CN112271550A

CN112271550A - Wavelength-locked semiconductor laser

Info

Publication number: CN112271550A
Application number: CN202011125130.XA
Authority: CN
Inventors: 陈晓华; 郭渭荣; 王宝华
Original assignee: Beijing Kaiplin Optoelectronics Technology Co ltd
Current assignee: Beijing Kaiplin Optoelectronics Technology Co ltd
Priority date: 2020-10-20
Filing date: 2020-10-20
Publication date: 2021-01-26

Abstract

The invention discloses a wavelength-locked semiconductor laser, which comprises a semiconductor laser light source, a first prism, a spatial filter and a second prism, wherein the semiconductor laser light source, the first prism, the spatial filter and the second prism are sequentially arranged; after the light beam emitted by the light source of the semiconductor laser passes through the first prism, different wavelengths are transmitted along different angles, the light within a preset wavelength range is reserved after passing through the spatial filter, and the light within the preset wavelength range is transmitted along the same angle after passing through the second prism. According to the technical scheme, the combination of the spatial filter and the prism pair is additionally arranged in the semiconductor laser, so that the wavelength range output by the semiconductor laser is locked in a range from several nm to dozens of nm.

Description

Wavelength-locked semiconductor laser

Technical Field

The invention belongs to the technical field of semiconductor laser manufacturing, and particularly relates to a wavelength-locked semiconductor laser.

Background

The single tube semiconductor laser is the most practical and important laser, and has small volume, long service life, simple pumping with injected current, and operating voltage and current compatible with integrated circuit, so that it may be integrated monolithically and may be current modulated directly at GHz frequency to obtain high speed modulated laser output. Due to the advantages, the single tube of the semiconductor laser is widely applied to aspects of laser communication, optical storage, optical gyros, laser printing, distance measurement, radar and the like.

In some applications, such as gas detection, solid-state laser pumping, it is desirable to lock the wavelength range of the semiconductor laser output to a range from a few nanometers to tens of nanometers wide. The grating is a commonly used element for locking the output wavelength of a semiconductor laser, but the range of the grating locking wavelength is below 1nm, and the grating is not suitable for the locking range from several nm to dozens of nm. Therefore, a new technical solution is needed to solve the above problems.

Disclosure of Invention

In view of the above, the present invention discloses a wavelength-locked semiconductor laser to overcome or at least partially solve the above problems.

In order to achieve the purpose, the invention adopts the following technical scheme:

a wavelength-locked semiconductor laser is characterized by comprising a semiconductor laser light source, a first prism, a spatial filter and a second prism, wherein the semiconductor laser light source, the first prism, the spatial filter and the second prism are sequentially arranged;

after the light beam emitted by the light source of the semiconductor laser passes through the first prism, different wavelengths are transmitted along different angles, the light within a preset wavelength range is reserved after passing through the spatial filter, and the light within the preset wavelength range is transmitted along the same angle after passing through the second prism.

Optionally, the spatial filter is a pinhole filter.

Optionally, the pinhole filter includes a first lens, a pinhole, and a second lens, and the above devices are arranged in sequence.

Optionally, a fast axis collimating lens is further disposed between the semiconductor laser light source and the first prism.

Optionally, an external cavity mirror is further disposed behind the second prism, and the light beam processed by the second prism is reflected by the external cavity mirror and returns to the light source of the semiconductor laser, so as to realize output wavelength locking.

Optionally, the first prism and the second prism are made of materials with abbe numbers smaller than 50.

Optionally, the first prism and the second prism are made of k6-k10 glass or quartz.

Optionally, the difference between the upper and lower limits of the preset wavelength range is 5-60nm, wherein the upper limit wavelength range is 700-960 nm.

Optionally, the refractive index of the first prism and the second prism is 1.4-1.6.

Optionally, the pinhole has a diameter of 0.08-0.2 mm.

The invention has the advantages and beneficial effects that:

according to the technical scheme, the combination of the spatial filter and the prism pair is arranged, the wavelength range output by the semiconductor laser is locked in the range from several nm to dozens of nm, the structure is simple, the realization is convenient, and remarkable beneficial effects are obtained.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a schematic diagram of a wavelength-locked semiconductor laser according to one embodiment of the present invention;

FIG. 2(a) is a schematic diagram of the optical path of the lower limit wavelength in the light beam;

FIG. 2(b) is a schematic diagram of the path of a center wavelength light beam;

FIG. 2(c) is a schematic diagram of the upper limit wavelength path in a beam;

FIG. 3 is a schematic diagram of the refraction angle of a prism according to an embodiment of the present invention.

