CN113540975A

CN113540975A - Grating pitching angle centering fine-adjustment device

Info

Publication number: CN113540975A
Application number: CN202110588494.XA
Authority: CN
Inventors: 郭裕聪; 朱兴邦
Original assignee: CETC 41 Institute
Current assignee: CETC 41 Institute
Priority date: 2021-05-28
Filing date: 2021-05-28
Publication date: 2021-10-22
Anticipated expiration: 2041-05-28
Also published as: CN113540975B

Abstract

The invention belongs to the technical field of semiconductors, and relates to a grating pitch angle centering fine adjustment device in an external cavity type tunable laser source. A grating pitch angle centering fine adjustment device comprises an adjusting bracket and piezoelectric ceramics; the piezoelectric ceramics are vertically arranged in the adjusting bracket; a flexible hinge structure is arranged between the upper part and the lower part of the adjusting bracket; the rotation center of the flexible hinge structure is superposed with the grating plane and the light path plane. According to the device, the grating plane, the light path plane and the rotation center of the flexible hinge are overlapped, so that the position of the grating in the light path is not changed and the length of the external cavity light path is not changed when the pitch angle of the grating is adjusted. The grating and the adjusting bracket do not need to be adjusted before being glued, and only the pitch angle of the grating is adjusted by piezoelectric ceramics after the device is arranged on an external cavity; the requirement on operators is low, and the adjustment can be completed only by observing the external cavity output index parameters through an external measuring instrument and determining the proper piezoelectric ceramic voltage.

Description

Grating pitching angle centering fine-adjustment device

Technical Field

The invention belongs to the technical field of semiconductors, and relates to a grating pitch angle centering fine adjustment device in an external cavity type tunable laser source.

Background

With the development of science and technology, the requirements on semiconductor laser light sources are higher and higher, and the laser is required to have narrow line width and continuously adjustable wavelength in a larger range. The external cavity type tunable laser source provides a possible approach for realizing a large continuous tuning range. The principle is to continuously change the wavelength of the laser by continuously changing the cavity length of the external cavity. However, in general, mode hopping occurs during wavelength tuning, which limits the continuous tunable range of the wavelength. How to obtain a large range of continuous tunability is one of the core problems of external cavity design.

The external cavity type tunable laser light source is required to have a large wavelength range without mode hopping, and the perpendicularity between the rotation axis of the rotating device and the plane of the optical path is required to be less than 0.01 degrees, as shown in fig. 1, so that the requirements on the processing and assembling precision of optical path parts are extremely high.

The external cavity type tunable laser light source mainly comprises a semiconductor laser, a grating and a reflector. The reflector is a rotating device, and under the condition that the rotation center is determined, the perpendicularity between the light path plane and the rotation center can be reduced by adjusting the pitching angle of the grating, so that the influence caused by part processing errors is reduced.

At present, the existing installation and adjustment means of the grating mainly comprises the steps of clamping and adjusting the grating by using a six-dimensional adjusting table, and bonding the grating with a grating base after the adjustment is finished. The six-dimensional adjusting platform comprises a three-dimensional adjusting platform, a two-dimensional deflection adjusting platform and a rotating platform, the three platforms are stacked and installed, and the rotating center of pitching angle adjustment is not coincident with the grating surface. After the grating pitch angle is adjusted, the change of the optical path cavity length caused by the adjustment of the pitch angle can be eliminated by adjusting variables such as dx, dy and the like, as shown in fig. 2.

The existing installation and adjustment mode mainly has the following defects:

1) the adjusting device is costly. Because the adjustment precision is high, the requirement on the movement precision of the six-dimensional adjusting table is high. The adjustment of part of sensitive dimensions can meet the requirement of adjustment precision only by using a high-precision differential adjusting rod to be matched with a piezoelectric actuator;

2) the regulation efficiency is low. During adjustment, the six dimensions need to be roughly adjusted, and after the external cavity light path vibrates, the grating is finely adjusted according to the reading of the instrument. After the pitch angle of the grating is adjusted, other multiple dimensions need to be adjusted, the efficiency is low, and the adjusting process is complicated;

3) the grating glue joint causes the grating position to change. At present, UV glue is selected as a cementing material, and the position of the grating can be changed due to the generated shrinkage stress in the ultraviolet curing process;

4) the adjustment process is complicated, the requirement on adjustment operators is high, and the method is not suitable for mass production of the outer cavity.

Disclosure of Invention

The invention aims to provide a device for finely adjusting the pitching angle of a grating in an external cavity type tunable laser source, which has a simple structure and is convenient to adjust the angle.

In order to achieve the purpose, the invention adopts the technical means that: a grating pitch angle centering fine adjustment device comprises an adjusting bracket and piezoelectric ceramics; the piezoelectric ceramics are vertically arranged in the adjusting bracket; a flexible hinge structure is arranged between the upper part and the lower part of the adjusting bracket; the rotation center of the flexible hinge structure is superposed with the grating plane and the light path plane.

As a preferable mode of the present invention, a vertically arranged tension spring is provided in the adjusting bracket.

Further preferably, a grating fixing window is arranged on the front side surface of the adjusting bracket.

