Optical attenuator and optical attenuator module
AssigneeSantec Corporation
InventorsDaikou Tei, Naoyuki Mekada, Masaharu Okada
Life of this patent
Estimating the term…
Abstract
In order to realize an optical attenuator which has an attenuation factor independent of the wavelength of incident light, a glass substrate is used in an attenuator plate, and the glass substrate is formed in a tapered section so that its incident and exit planes may not be parallel to each other. On one side thereof, a metal film corresponding to the attenuation factor is formed. Also one side of the glass substrate is covered with an antireflection coating for canceling the wavelength dependence of the metal film. Thereby ripple of attenuation factor due to wavelength can be eliminated, and the wavelength dependence may be minimized.
Claims20
An optical attenuator comprising:
- a transparent glass substrate having a specified taper so that the incident plane and exit plane may not be parallel to each other;
- and
- a metal film formed on one side of said transparent glass substrate, for attenuating the incident light by a specified attenuation factor.
An optical attenuator module comprising:
- a first light reflecting unit for reflecting incident light;
- an optical attenuator composed of a transparent glass substrate having a specified taper so that the incident plane and exit plane may not be parallel to each other, and a metal film formed on one side thereof for attenuating the light reflected by said first light reflecting unit by a specified attenuation factor;
- and
- a second light reflecting unit for reflecting the light passing through said optical attenuator.
An optical attenuator module comprising:
- a first optical branching unit for branching part of incident light and passing the rest;
- an optical attenuator composed of a transparent glass substrate having a specified taper so that the incident plane and exit plane may not be parallel to each other, and a metal film formed on one side thereof for attenuating the light passing through said first optical branching unit by a specified attenuation factor;
- a second optical branching unit for branching part of the light passing through said optical attenuator, and passing the rest;
- a first photo detector detecting one of the branched light by said first branching unit;
- a second photo detector detecting one of the branched light by said second branching unit;
- a level detector for detecting the reception levels of said first and second photo detectors;
- and
- a display unit for displaying the reception levels detected by said level detector.
An optical attenuator module comprising:
- a first optical branching unit for branching part of incident light and passing the rest;
- an optical attenuator composed of a transparent glass substrate having a specified taper so that the incident plane and exit plane may not be parallel to each other, a metal film formed on one side thereof for attenuating the light passing through said first optical branching unit by an attenuation factor depending on the incident position, and an antireflection coating applied at least on one side of said transparent glass substrate for compensating for wavelength dependence of attenuation factor due to said metal film;
- a second optical branching unit for branching part of the light passing through said optical attenuator, and passing the rest;
- a first photo detector detecting one of the branched light by said first optical branching unit;
- a second photo detector detecting one of the branched light by said second optical branching unit;
- a level detector for detecting the reception levels of said first and second photo detectors;
- and
- a display unit for displaying the reception levels detected by said level detector.
Dependencies are inferred from the claim text.