JP2015090951A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device that has simple constitution and can be stabilized over a wide wavelength band with high precision.SOLUTION: A wavelength-stabilized light source (light source device) 100 includes: a wavelength discriminator 6 which includes a sealed container 60 where a standard material that light emitted from the light source 1 is transmitted through is charged, and discriminates the wavelength of the light; an optical detector 8 which detects the light discriminated by the wavelength discriminator 6; an error signal arithmetic part 9 which finds an error signal using the detection signal of the optical detector 8; and a control part 101 which controls the wavelength of the light source 1 based upon the error signal from the error signal arithmetic part 9. Here, the standard material contains two or more molecular species, and at least two of the molecular species have a region where absorption bands as absorption line groups of the molecular species overlaps, and the absorption factor of the absorption line at a peak of the absorption band of at least one molecular species is 96% or larger in the region where the absorption bands overlap.

Description

  The present invention relates to a light source device that stabilizes the wavelength of light from a light source.

A wavelength-stabilized light source (light source device) is used for calibrating the wavelength (frequency) of a laser for high-accuracy measurement interferometers and a semiconductor laser for optical communication such as high-density wavelength division multiplexing (DWDM). . A wavelength-stabilized light source generally includes a wavelength discriminator that converts the wavelength change of the stabilized original light source into a change in light intensity. And as a wavelength discriminator of a wavelength stabilized light source that requires higher accuracy, an etalon or a gas cell in which gas molecules or gas atoms are enclosed is used, especially when stability is required even in the long term. A gas cell that is resistant to environmental changes is used. However, when a gas cell is used for the wavelength discriminator, the wavelength that can be stabilized is determined by the absorption lines of the encapsulated molecules. Therefore, Patent Document 1 discloses a wavelength-stabilized light source (optical frequency-stabilized light source) that increases the number of wavelengths that can be stabilized using a mixed gas cell or a plurality of gas cells in which the types of gas molecules to be sealed are increased. . In this wavelength-stabilized light source, _{two of} NH ₃ , ¹⁵ NH ₃ , C ₂ H ₂ , ¹³ C ₂ H ₂ , HCN, H ¹³ CN, HC ¹⁵ N, and H ¹³ C ¹⁵ N are included in the light absorption cell. Encloses various types of molecular species and stabilizes the oscillation frequency with a larger number of frequencies. Patent Document 2 discloses a wavelength-stabilized light source (variable wavelength light source) that guarantees the peak of the transmission spectrum of the etalon with a reference laser stabilized to an absorption line when an etalon is used for the wavelength discriminator. Yes.

Japanese Patent Publication No. 6-14571 Japanese Examined Patent Publication No. 7-63102

However, since the wavelength-stabilized light source shown in Patent Document 1 uses a gas absorption line as a wavelength reference, even in the same absorption band, the difference in absorption between the central portion and the peripheral portion of the absorption band becomes large. Therefore, in order to realize highly accurate stability, only the center part of the absorption band (absorption line group spectrum) can be used. For example, in a 1.5 μm band molecular gas cell used for a light source for optical communication, the width of the absorption band that is 20% or more of the absorption rate that is the peak of the absorption band is 27.6 nm with C ₂ H ₂ . (151.20 to 1540.83 nm, NIST, SRM2517a). ^Similarly, the ^H 13 CN, a 35.0nm (1527.63~1562.56nm, NIST, SRM2519a) about. NIST is an abbreviation for National Institute of Standards and Technology (National Institute of Standards and Technology). That is, a band covering 1530 to 1565 nm (C band) and 1565 to 1625 nm (L band), which are DWDM bands of optical communication, cannot be obtained only by the absorption line at the center of the absorption band. Further, the wavelength stabilized light source disclosed in Patent Document 2 requires a plurality of control systems such as a control system that stabilizes the etalon as a reference laser and a control system that stabilizes the original light source in the etalon, so that the overall configuration becomes complicated. .

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a light source device that can be stabilized in a wide wavelength band with a simple configuration and with high accuracy.

