JPH0672268U - External optical resonator device - Google Patents

Abstract

(57) [Abstract] [Objective] To realize an external optical resonator device in which the coupling efficiency between the laser light source and the resonator is enhanced. [Configuration] The output light of the laser light source is injected into the external resonator,
In the external optical resonator device utilizing the optical power generated inside the resonator, a mode matching lens for condensing the output light of the laser light source into the external resonator is used to cancel the astigmatism of the laser light source. It is characterized in that it is arranged at an angle with respect to the optical axis.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to highly efficient coupling of laser light to an external resonator.

[0002]

[Prior art]

 There is an application in which a large amount of power generated inside the external resonator is used by injecting laser light into the external resonator, such as wavelength conversion in the external resonator. In such applications, the generated power depends on how the mode of the laser light source matches the mode of the external cavity. To do this, in addition to the longitudinal mode such as wavelength, the spot diameter, position, wavefront, and amplitude distribution (deviation from Gauss) must be matched by the laser light source and the external resonator.

However, since the emission point of the laser light source is slightly different in the x direction and the y direction, simply arranging a mode-matching lens for condensing light on the optical path results in the same position due to astigmatism. Since the beam waist cannot be created, that is, the beam waist of the external cavity cannot be matched, the coupling efficiency between the laser light source and the external cavity was low.

[0004]

[Problems to be solved by the device]

 The present invention has been made in view of the above-mentioned problems of the prior art. The astigmatism of the laser light source is canceled by the astigmatism of the mode match lens, and the coupling efficiency between the laser light source and the external resonator is improved. The object is to provide an optical resonator device.

[0005]

[Means for Solving the Problems]

 The configuration of the present invention for solving the above-mentioned problems is an external optical resonator device that injects the output light of a laser light source into an external resonator and utilizes the optical power generated inside the external resonator. It is characterized in that a mode match lens for converging the output light on the external resonator is arranged so as to be inclined with respect to the optical axis so as to cancel astigmatism of the laser light source.

[0006]

[Action]

 According to the present invention, the mode-matching lens for condensing is used while being inclined with respect to the optical axis, so that the astigmatism of the mode-matching lens is generated and the astigmatism of the laser light source is canceled. ing.

[0007]

【Example】

 Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an external optical resonator device of the present invention. In FIG. 1, LD is a laser light source, CL is a collimator lens for making the laser light parallel light, and includes a prism for making the beam cross section circular. M₁, M ₂ Is a confocal mirror that constitutes an external resonator, and the beam waist (where the beam becomes the thinnest) of this external resonator is at point O. ML is an external resonator (M₁ , M₂) Is a mode match lens having a focal length f determined with respect to the beam waist O point of the external resonator (M₁, M₂) Is set at a distance l 1 ≈f (focal length) from the beam waist O point, and is tilted (θ) so as to eliminate the deviation of the beam waste due to the astigmatism of the laser light source LD. That is, by arranging the mode match lens ML in a tilted manner, astigmatism of the mode match lens ML is generated to cancel the astigmatism of the laser light source LD.

Here, as described in the above-mentioned prior art, since the emission point of the laser light source LD is different in the xz plane and the yz plane, as shown in FIG. 2, the external resonators (M ₁ , M ₂ ) The beam waists O ′ and O ″ of the laser light source LD cannot be matched with the beam waists O of the external resonators (M ₁ and M ₂ ), and the coupling efficiency was low.

In the present invention, as shown in FIG. 1, the mode match lens ML is arranged to be inclined. As a result, astigmatism occurs in the mode match lens ML, the astigmatism of the laser light source LD can be canceled, and the beam waste O of the external resonators (M ₁ , M ₂ ) can be matched. High coupling efficiency can be obtained. The focal lengths of the mode match lens ML depending on the inclination angle θ are as follows: f _{xz ≈f} · cos θ f _{yz ≈f} / cos θ.

[0010]

[Effect of device]

 As described above in detail with reference to the embodiments, according to the present invention, the coupling efficiency between the laser light source and the external resonator can be increased without increasing the number of parts.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an external optical resonator device of the present invention.

FIG. 2 is a conventional example.

[Explanation of symbols]

LD laser light source CL collimator lens ML mode match lens M ₁ , M ₂ external resonator

Claims (1)

[Scope of utility model registration request] 1. An external optical resonator device for injecting output light of a laser light source into an external resonator and utilizing optical power generated inside the external resonator, wherein the output light of the laser light source is supplied to the external resonator. An external optical resonator device, wherein a mode-matching lens for condensing light is arranged so as to be inclined with respect to an optical axis so as to cancel astigmatism of the laser light source.