Optical isolator and method for assembling same
AssigneeNamiki Precision Jewel Co., Ltd.
InventorsYoshihiro Konno, Hiroshi Kume
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Abstract
In optical isolators composed of a polarizer, an analyzer, a Faraday rotator and permanent magnet for magnetizing the Faraday rotator for the Faraday effect, this invention enables controlling of the maximum isolation temperature in the 0.degree. to 70.degree. C. temperature range. When assembling the device at room temperature, the Faraday rotator's wavelength-dependence characteristics are used for this purpose. By varying the wavelength during the assembly and adjustment process by .DELTA..lambda. from the wavelength at the device will be used, it is possible to set the temperature at which maximum isolation will be realized.
Claims5
An optical transmission arrangement comprising a source of light of wavelength .lambda. and an optical isolator having a polarizer, an analyzer, a Faraday rotator formed of a material having a range of optical properties which decrease symmetrically as a function of temperature from a temperature at which a maximum value of said optical properties occurs and a permanent magnet which magnetizes the Faraday rotator into a Faraday rotation angle of approximately 45.degree.;
- wherein said optical isolator has been assembled into an optical position, in which the temperature at which said maximum value of said optical properties occurs is room temperature, using a source of light having an adjusted assembly wavelength which minutely differs from the wavelength .lambda. by a value .DELTA..lambda. in order to shift the temperature at which said maximum value of said optical properties occurs from said room temperature to a temperature in the middle of a temperature range in which the optical isolator is used with the light source of wavelength .lambda..
A method of assembling an optical isolator;
- having a polarizer, an analyzer a Faraday rotator formed of a material having a range of optical properties which decrease symmetrically as a function of temperature from a temperature at which a maximum value of said optical properties occurs and a permanent magnet which magnetizes the Faraday rotator into a Faraday rotation angle of approximately 45.degree., for use with a light source of light of wavelength .lambda. comprising the steps of:
- A) determining a temperature range within which the optical isolator will be used;
- B) selecting a temperature in the middle of the temperature range determined;
- C) assembling the optical isolator into an optical position ,in which said maximum value of said optical properties occurs at room temperature, using a light source of a wavelength which differs from wavelength .lambda. by an amount .+-..DELTA..lambda. which will shift the temperature at which said maximum value of said optical properties occurs from said room temperature to the selected temperature when the optical isolator is used with the light source of wavelength .lambda..
Dependencies are inferred from the claim text.