  In order to solve the above problems, the present invention is a light source device that stabilizes the wavelength of light emitted from a light source, and includes a sealed container that encloses a standard material that transmits light, and discriminates the wavelength of light. A wavelength discriminator, a photodetector for detecting the light discriminated by the wavelength discriminator, an error signal calculation unit for obtaining an error signal using a detection signal from the photodetector, and an error signal from the error signal calculation unit And a control unit that controls the wavelength of the light source, and the standard material includes two or more molecular species, and at least two of the molecular species are absorption line groups of the molecular species In the region where the bands overlap and the absorption band overlaps, the absorption rate of the absorption line at the peak of the absorption band of at least one molecular species is 96% or more.

  According to the present invention, for example, it is possible to provide a light source device that can be stabilized in a wide wavelength band with a simple configuration and with high accuracy.

It is a figure which shows the structure of the wavelength stabilization light source which concerns on 1st Embodiment of this invention. It is a graph which shows the absorption spectrum of the wavelength discriminator in 1st Embodiment. It is a graph which shows the characteristic of the wavelength discriminator in 1st Embodiment. It is a graph which shows the relationship between the absorption line in 1st Embodiment, and an error signal. It is a figure which shows the structure of the wavelength stabilization light source which concerns on 2nd Embodiment of this invention. It is a graph which shows the absorption spectrum of the wavelength discriminator in 2nd Embodiment. It is a graph which shows the characteristic of the wavelength discriminator in 2nd Embodiment. It is a graph which shows the characteristic of the spectrum filter in a 2nd embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
First, the light source device according to the first embodiment of the present invention will be described. FIG. 1 is a schematic diagram illustrating a configuration of a wavelength-stabilized light source 100 as a light source device according to the present embodiment. The wavelength stabilized light source 100 includes a light source 1 as an original light source to be stabilized, an optical demultiplexer 2, an optical modulator 3, a modulation signal generator 4, a collimator lens 5, and a wavelength discriminator 6. , Photodetector 8, error signal calculation unit 9, control unit 101, and wavelength converter 110.

  A light source (wavelength tunable laser light source) 1 is a DFB laser module in which a plurality of DFB (distributed feedback) semiconductor lasers are integrated as the wavelength tunable laser and can oscillate in the entire C band. As the light source 1, an external resonator type semiconductor laser, a wavelength tunable fiber laser, or the like may be used. Hereinafter, the first stabilization wavelength of the light source 1 is assumed to be the wavelength λ1, and the wavelength reference center wavelength of the wavelength λ1 is assumed to be the wavelength λ1c. The optical demultiplexer 2 is an optical fiber type demultiplexer that splits the light emitted from the light source 1 into two paths. One light is output to the output unit 120 and the other light is input to the optical modulator 3. Light guide. The optical modulator 3 is an optical fiber type phase modulator (LN phase modulator) using a waveguide type lithium niobate which is a highly efficient electro-optic modulator (EOM). The optical modulator 3 may be a bulk type electro-optic modulator. The modulation signal generator 4 is an electric circuit that can generate a sine signal with an appropriate frequency and amplitude, drives the optical modulator 3, and outputs the same signal as a reference signal to an error signal calculation unit 9 described later. . The collimator lens 5 is a converging lens that converts light transmitted from the optical modulator 3 through a fiber and emitted into space into a parallel light flux.

The wavelength discriminator (wavelength reference element) 6 includes a gas cell 60 and mirrors 61 and 62 that reciprocate incident light in the gas cell 60, and the wavelength of the light source 1 modulated by the light modulator 3 depends on the absorption spectrum. Discriminate. Specifically, the wavelength discriminator 6 changes the intensity of the incident light according to the wavelength shift from the reference wavelength. The gas cell 60 is an optically transparent sealed container in which two kinds of molecular species (hydrogen cyanide gas isotopes) of H ¹² CN and H ¹³ CN are sealed as a standard substance, and light enters or exits. The window portion is coated with an antireflection film. More specifically, the gas cell 60 may be a quartz glass tube having a length of 200 mm sealed with 2.6 Torr of H ¹² CN and 13.4 Torr of H ¹³ CN. The mirrors 61 and 62 are silver film mirrors having high reflectivity in the near-infrared band. For example, the mirrors 61 and 62 are arranged so as to be adjusted to an angle such that the light that has become a parallel light beam by the collimator lens 5 passes through the gas cell 60 five times. Has been. That is, according to this configuration, the wavelength discriminator 6 functions as a wavelength discriminator equivalent to the gas cell 60 having a cell length (execution distance through which light passes through the sealed container) of 1000 mm. Note that the cell length is not limited to only 1000 mm, and is optimal in the present embodiment if it is 1000 mm or more.

