Invention Grant
- Patent Title: Method for producing optical fiber preform
- Patent Title (中): 光纤预制棒的制造方法
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Application No.: US13356984Application Date: 2012-01-24
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Publication No.: US08839646B2Publication Date: 2014-09-23
- Inventor: Tetsuya Haruna , Masaaki Hirano , Yoshiaki Tamura
- Applicant: Tetsuya Haruna , Masaaki Hirano , Yoshiaki Tamura
- Applicant Address: JP Osaka-shi, Osaka
- Assignee: Sumitomo Electric Industries, Ltd.
- Current Assignee: Sumitomo Electric Industries, Ltd.
- Current Assignee Address: JP Osaka-shi, Osaka
- Agency: Drinker Biddle & Reath LLP
- Priority: JP2011-015287 20110127
- Main IPC: C03C25/60
- IPC: C03C25/60 ; C03B37/018 ; C03B37/014 ; C03B37/012

Abstract:
There is provided a method for producing an optical fiber preform used in producing an optical fiber having low attenuation. The production method includes (1) a rod formation step of forming a glass rod of a silica glass containing an alkali metal element, the average concentration of the alkali metal element being 5 at·ppm or more, (2) a heat treatment step of heat-treating the glass rod, (3) a core part formation step of forming an alkali metal element-free silica glass layer having a chlorine concentration of 6000 at·ppm or more around the perimeter of the glass rod heat-treated in the heat treatment step to form a core part including the glass rod and the silica glass layer, and (4) a cladding part formation step of forming a cladding part of a silica-based glass having a lower refractive index than the core part around the perimeter of the core part.
Public/Granted literature
- US20120192593A1 METHOD FOR PRODUCING OPTICAL FIBER PREFORM Public/Granted day:2012-08-02
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