US 2006/0067616 A1 · Pseudo slant fiber bragg grating, multiple series fiber bragg grating, optical fiber type coupler and optical connector

Abstract

An optical fiber 4 having a clad diameter of 125 μm is made by adding Ge to a core 41 having a core diameter of 8 μm and a relative refractive index difference of 0.3 %, and two refractive index grating portions 41a and 41b having a slant angle of 2° are formed in series in the optical fiber 4 by a phase mask method using KrF excimer laser (λ=248 nm). The central period (2Λ) of the phase mask of a chirped grating is 1,140 nm, the chip rate (C) of the period is 1.2 nm/mm, the length (G) of the first and second index grating portions 41a and 41b is 8 mm, the effective refractive index of the first and second index grating portions 41a and 41b is 1.447, the refractive index modulation is 3×10−3, and the gap between the first and second index grating portions 41a and 41b is 1 mm.

Claims16

Dependent claims

A quasi slanted fiber Bragg grating comprising a refractive index grating portion, formed on the core of an optical fiber having a principal axis, to have a grating vector slanted with respect to the fiber principal axis to thereby reflect incident light selectively with a reflection factor of 90% or more and to make the loss due to the coupling to a clad mode, less than 5 dB.

A multiple series fiber Bragg grating comprising:

a first refractive index grating portion, formed on the core of an optical fiber having a principal axis, to have a grating vector slanted with respect to the fiber principal axis to thereby reflect incident light selectively with a reflection factor of 90% or more and to make the loss due to the coupling to a clad mode, less than 5 dB;
a second refractive index grating portion formed on the core of an optical fiber to have a grating vector slanted with respect to the fiber principal axis to thereby reflect incident light selectively with a reflection factor of 10% or more and to make the loss due to the coupling to a clad mode, 5 dB or more;
a third refractive index grating portion formed on the core of an optical fiber to have a grating vector in parallel with the fiber principal axis thereby to reflect incident light selectively with a reflection factor of substantially 100% or more and to make the loss due to the coupling to a clad mode, less than 5 dB;
and
a fourth refractive index grating portion having a grating vector slanted with respect to the fiber principal axis to thereby reflect incident light selectively with a reflection factor less than 10% and to make the loss due to the coupling to a clad mode, 5 dB or more.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application

10/523,215Filed 21 Aug 2003

Priority

JP 2002-24179822 Aug 2002

Published

30 Mar 2006

Term ends

Not estimatedThe source records don’t support an estimate.

Classification8 codes

G02B 6/02085
Characterised by their structure, wavelength response: characterised by the grating profile, e.g. chirped, apodised, tilted, helical
G02B 6/3846
Details of mounting fibres in ferrules; Assembly methods; Manufacture: with fibre stubs
G02B 6/02138
Using beam interference: based on illuminating a phase mask
G02B 6/3826
Of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres: characterised by form or shape

Pseudo slant fiber bragg grating, multiple series fiber bragg grating, optical fiber type coupler and optical connector

Life of this patent

Pseudo slant fiber bragg grating, multiple series fiber bragg grating, optical fiber type coupler and optical connector

Life of this patent

Abstract

Claims16