FIG. 2 is a graph showing an absorption spectrum of the wavelength discriminator 6 in the present embodiment. In FIG. 2, with respect to the absorption rate (calculated value) on the horizontal axis, the dotted line indicates the absorption line of H ¹² CN and the solid line indicates the absorption line of H ¹³ CN. Since the pressure of H ¹³ CN is higher than the pressure of H ¹² CN, the wavelength discriminator 6 increases the absorption rate of the entire absorption band. Here, the “absorption band” refers to an absorption line group spectrum formed by an envelope connecting peaks of fine absorption lines of molecules.

FIG. 3 is a graph showing the characteristics of the wavelength discriminator 6 in the present embodiment. In FIG. 3, with respect to the pressure on the horizontal axis, the left vertical axis represents the performance coefficient of the absorption line, and the right vertical axis represents the absorption rate. Moreover, each absorption line is with respect to the sealing pressure in a hydrogen cyanide gas cell having a cell length of 1000 mm. The performance coefficient of the absorption line is an amount proportional to the slope of an error signal in FIG. 4B described later, and the higher the value, the more suitable the wavelength reference is. In addition, the performance coefficient of a strong absorption line at an optimum pressure is standardized as 1, and in this embodiment, a wavelength reference having a performance coefficient of 0.5 or more is set as a highly accurate wavelength reference. In FIG. 3, the values of the three series Strong, Weak, and Middle are respectively a strong absorption line at the peak of the absorption band, a weak absorption line at the bottom of the absorption band, and a medium absorption line in the middle. The performance coefficient is plotted with a solid line, and the absorption rate is plotted with a dotted line. However, the absorption rate of the medium absorption line is not shown. Further, since H ¹² CN and H ¹³ CN have similar absorption band characteristics, FIG. 3 representatively shows the characteristics of absorption lines of both isotopes.

2 and FIG. 3, first, the performance coefficient of the absorption line at the bottom of the absorption band of H ¹³ CN near 1565 nm in FIG. 2 is the value of the Weak series at a pressure of 13.6 Torr in FIG. Corresponding to about 0.5. In contrast, the performance coefficient of the strong absorption line of H ¹³ CN in the band from 1535.54 nm to 1538.52 nm (R band) in FIG. 2 is the Strong series value at the pressure of 13.6 Torr in FIG. Corresponding to approximately 0.04. The same applies to the band from 1545.96 nm to 1549.73 nm (P band). Therefore, this band cannot be used as a highly accurate wavelength reference. On the other hand, as shown in FIG. 2, there is an overlap in the absorption band of the ^H 13 CN and ^H 13 CN of 1.5μm ^band, the band of strong absorption lines of ^H 13 ^{CN, H} 12 CN strong absorption lines or There is a moderate absorption line. Here, “there is an overlap between absorption bands” means that the envelopes of the two absorption bands share a wavelength band. In particular, between molecules where there are two envelope peaks (P branch envelope peak and R branch envelope peak), there is a peak of the other molecule between the two peaks of one molecule. Refers to cases. The performance coefficients of these absorption lines of H ¹² CN correspond to the values of the Strong series and the Middle series at a pressure of 2.6 Torr in FIG. 3 and are 0.58 and 0.87, respectively. Therefore, the absorption line of H ¹² CN can be used in place of the wavelength reference of the band of strong absorption line of H ¹³ CN here. Here, (Table 1) shows absorptance of typical absorption lines of the wavelength discriminator 6 in the present embodiment.

