JP2015514306A5

JP2015514306A5 -

Info

Publication number: JP2015514306A5
Application number: JP2015500633A
Authority: JP
Filing date: 2013-03-14
Publication date: 2016-03-17
Anticipated expiration: 2033-03-14

Description

ＯＦＤＲの一例では、光は２００ＴＨｚ（波長１５００ｎｍ）の公称周波数からマイクロ秒当たり１０ＭＨｚの速度で光周波数が着実に増加し、この周波数掃引は１０００マイクロ秒の期間維持され得る。１ｋｍの距離でファイバ内の不連続部（例えば、欠陥、コネクタ、端面等）から反射される光は、約１０μｓの往復遅延を発生する（ファイバ内の光の速度のための典型的な値を使用して）。したがって、光周波数掃引の間、反射光は、生成された光周波数が１００ＭＨｚ遅かった時のレーザ光源からのものであろう。反射光と現在のレーザ出力周波数との間のこの特定の周波数差は、掃引が維持される限り、この距離からの全ての光の特性であろう。他の全ての距離からの反射光は、異なる特性の周波数差を有することになる。
In one example of OFDR, light steadily increases in optical frequency from a nominal frequency of 200 THz (wavelength 1500 nm) at a rate of 10 MHz per microsecond, and this frequency sweep can be maintained for a period of 1000 microseconds. Light reflected from discontinuities in the fiber (eg, defects, connectors, end faces, etc.) at a distance of 1 km will generate a round trip delay of about 10 μs (typical values for the speed of light in the fiber). Use). Thus, during the optical frequency sweep, the reflected light will be from the laser source when the generated optical frequency is 100 MHz slow. This particular frequency difference between the reflected light and the current laser output frequency will be a property of all light from this distance as long as the sweep is maintained. Reflected light from all other distances will have different characteristic frequency differences .

Claims

A laser light source configured to output laser light at a target frequency;
Comprising the actual frequency at a certain instant of the laser light source, a measuring unit for deriving the measured deviations between the target frequency of the laser light source,
The measurement unit further comprises:
Comprising first and second laser paths for splitting the laser light output by the laser light source, the first and second laser paths having different lengths;
Equipped with a detector to observe the interference pattern,
When the laser light traveling along the first laser path is recombined with the laser light traveling along the second laser path, the interference pattern is generated,
The measurement unit derives the measured deviation between the actual frequency and the target frequency based on the observed interference pattern;
Based on the measured deviation between the actual frequency and the target frequency, the feedback control that is configured to control the laser light source so as to maintain a constant frequency of the laser output from the laser light source comprising a unit, thereby, device frequency of the laser beam transmitted from the laser light source is adjusted to the target frequency of the laser light source.

The apparatus of claim 1.
The feedback control unit includes an infinite impulse response filter configured to compensate for the characteristics of the measurement unit used for frequency measurement.

An OFDR device,
Comprising the apparatus of claim 1 ,
The OFDR apparatus outputs laser light from the laser light source to a point of the optical component to be tested that is spaced from the laser light source, and the instantaneous frequency of the output laser light and the laser light reflected from the point Configured to measure the frequency difference between
The feedback control unit maintains a constant frequency difference between the frequency of the laser light output from the laser light source and the instantaneous frequency reflected from the point, whereby the frequency difference is An OFDR device configured to characterize the reflectance profile of the optical component in direct proportion to the distance to a point, and wherein the amplitude of the reflected laser light is proportional to the reflectance at the point.

The OFDR device according to claim 3 ,
The optical component is an OFDR device that is at least one of an optical fiber, an optical coupler, an optical connector, an optical switch, an optical integrated optical waveguide, liquid, air, and free space.

The OFDR device according to claim 4 ,
The OFDR apparatus, wherein the reflectance profile of the optical fiber is measurable with a length exceeding the reflectance profile measurable by the laser light source not controlled by the feedback control unit.

The OFDR device according to claim 4 ,
The OFDR apparatus, wherein the reflectance profile of the optical fiber can be measured in one measurement at a distance greater than 1 meter.

The apparatus of claim 1.
The feedback control unit is configured to stabilize the actual frequency range of the laser light source to the target frequency.

The apparatus of claim 1.
The control of the laser light source device which comprises adjusting the temperature of the laser light source by a magnetic refrigeration material.

The apparatus of claim 1.
The control of the laser light source includes adjusting the temperature of the laser light source by a current tuning mechanism.