present invention can be favorably employed in uses that require thermal resistance such as installation on a vehicle or in factory automation (FA).

Optical fiber cord and optical fiber cord with a plug

This invention provides a process for manufacturing a methyl methacrylate polymer comprising the steps of feeding a monomer containing at least 80 wt % of methyl methacrylate and a radical polymerization initiator represented formula (III) to a reactor; polymerizing the material at a polymerization temperature of 110 to 160&deg; C. under the conditions satisfying particular equations between an initiator concentration and a polymerization temperature; feeding a reaction mixture taken out from the reactor to a devolatilization step (feeding step); and separating and removing volatiles from the reaction mixture (devolatilization step). A methyl methacrylate polymer having adequately good optical properties and a plastic optical fiber having improved transmission performance can be prepared according to this invention.

The present invention discloses an optical fiber cable of diameter D (mm) in which an adhesive layer having a thickness of 0.5 to 200 &mgr;m, a primary coating layer and a secondary coating layer are sequentially formed around the outside of an optical fiber in which the outermost layer is composed of vinylidene fluoride polymer; wherein, in the case the diameter of the optical fiber is represented with Da (mm), the thickness of the adhesive layer is represented with d (mm), and Da&plus;2d is represented with D , then D /D &equals;1.2 to 3.5, and an optical fiber cable with plug that uses this optical fiber. Thus, the resulting optical fiber cable has superior flame resistance, is resistant to peeling of the optical fiber and coating layers, and is resistant to the occurrence of pistoning phenomenon. The optical fiber may also be composed of a core, a sheath formed around the core, and a protective layer formed around the sheath.

An optical fiber cable having a diameter of D (mm) and comprising an adhesion layer 0.5 to 200 &mgr; in thickness, a primary coating layer, and a secondary coating layer, all sequentially formed on the outer circumference of an optical fiber constituted on the outermost layer thereof by vinylidene fluoride polymer, wherein D /D &equals;1.2 to 3.5 (the diameter of the optical fiber is Da (mm), the thickness of the adhesion layer d (mm), and Da&plus;2d&equals;D ); and an optical fiber cable with a plug using this optical fiber. Accordingly, these optical fiber cables are excellent in flame resistance, difficult in separating an optical fiber thereof from coating layers, and not likely to cause a pistoning phenomenon. An optical fiber may consist of a core, a sheath formed on the periphery of the core and a protection layer formed on the periphery of the sheath.

Growing community of inventors

Toyama, Japan

Takeshi Kitayama