The Furukawa Electric Co., Ltd.

Matsushita Electric Industrial Co., Ltd.

Kouji Mochizuki

Yasuo Nakajima

Hiroki Tanaka

Yoshihiro Arashitani

Mitsunori Okada

Shiro Sakiyama

Minoru Saito

Minoru Kasahara

Takako Uchida

Tetsuo Sato

The present invention provides an optical fiber in which transmission loss is not easily increased when the optical fiber is dipped in water and then dried and also which has a solvent resistant property and a micro-bend resistant property. An optical fiber according to one embodiment of the present invention is an optical fiber in which at least two layers of coating resin coat the circumference of a glass optical fiber. When a Yang's modulus of the first coating layer of the coating resin is defined by PY (MPa) and an elution rate of the coating resin after dipping in 60&#xb0; C. hot water for 168 hours is defined by E (mass&#xb7;%), a formula of 1.8&#x2266;E&#x2266;8.61&#xd7;PY+1.40 is satisfied.

Optical fiber

An optical fiber, which is less likely to increase its transmission loss even when it is exposed to a high-humidity environment or immersed in water, is provided. The optical fiber comprises a glass fiber and at least two coating layers (a soft layer and a hard layer) coated at the circumference of the glass fiber, wherein the limit-adhesion strength between the glass fiber and the coating layer under a hot and humid environment is 0.5N/10 mm or more. Preferably, the glass-transition temperature of the hard layer is less than 90&#xb0; C.

Optical fibers

The present invention provides a colored coated optical fiber which hardly has an increase in transmission loss even when immersed in water. A colored coated optical fiber according to one embodiment of the present invention includes a glass optical fiber, a primary coating layer covering the glass optical fiber, a secondary coating layer covering the primary coating layer, and a colored layer covering the secondary coating layer. A ratio of a thermal expansion coefficient of a laminate including the secondary coating layer and the colored layer covering the secondary coating layer to that of the secondary coating layer is 0.98 or more and 1.03 or less. A ratio of a glass transition temperature based on a dynamic viscoelasticity within a temperature range from &#x2212;100&#xb0; C. to 150&#xb0; C. of the laminate to that of the secondary coating layer is 0.96 or more and 1.03 or less.

Colored coated optical fiber

The present invention provides an optical fiber in which the transmission loss increase is suppressed even under a high-humidity condition or under a water-immersed condition. A colored optical fiber () according to an embodiment of the present invention is a colored optical fiber () formed by applying a colored layer to an optical fiber () including a glass optical fiber coated with at least a double-layered coating layer of a soft layer and a hard layer, and the ratio of thermal expansion coefficient between the coating layer after the colored layer of the colored optical fiber () is applied and the coating layer of the optical fiber () before the colored layer is applied is 0.87 or more. Furthermore, an optical fiber ribbon () according to another embodiment of the present invention is an optical fiber () formed by arranging a plurality of the colored optical fiber () in the form of a plane and coating them all together with a ribbon resin and the ratio of thermal expansion coefficient between the coating layer after the colored layer of the colored optical fiber () is applied and the coating layer of the optical fiber before the colored layer is applied is 0.90 or more.

A coated optical fiber of the present invention comprises a glass fiber coated by at least two coating layers (a soft layer and a hard layer), wherein the glass surface of the glass fiber, where the at least two coating layers of the optical fiber are removed, has a peak intensity ratio of 0.6 or more in CHO+ (m/z 59) or CHO+ (m/z 73) with respect to Si+ (m/z 28) peak in cation analysis of TOF-SIMS. The optical fiber suppresses increase in its transmission loss even when it is exposed to a high-humidity environment or immersed in water.

Coated optical fibers

The present invention provides an optical fiber in which composites constructing its coating are not complicated, so, there is also little constraint in view of production, and, moreover, delamination between a glass optical fiber and a primary layer, and a bubble in the primary layer hardly arise. The optical fiber of the present invention is an optical fiber which has a glass optical fiber which has a core, which passes an optical signal, in a center portion, and a claddingsurrounding this, a primary protective layermade to coat the glass optical fiber, a secondary protective layerapplied on this primary protective layer, and a third protective layerapplied to an outer periphery of this secondary protective layer, wherein glass transition temperature of the primary protective layeris made to be higher than &#x2212;20&#xb0; C. and 10&#xb0; C. or lower, glass transition temperature of the secondary protective layeris made to be &#x2212;10&#xb0; C. or less, and the glass transition temperature of the primary protective layeris set higher than that of the secondary protective layer

The present invention relates to an optical fiber accommodated in an optical fiber cable, and more particularly, to an optical fiber which optimizes optical fiber coating resin and color resin and restrains an increase in transmission loss of the optical fiber due to an operating environment and aged deterioration and provides an optical fiber and optical fiber ribbon without any increase of transmission loss irrespective of the operating environment and aged deterioration, and especially when exposed to water or high humidity. The optical fiber is an optical fiber coated with at least two layers of coating resin, wherein the outermost coated coating resin is a colored layer made of color resin and when the optical fiber is immersed in water which is heated to 60&#xb0; C. for 168 hours, an extraction rate of the coating resin of the optical fiber is set to 1.5 mass percent or below.

Optical fiber and optical fiber ribbon

An optical fiber which reduces transmission loss increase even in a high humidity environment or under water is provided. To solve the above issue, an optical fiber according to the present invention comprises a glass optical fiber coated with at least two coating layers, soft and hard layers. The optical fiber is further coated by a colored resin to make a colored optical fiber. The hard layer and the color layer of the colored optical fiber have a free volume radius of at least 0.290 nm according to positron annihilation lifetime spectroscopy.

A colored optical fiber whose transmission loss hardly increases even in a high humidity condition or water-immersed condition is provided. The colored optical fiber according to the present invention is a colored optical fiber having a colored coating layer on a circumference of an optical fiber having at least two coating layers on a circumference of a glass optical fiber, characterized in that a difference in each amount of thermal expansion in an outer diameter direction between the optical fiber and a coating layer obtained by removing the glass optical fiber from the optical fiber in a temperature range from &#x2212;100&#xb0; C. to 100&#xb0; C. is 1.8 &#x3bc;m or less.

Colored optical fiber and evaluation method thereof

Digital video disc recorder

In a cell library database, timing verification is conducted on an LSI which exists in a variable power supply system capable of changing the source voltage arbitrarily and which includes logic delay information associated with a plurality of source voltages. The database is configured, for example, so that the voltage information V of the source is represented in multiple bits V [1:0] and delay times Alh (Vlh) to Bhl (Vhh) between the time input signals A and B are each changed and the time the output signal Y changes are described for respective pieces of source voltage information LH (1.2 V), HL (1.5 V) and HH (1.8 V). This allows timing verification in the variable source system which operates with the source voltage changed dynamically.

Cell library database and timing verification and withstand voltage verification systems for integrated circuit using the same

A high-precision and high-performance level shift circuit, which is not adversely influenced by an offset error owned by an operational amplifier. Two sets of resistors () and () having the same resistance values, which are connected between differential output terminals and an operational amplifier () for performing a level shift control are provided. A feedback operation is carried out in such a manner that an average voltage of each of differential outputs () and () is continuously made coincident with a DC reference potential () irrespective of an offset error of an output-purpose operational amplifier, and a level shift function having a small error is realized. Two resistors (and) are series-connected between a differential output of a digital/analog converter () and a level shift circuit to output a voltage outside an output dynamic range of the digital/analog converter ().

Growing community of inventors

Tokyo, Japan

Kouji Mochizuki