In the figure: the laser device comprises a light beam 1, a semiconductor laser light source (single tube) 2, a fast axis collimating lens 3, a prism pair 4, a prism 1 at 4.1, a prism 2 at 4.2, a filter 5, a first lens 5.1, a second lens 5.2, a pinhole 5.3 and an external cavity mirror 6.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail and fully with reference to the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The technical solutions provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

Referring to the schematic structural diagram of the wavelength-locked semiconductor laser shown in fig. 1, the semiconductor laser includes a semiconductor laser light source 2, a first prism 4.1, a spatial filter 5, and a second prism 4.2, which are arranged in sequence.

After the light beam emitted by the semiconductor laser light source 2 passes through the first prism 4.1, different wavelengths are transmitted along different angles, the light within the preset wavelength range is reserved after passing through the spatial filter 5, and the light within the preset wavelength range is transmitted along the same angle after passing through the second prism 4.2.

The semiconductor laser light source 2 is preferably a single semiconductor laser tube, the spatial filter 5 is preferably a pinhole filter, and the prism is preferably a high-dispersion material.

The semiconductor laser is combined with the spatial filter through the prism pair, so that the wavelength of the light beam passing through the combination is limited within the range of a few nm to dozens of nm in width, the structure is simple, the realization is convenient, and remarkable beneficial effects are obtained.

Preferably, referring to fig. 1, the pinhole filter comprises a first lens 5.1, a pinhole 5.3 and a second lens 5.2, and the above devices are arranged in sequence. Wherein the diameter of the pinhole 5.3 is 0.08-0.2 mm.

A fast axis collimating lens 3 is further arranged between the semiconductor laser light source 2 and the first prism 4.1, and is used for realizing the collimation of the light beam in the fast axis direction and compressing the divergence angle of the light beam in the fast axis direction.

And an external cavity mirror 6 is arranged behind the second prism 4.2, and the light beam is reflected by the external cavity mirror 6 after being processed by the second prism 4.2 and returns to the semiconductor laser light source 2, so that the output wavelength locking is realized.

In order to secure the prism dispersion effect, the prism is made of a material having high dispersion, and preferably, the first prism and the second prism are made of a material having an abbe number of less than 50. The dispersion coefficient is expressed by abbe number, and the larger the abbe number is, the smaller the dispersion is, whereas the smaller the abbe number is, the larger the dispersion is.

Specifically, the first prism and the second prism may use k6-k10 glass or quartz. Glasses having similar chemical compositions and optical properties are also distributed at adjacent positions on the abbe diagram. The abbe diagram has a group of straight lines and curves, and is divided into a plurality of areas to classify the optical glass; for example, crown glasses K7, K10 are in K zone.

In this embodiment, the prism may be made of glass K6-K10 to obtain better dispersion effect, or made of quartz, and the refractive index of the first prism and the second prism is preferably 1.4-1.6.

In addition, the difference value of the upper and lower limit wavelengths of the preset wavelength range of the filtered light beam is 5-60nm, wherein the upper limit wavelength range is 700-960 nm.

The above ranges of device materials, parameters and values are only preferred embodiments and are not intended to limit the devices, and other materials and values are within the scope of the present invention.

The working process of the semiconductor laser is as follows: with reference to the schematic propagation diagram of the optical path with the upper and lower limit wavelengths shown in fig. 2, after the light beam is emitted from the single tube 2 of the semiconductor laser, and is collimated by the fast axis collimating lens, the light beam corresponding to different wavelengths and having different propagation directions is focused on different positions on the plane where the pinhole 5.3 is located through the first lens 5.1 of the pinhole filter 5. Where the lower wavelength beam 1.1 is focused at the lower edge of the pinhole 5.3, the central wavelength beam 1.2 passes through the centre of the pinhole 5.3 and the upper wavelength beam 1.3 is focused at the upper edge of the pinhole 5.3. Light beams having wavelengths between the lower and upper limit wavelengths can pass through, while light beams having wavelengths greater than or less than the lower limit wavelength are blocked.

