OPTICAL ANALYZER AND WAVELENGTH STABILIZED LASER DEVICE FOR ANALYZER

• US 20110019183A1
• Filed: 03/27/2009
• Published: 01/27/2011
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: Horiba Limited
• Original Assignee: Horiba Limited
• Inventors: Ido, Takuya, Mimura, Susumu, Ukon, Juichiro
• Granted Patent: US 9,116,116 B2
• Time in Patent Office: Days
• US Class Current: 356/51
• CPC Class Codes: G01J 3/108 for measurement in the infrared range
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 21/39 using tunable lasers
• CPC Class Codes: G01N 21/7703 using reagent-clad optical fibres or optical waveguides using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B
• CPC Class Codes: G01N 2201/0231 Thermostating
• CPC Class Codes: H01S 5/02325 Mechanically integrated components on mount members or optical micro-benches
• CPC Class Codes: H01S 5/024 Arrangements for thermal management
• CPC Class Codes: H01S 5/02415 by using a thermo-electric cooler [TEC], e.g. Peltier element
• CPC Class Codes: H01S 5/06213 Amplitude modulation
• CPC Class Codes: H01S 5/0687 Stabilising the frequency of the laser

Abstract

Provided is an optical analyzer which can promote enhancement of measurement sensitivity, cost reduction, size reduction, structural flexibility, disturbance resistance, and the like, at the same time. A laser device to be used in such optical analyzer is also provided. An optical analyzer comprises a laser light source (2); a wavelength selection element (3) for selecting and leading out light having a wavelength substantially equal to the absorption wavelength of an analysis object from among light outputted from the laser light source (2); an optical detection means (5) for detecting the intensity of light red out from the wavelength selection element (3); and a drive current control means (6) for increasing or decreasing the drive current of the laser light source (2) near a specified current value thereof for outputting light of the absorption wavelength, and setting the drive current at such a current value as the intensity of light detected by the optical detection means (5) has a peak value. The laser light source (2), the wavelength selection element (3), and the optical detection means (5) are mounted on a single substrate (11) which can regulate the temperature to a constant level.

Claims

1. A laser device for analyzer comprising

a laser light source that outputs light having a wavelength near an absorption wavelength of an analysis object,

a wavelength selection element that receives a part of the light output from the laser light source and that selects and leads out the light having a wavelength substantially equal to the absorption wavelength of the analysis object from among wavelengths of the light,

a light detection device that detects intensity of the light led out from the wavelength selection element,

a drive electric current control device that increases or decreases a drive electric current of the laser light source near a specified electric current value to output the light of the above-mentioned absorption wavelength by the laser light source so as to set the drive electric current at an electric current value at a time when the intensity of the light detected by the light detection device becomes a peak, and

a single substrate that is equipped with the laser light source, the wavelength selection element and the light detection device and that can adjust the temperature at a constant level.

2. The laser device for analyzer described in claim 1, wherein the single substrate makes use of a peltier module as being a temperature adjusting device.

3. The laser device for analyzer described in claim 1, wherein the laser light source is a semiconductor laser.

4. The laser device for analyzer described in claim 1, wherein the wavelength selection element is arranged at a position to receive leaked light leaked from a reverse side of a major light ejection exit of the laser light source.

5. The laser device for analyzer described in claim 1, wherein the laser light source ejects the light of mid-infrared area.

6. The laser device for analyzer described in claim 1, wherein a return light inhibiting device that inhibits return light returned from the wavelength selection element to the laser light source is arranged on an optical path between the laser light source and the wavelength selection element.

7. An optical analyzer that measures a concentration or a density of an analysis object based on intensity of light that is ejected from a laser light source and that passes the analysis object, wherein provided are a fiber-type analyzing part that is so arranged to refract and propagate the light introduced into inside thereof and to introduce the analysis object on a propagation path of the light, a wavelength selection element whose selective wavelength is set in an absorption wavelength band of the analysis object, a measurement light detection device that detects the intensity of the light selected by the fiber-type analyzing part, and a reference light detection device that detects the intensity of the light led out from the wavelength selection element, and is characterized by that an optical fiber connects between the laser light source and the fiber-type analyzing part, between the fiber-type analyzing part and the measurement light detection device, between the laser light source and the wavelength selection element, and between the wavelength selection element and the reference light detection device respectively.

8. The optical analyzer described in claim 7, wherein the laser light source is a semiconductor laser that ejects the light of near-infrared area.

9. The optical analyzer described in claim 7, and further comprising a temperature adjusting mechanism for the laser light source and a temperature adjusting mechanism for the wavelength selection element.

10. The optical analyzer described in claim 7, wherein it is so arranged that reflected light of the wavelength selection element is introduced to the reference light detection device, and is characterized by that an isolator that inhibits the reflected light from returning to the laser light source is arranged along the optical fiber.

11. The optical analyzer described in claim 10, wherein another optical fiber is bifurcated from the optical fiber connecting the laser light source and the fiber-type analyzing part so as to be connected to the wavelength selection element, and a further different optical fiber is bifurcated from the above-mentioned another optical fiber so as to be connected to the reference light selection element.

12. The optical analyzer described in claim 7, wherein the fiber-type analyzing part is provided with a groove with a bottom or a bore with a bottom that enables to introduce the analysis object into a side peripheral surface of the optical fiber, and the groove with the bottom or the bore with the bottom is so arranged to reach a part of the light propagation area in the optical fiber.

13. The optical analyzer described in claim 12, wherein the fiber-type analyzing part is curved.

14. The optical analyzer described in claim 7, and comprising multiple numbers of the laser light sources whose wavelength differs and multiple numbers of the wavelength selection elements that correspond to each of the laser light sources.

15. An optical analyzer that measures a concentration or a density of an analysis object based on intensity of light that is ejected from a laser light source and that passes the analysis object, wherein provided are

a fiber-type analyzing part that is so arranged to refract and propagate the light introduced into inside thereof and to introduce the analysis object on a propagation path of the light, a reference cell inside of which a reference material having substantially the same optical characteristics as that of the analysis object is held, a measurement light detection device that detects the intensity of the light selected by the fiber-type analyzing part, and a reference light detection device that detects the intensity of the light led out from the reference cell, and is characterized by that

an optical fiber connects between the laser light source and the fiber-type analyzing part, between the fiber-type analyzing part and the measurement light detection device, between the laser light source and the reference cell, and between the reference cell and the reference light detection device respectively.