OPTICAL COUPLER AND OPTICAL OUTPUT DEVICE

• Main Authors: TSUKIJI NAOKI, EMORI YOSHIHIRO, TOMIYASU TAKAHIRO, ISHII HIROTATSU
• Format: Patent
• Language: English; Japanese
• Published: 12.11.2020
• Subjects: BASIC ELECTRIC ELEMENTS; DEVICES USING STIMULATED EMISSION; ELECTRICITY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

To provide an optical coupler suitable for the output of a high power laser beam, and an optical output device using the same.SOLUTION: An optical coupler 10 includes a plurality of input optical fibers 1 and an output optical fiber 2. The plurality of input optical fibers 1 are bundled on the tip side to form a bundle part 1c; the tip 1ca of the bundle part 1c is connected to the output optical fiber 2; the bundle part 1c includes a taper part 1cb tapered so that each of the plurality of input optical fiber 1 reduces a cross sectional area at the tip 1ca; and when setting: the numerical aperture of the output optical fiber 2 to NAout; each numerical aperture of the plurality of input optical fibers 1 to NAin; the total cross sectional area of the plurality of input optical fibers 1 on the base end side from the taper part 1cb to ΣAi; and the cross sectional area of the bundle part 1c at the tip 1ca to A, the following formula (NAout/NAin)2<ΣAi/A is satisfied.SELECTED DRAWING: Figure 1 【課題】高パワーのレーザ光の出力に適する光結合器およびこれを用いた光出力装置を提供すること。【解決手段】光結合器１０は、複数の入力光ファイバ１と、出力光ファイバ２と、を備え、複数の入力光ファイバ１は、先端側が束ねられて束部１ｃを構成しており、束部１ｃの先端部１ｃａが出力光ファイバ２に接続されており、束部１ｃは、複数の入力光ファイバ１のそれぞれが先端部１ｃａで断面積が縮小するようにテーパ状になっているテーパ部１ｃｂを有しており、出力光ファイバ２の開口数をＮＡｏｕｔ、複数の入力光ファイバ１のそれぞれの開口数をＮＡｉｎ、テーパ部１ｃｂよりも基端側における複数の入力光ファイバ１の断面積の総計をΣＡｉ、先端部１ｃａでの束部１ｃの断面積をＡとすると、下記式（ＮＡｏｕｔ／ＮＡｉｎ）２＜ΣＡｉ／Ａが成り立つ。【選択図】図１