After the filtered beam 1 has passed the second lens 5.2 of the pinhole filter 5, the different wavelengths of the light in the specified wavelength range propagate along different angles.

After the filtered beam 1 has passed through the second prism 4.2 of the prism pair 4, the beams 1 propagating at different angles recombine to propagate along the same angle.

And then, after being reflected by the external cavity mirror 6, the light beam 1 returns to the single semiconductor laser tube 2 in the original path, thereby realizing output wavelength locking.

Two specific examples are given below:

example 1

The apex angle of the prism 4 is selected to be 40 degrees, the material is K9, the lower limit wavelength is 905nm, the central wavelength is 915nm, and the upper limit wavelength is 925 nm. The focal length of the pinhole filter lens is 119mm, and the pinhole diameter Wfilter is 0.1 mm.

The refractive indices of the prism for the 3 wavelengths are 1.50892, 1.50876, 1.5086, respectively.

As shown in fig. 3, the refraction angles can be calculated as: θ 2 ═ 35.8859 °, θ 1 ═ 0.0241 °, and θ 3 ═ 0.0242.

The lower limit wavelength is focused 0.050262mm below the center of the pinhole just at the lower edge of the pinhole; the central wavelength passes through the center of the pinhole after being focused; the upper wavelength was focused 0.0500543mm above the center of the pinhole, just at the upper edge of the pinhole.

Wavelengths between 905nm and 925nm can pass through the pinhole filter 5 so that the wavelength of the single semiconductor laser tube 2 is locked in this range.

Example 2

The vertex angle of the prism is selected to be 40 degrees, the material is quartz, the lower limit wavelength is 905nm, the central wavelength is 915nm, and the upper limit wavelength is 925 nm. The focal length of the lens of the pinhole filter 5 is 200mm, and the diameter Wfilter of the pinhole is 0.1 mm.

The refractive indices of the prism for the 3 wavelengths are 1.45169, 1.45155, 1.45141, respectively.

As shown in fig. 3, the refraction angle θ 2 ═ 28.9135 °, θ 1 ═ 0.0143 °, and θ 3 ═ 0.0143 ° can be calculated.

The lower limit wavelength is focused 0.0499mm below the center of the pinhole just at the lower edge of the pinhole; the central wavelength passes through the center of the pinhole after being focused; the upper wavelength was focused 0.0499mm above the center of the pinhole, just at the upper edge of the pinhole.

Wavelengths between 905nm and 925nm can pass through the pinhole filter so that the wavelength of a single tube of the semiconductor laser is locked in this range.

In summary, the embodiment realizes selection and locking of a wider wavelength range of a light beam through the pinhole filter and the prism, is superior to the wavelength range of the grating when wavelength locking is performed, has a simple structure, is convenient to realize, and obtains remarkable beneficial effects.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, extension, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A wavelength-locked semiconductor laser is characterized by comprising a semiconductor laser light source, a first prism, a spatial filter and a second prism, wherein the semiconductor laser light source, the first prism, the spatial filter and the second prism are sequentially arranged;

2. A semiconductor laser as claimed in claim 1 wherein the spatial filter is a pinhole filter.

3. A semiconductor laser as claimed in claim 2 wherein the pinhole filter comprises a first lens, a pinhole and a second lens, arranged in sequence.

4. A semiconductor laser as claimed in claim 3 wherein a fast axis collimating lens is also provided between the semiconductor laser light source and the first prism.

5. A semiconductor laser as claimed in any one of claims 1-4 wherein an external cavity mirror is disposed behind the second prism, and the light beam processed by the second prism is reflected by the external cavity mirror and returned to the semiconductor laser light source to realize output wavelength locking.

6. A semiconductor laser according to any of claims 1-4, characterized in that the first prism and the second prism are of a material with an Abbe number of less than 50.

7. The semiconductor laser according to any of claims 1-4, wherein the first prism and the second prism use k6-k10 glass or quartz.

8. The semiconductor laser according to any of claims 1-4, wherein the difference between the upper and lower limit wavelengths of the predetermined wavelength range is 5-60nm, wherein the upper limit wavelength range is 700-960 nm.

9. The semiconductor laser according to any of claims 1-4, wherein the refractive indices of the first prism and the second prism are 1.4-1.6.

10. A semiconductor laser according to any of claims 3-4, characterized in that the diameter of the pinhole is 0.08-0.2 mm.