In the present embodiment, the partial pressure of H ¹³ CN is increased to 17 times (maximum 13.6 Torr or more) of the optimum pressure 0.8 Torr in the absorption line having a strong absorption band peak (absorption line numbers: R8, P8), The absorption rate is 96% or more. Thereby, the absorption factor of the absorption band skirt (absorption line number: P27) can be increased to 24.6% as shown in (Table 1). Similarly, in the wavelength discriminator 6, the absorption is 24% or more (corresponding to the absorption of a weak absorption line that can be used as a highly accurate wavelength reference with a performance coefficient of 0.5 or more shown in FIG. 3). The band of the line is from 1521.65 nm to 1564.44 nm. Therefore, the wavelength discriminator 6 can provide a highly accurate wavelength reference in a wide band covering a part of the S band (from 1460 nm to 1530 nm) and almost the entire C band.

  The photodetector 8 is an InGaAs photodiode having a wavelength band of 1.5 μm. The photodetector 8 may be an avalanche photodiode as long as it is sensitive to the wavelength of the light source 1. The error signal calculation unit 9 is an electric circuit including a synchronous detector, a phase adjuster, and the like, and uses the reference signal from the modulation signal generator 4 and the detection signal from the photodetector 8 to use the wavelength λ1 of the light source 1. A voltage signal (error signal) proportional to the difference between the center wavelength λ1c and the center wavelength λ1c is obtained and output. The control unit 101 is a computer on which an integrated circuit such as a PC or an FPGA (Field Programmable Gate Array) is mounted, and feeds back a control signal to the wavelength converter 110. The output signal of the photodetector 8 may be AD converted, and the error signal calculation unit 9 and the control unit 101 may be mounted on the same PC or FPGA as a digital control system. The wavelength converter 110 is an LD driver that can arbitrarily select and set a driving element in the light source 1 and its driving current and operating temperature. Thereby, the light source (DFB laser module) 1 can convert (change) the oscillation wavelength.

Next, wavelength stabilization control by the wavelength stabilization light source 100 will be described. First, at the start of wavelength stabilization, the wavelength converter 110 illuminates the light source 1 with a drive element, an operating temperature, and an initial drive current such that the start wavelength (initial wavelength) substantially matches the wavelength reference center wavelength λ1c. Launch. The driving element, operating temperature, and initial driving current at this time are determined based on the wavelength temperature characteristic and wavelength current characteristic of each driving element in the light source 1 measured in advance. The light emitted from the light source 1 is frequency-modulated (that is, wavelength-modulated) at the modulation frequency f _M of the modulation signal generator 4 via the optical modulator 3, converted into a parallel light flux by the collimator lens 5, and then the wavelength discriminator. 6 is incident. The light incident on the wavelength discriminator 6 is absorbed inside and is intensity-modulated according to the wavelength λ1 of the light source 1 and the amount of wavelength modulation. The light transmitted through the gas cell 60 is converted by the photodetector 8 into a voltage signal, it is synchronized detection on the modulation frequency f _M of the modulation signal generator 4 by the error signal calculation unit 9, and is converted into an error signal.

  FIG. 4 is a graph schematically showing an absorption spectrum for each absorption line of the wavelength discriminator 6 and an error signal corresponding to the absorption spectrum. FIG. 4 (a) shows the absorption spectrum, and FIG. 4 (b) shows the error. Signals are shown. The error signal has a profile proportional to the first derivative value of the absorption line, and the wavelength λ1 of the light source 1 and the absorption line in a region where the slope from the minus peak to the plus peak shown in FIG. Is proportional to the difference from the center wavelength λ1c. The control unit 101 and the wavelength converter 110 perform feedback control on the drive current of the light source 1 so that the error signal output from the error signal calculation unit 9 becomes zero, and the wavelength λ1 of the light source 1 is the center of the absorption line. Stabilization control is performed to the wavelength λ1c.

  Next, a case where the stabilization wavelength of the light source 1 is changed to a second stabilization wavelength λ2 different from the first stabilization wavelength λ1 will be described. In this case, first, the wavelength converter 110 cancels the stabilization control to the first stabilization wavelength λ1, and the driving element, the operating temperature, and the initial wavelength are substantially matched with the center wavelength λ2c of the second wavelength reference. The initial drive current is reset and the light source 1 is started up with this value. Also at this time, the driving element, the operating temperature, and the initial driving current are determined based on the wavelength temperature characteristic and the wavelength current characteristic of each driving element in the light source 1 measured in advance. When the center wavelength λ2c of the second wavelength reference is close to the center wavelength λ1c of the first wavelength reference, the wavelength converter 110 does not reset the driving element, and the operating temperature and the driving current are not reset. Only resetting may be performed. Hereinafter, the wavelength-stabilized light source 100 performs the stabilization control on the second wavelength reference peak as in the case of the first stabilized wavelength λ1. However, parameters such as the feedback gain of the control unit 101 may be changed for each wavelength reference.

  As described above, the wavelength-stabilized light source 100 is suitable for a high-accuracy wavelength reference that uses a wavelength-tunable DFB laser module in the entire C band as the light source 1 and covers the entire C band in the wavelength discriminator 6. A gas cell 60 having an absorption line group is used. That is, the wavelength-stabilized light source 100 can cover a band that cannot be covered by the conventional wavelength-stabilized light source. In addition, the conventional wavelength stabilized light source has a complicated overall configuration, such as using a plurality of gas cells in order to widen the band to be covered, or a plurality of control systems when using a plurality of etalon. However, with the wavelength-stabilized light source 100, the configuration itself can be simplified.

  As described above, according to the present embodiment, it is possible to provide a light source device that can be stabilized in a wide wavelength band with high accuracy with a simple configuration.

(Second Embodiment)
Next, a light source device according to a second embodiment of the invention will be described. In 1st Embodiment, the case where the wavelength stabilization light source 100 stabilized the wavelength of the light from the one light source 1 was illustrated. On the other hand, the light source device according to the present embodiment is characterized in that the wavelengths of a plurality of lights from a plurality of light sources are simultaneously stabilized. FIG. 5 is a schematic diagram illustrating a configuration of a wavelength-stabilized light source 200 as a light source device according to the present embodiment. Compared with the wavelength stabilized light source 100 according to the first embodiment, the wavelength stabilized light source 200 includes two light sources, a photodetector, an error signal calculation unit, and a wavelength converter, and further includes a wavelength discriminator 6. And a spectral filter 7 for branching the light from the light into a plurality. Hereinafter, as an example of the configuration of the wavelength-stabilized light source 200, it is assumed that two original light sources to be stabilized are included, and differences from the configuration of the wavelength-stabilized light source 100 according to the first embodiment will be described.

  The 1st light source 11 and the 2nd light source 12 can each be set as the structure similar to the light source 1 in 1st Embodiment. Hereinafter, the stabilization wavelength of the first light source 11 is assumed to be the wavelength λ1, and the stabilization wavelength of the second light source 12 is assumed to be the wavelength λ2. In this case, the optical demultiplexer 2 once splits the two lights emitted from the two light sources 11 and 12 into two paths after being coaxial. The branch destination is the same as in the first embodiment. Here, the transmission destination of the modulation signal generator 4 is three in total, that is, the first error signal calculation unit 91 and the second error signal calculation unit 92 in addition to the optical modulator 3.

Here, the wavelength discriminator 6 converts the frequencies of the first light source 11 and the second light source 12 modulated by the optical modulator 3 into intensity changes corresponding to the absorption spectrum. In the first embodiment, the gas cell 60 encapsulates two types of hydrogen cyanide gas isotopes, but in this embodiment, two types of molecules, ¹² C ₂ H ₂ and ¹³ C ₂ H ₂ , are used. Encapsulates seeds (acetylene gas isotopes). More specifically, the gas cell 60 may be a quartz glass tube having a length of 100 mm, in which ¹² C ₂ H ₂ is filled with 2.5 Torr and ¹³ C ₂ H ₂ is filled with 7.5 Torr. If the mirrors 61 and 62 are installed similarly to the first embodiment, according to this configuration, the wavelength discriminator 6 functions as a wavelength discriminator equivalent to the gas cell 60 having a cell length of 500 mm. Note that the cell length is not limited to only 500 mm, and if it is 500 mm or more, it is optimal in the present embodiment.

FIG. 6 is a graph showing an absorption spectrum of the wavelength discriminator 6 in the present embodiment. In FIG. 6, with respect to the absorption rate (calculated value) on the horizontal axis, the dotted line indicates the absorption line of ¹² C ₂ H ₂ and the solid line indicates the absorption line of ¹³ C ₂ H ₂ . ^Since the pressure of ¹³ C ₂ H ₂ is higher than that of ¹² C ₂ H ₂ , the wavelength discriminator 6 increases the absorption rate of the entire absorption band.

FIG. 7 is a graph showing the characteristics of the wavelength discriminator 6 in the present embodiment. Note that the way of viewing FIG. 7 (various definitions and the like) is the same as FIG. 3 in the first embodiment. 6 and 7, first, the performance coefficient of the absorption line at the bottom of the ¹³ C ₂ H ₂ absorption band near 1550 nm in FIG. 6 is the weak series at a pressure of 7.5 Torr in FIG. Corresponds to a value of approximately 0.5. On the other hand, the performance coefficient of the strong absorption line of ¹³ C ₂ H _{2 in} the band from 151.67 nm to 1521.56 nm (R band) in FIG. 6 is the Strong series at a pressure of 7.5 Torr in FIG. Corresponds to a value of approximately 0.1. The same applies to the band from 1528.59 nm to 1532.21 nm (P band). Therefore, this band cannot be used as a highly accurate wavelength reference. On the other hand, as shown in FIG. 6, there is an overlap in the absorption band of ¹³ C ₂ H ₂ and ¹² C ₂ H ₂ in the 1.5 μm band, and the band of strong absorption line of ¹³ C ₂ H ₂ includes ¹² C ₂ H ₂ strong absorption lines or absorption lines of moderate exists. The performance coefficients of these absorption lines of ¹² C ₂ H ₂ correspond to the values of the Strong series and the Middle series at a pressure of 2.5 Torr in FIG. 7 and are 0.78 and 0.93, respectively. Therefore, the ¹² C ₂ H ₂ absorption line can be substituted for the wavelength reference of the band of the strong absorption line of ¹³ C ₂ H ₂ here. Here, (Table 2) shows absorptance of typical absorption lines of the wavelength discriminator 6 in the present embodiment.

In this embodiment, the partial pressure of ¹³ C ₂ H ₂ is increased up to 6 times (maximum 7.5 Torr or more) of the optimum pressure 1.3 Torr in the absorption line having a strong absorption band peak (absorption line numbers: R8, P8). To increase the absorption rate to 98% or more. Thereby, the absorption rate of the absorption band skirt (absorption line number: P28) can be increased to 26.3% as shown in (Table 2). Similarly, in the wavelength discriminator 6, the absorption is 21% or more (corresponding to the absorption of a weak absorption line that can be used as a highly accurate wavelength reference with a performance coefficient of 0.5 or more shown in FIG. 7). The bandwidth of the line is from 1514.77 nm to 1550.18 nm. Therefore, the wavelength discriminator 6 can provide a highly accurate wavelength reference in a wide band including a part of the S band and the C band.

  FIG. 8 is a graph showing the spectral characteristics of the spectral filter 7. As shown in FIG. 8A, the spectral filter 7 is deposited with a dielectric multilayer film having a spectral characteristic of transmitting light having a wavelength λ1 and reflecting light having a wavelength λ2 as shown in FIG. 8B. High pass filter. The spectral filter 7 may be a band pass filter that selectively reflects a wavelength in the vicinity of the wavelength λ2. Of the light split by the spectral filter 7, the light with the wavelength λ 1 is guided to the first photodetector 81, and the light with the wavelength λ 2 is guided to the second photodetector 82. The first error signal calculation unit 91 is proportional to the difference between the wavelength λ1 and the center wavelength λ1c of the first light source 11 based on the reference signal from the modulation signal generator 4 and the output signal from the first photodetector 81. Output voltage signal. Similarly, the second error signal calculation unit 92 calculates the wavelength λ2 and the center wavelength λ2c of the second light source 12 based on the reference signal from the modulation signal generator 4 and the output signal from the second photodetector 82. Outputs a voltage signal proportional to the difference. In this case, the control unit 101 has two channels for the two light sources 11 and 12 having the calculation function required in the first embodiment. The first wavelength converter 111 arbitrarily selects and sets the driving element in the first light source 11 and its driving current and operating temperature, while the second wavelength converter 112 is in the second light source 12. These drive elements, and their drive current and operating temperature are arbitrarily selected and set. Note that the wavelength stabilized light source 200 can increase the number of corresponding wavelengths by increasing the number of stabilized original light sources, spectral filters, photodetectors, and error signal calculation units.

  According to the present embodiment, the same operations and effects as those of the first embodiment can be achieved, and even if there are a plurality of light sources (stabilized original light sources), the light modulator and the wavelength discriminator can be shared. The entire wavelength-stabilized light source can have a simple configuration. Moreover, since the absorption line intensity | strength of the acetylene used for the gas cell 60 in this embodiment is strong with respect to the hydrogen cyanide used for the gas cell 60 in 1st Embodiment, especially the wavelength discriminator 6 in this embodiment is 1st implementation. It can be smaller than in form. The wavelength-stabilized light source 200 in this embodiment can be particularly effective as a wavelength-stabilized light source for a multi-wavelength interferometer in which, for example, the selectivity and stability of the oscillation wavelength are important.

In each of the above embodiments, hydrogen cyanide or acetylene isotope is used as the standard substance sealed in the gas cell 60. However, in the present invention, not only isotopes but also two or more molecular species selected from a group of hydrogen cyanide isotopes including hydrogen cyanide (a group of acetylene isotopes including acetylene) may be used. Further, as the standard substance, for example, carbon monoxide proposed by NIST as SRM2514 and SRM2515 can also be used. In addition, M. Lackner, M. Schwarzott, and F. Winter, "CO and CO2 spectroscopy
using a 60nm broadband tunable MEMS-VCSEL at 〜1.55μm, Maximilian Lackner, Michael Schwarzott, Franz Winter ",
Carbon dioxide and the like described in Optics Letters, Vol. 31, No. 21, pp. 3170-3172 (2006) can also be used.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 Light source 6 Wavelength discriminator 8 Photo detector 9 Error signal calculating part 60 Gas cell 100 Wavelength stabilization light source 101 Control part

Claims (5)

A light source device that stabilizes the wavelength of light emitted from a light source,
A wavelength discriminator for discriminating the wavelength of the light, including a sealed container enclosing the standard material through which the light is transmitted;
A photodetector for detecting the light discriminated by the wavelength discriminator;
An error signal calculation unit that obtains an error signal using a detection signal from the photodetector;
A control unit that controls the wavelength of the light source based on the error signal from the error signal calculation unit;
The reference material includes two or more molecular species;
At least two of the molecular species have a region where an absorption band that is an absorption line group of the molecular species overlaps,
In the region where the absorption band overlaps, the absorption rate of the absorption line at the peak of the absorption band of at least one molecular species is 96% or more.
A light source device characterized by that.   2. The light source device according to claim 1, wherein the standard substance is two or more molecular species selected from the group of molecular species of hydrogen cyanide, acetylene, carbon monoxide, and carbon dioxide. The reference material is two or more molecular species selected from the group of hydrogen cyanide and hydrogen cyanide isotope,
The effective distance that the light passes through the sealed container is 1000 mm or more,
The maximum sealing pressure of at least one molecular species of the standard substance in the sealed container is 13.6 Torr or more;
The light source device according to claim 2. The reference material is two or more molecular species selected from the group of acetylene and acetylene isotopes;
The effective distance that the light passes through the sealed container is 500 mm or more,
The maximum sealing pressure of at least one molecular species of the standard substance in the sealed container is 7.5 Torr or more;
The light source device according to claim 2. The light source device according to claim 1, wherein the light source is a wavelength tunable laser light source.

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