Further preferably, strain gauges are arranged on two sides of the grating fixing window.

Further preferably, a grating positioning panel is arranged in the grating fixing window.

Further preferably, the upper edge of the grating fixing window is provided with a periodic arc groove, and the periodic arc groove is connected with the grating through gluing.

Compared with the prior art, the invention has the following beneficial effects:

(1) the cost is low: compared with the prior art, the device has the advantages that the material cost is reduced by more than 90%;

(2) the regulation efficiency is high: the grating and the adjusting bracket do not need to be adjusted before being glued, and only the pitch angle of the grating is adjusted by piezoelectric ceramics after the device is arranged on an external cavity;

(3) after the installation is finished, the grating position change caused by the curing stress of the cementing material can not be generated;

(4) the requirement on operators is low, and the adjustment can be completed only by observing the external cavity output index parameter and the strain gauge parameter through an external measuring instrument and determining the proper piezoelectric ceramic voltage.

Drawings

FIG. 1 is a schematic diagram of a tunable laser source;

FIG. 2 is a schematic diagram of a prior art grating pitch angle adjustment;

FIG. 3 is a front view of a fine tuning device for centering a pitch angle of a grating according to an embodiment of the present invention;

FIG. 4 is a rear view of a fine tuning device for centering the pitch angle of a grating according to an embodiment of the present invention;

FIG. 5 is a schematic view of the attachment of a grating to the device of the present invention;

FIG. 6 is a schematic diagram showing the relative positions of the rotation center of the adjusting bracket, the grating plane and the light path plane.

Detailed Description

In order to facilitate an understanding of the invention, the invention is described in more detail below with reference to the accompanying drawings and specific examples. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

The fine tuning device for the pitch angle centering of the grating provided by the embodiment has a structure as shown in fig. 3 and 4, and mainly comprises an adjusting bracket 1, piezoelectric ceramics 2 and a tension spring 3.

Wherein, the rear portion of adjusting support 1 is equipped with recess 4, and piezoceramics 2 sets up in recess 4. And tension springs 3 which are arranged up and down are respectively arranged on two sides of the piezoelectric ceramics.

The adjusting support 1 is provided with a flexible hinge structure 7 in the horizontal direction, the flexible hinge structure 7 divides the adjusting support 1 into an upper part and a lower part which are connected, and when the piezoelectric ceramic 2 deforms, the flexible hinge structure 7 is driven to deform to a certain extent. The flexible hinge structure 7 is a rotary motion structure, and the center of the rotary circle can be considered to be fixed when the distance of the rotary motion structure is small.

The front side surface of the upper part of the adjusting bracket 1 is provided with a grating fixing window 6.

As shown in fig. 3, the upper edge of the grating fixing window 6 is provided with a continuous periodic circular arc groove 8. The periodic circular arc groove 8 is used for fixing the grating 10. And gluing the connecting plane between the adjacent 2 arc grooves to glue and fix the grating, wherein the arc grooves are not glued and connected with the grating. The gluing method has higher reliability than continuous gluing in one plane. A positioning panel 14 is arranged in the grating fixing window 6, and the grating can be accurately positioned through the positioning panel, so that the plane of the grating is coincident with the rotation center of the flexible hinge structure 7.

Strain gauges 9 are fixed to the left and right sides of the grating fixing window 6.

The grating pitch angle centering fine-tuning device of the embodiment has the following working principle:

as shown in fig. 5, the upper half of the grating 10 is positioned and glued to the upper edge of the grating fixing window 6 on the adjusting bracket 1, and the lower half of the grating is suspended in the grating fixing window 6. Certain voltage is applied to the piezoelectric ceramic 2, the piezoelectric ceramic 2 deforms, so that the flexible hinge structure 7 is driven to deform elastically, the grating 10 is driven to rotate by taking the rotation center of the flexible hinge structure as an axis, and fine adjustment of the pitch angle of the grating is achieved. Meanwhile, the pitch angle of the grating 10 is fed back in real time through the strain gauge 9.

The tension spring 3 is used for providing elastic force or retraction force when the piezoelectric ceramic 2 deforms, and is matched with the piezoelectric ceramic to finely adjust the pitch angle of the grating.

As shown in fig. 6, in the fine tuning device for centering the pitch angle of the grating provided by the present invention, since the rotation center 11 of the adjusting bracket 1 is overlapped with the grating plane 12 and the optical path plane 13, the position of the grating in the optical path is not changed and the length of the external cavity optical path is not changed when the grating 10 is adjusted in the pitch angle.

Claims

1. The utility model provides a grating every single move angle centering micromatic setting which characterized in that: comprises an adjusting bracket and piezoelectric ceramics; the piezoelectric ceramics are vertically arranged in the adjusting bracket; a flexible hinge structure is arranged between the upper part and the lower part of the adjusting bracket; the rotation center of the flexible hinge structure is superposed with the grating plane and the light path plane.

2. The fine grating pitch angle centering adjustment device according to claim 1, wherein: and a vertically arranged tension spring is arranged in the adjusting bracket.

3. The grating pitch angle centering vernier device as claimed in claim 1 or 2, wherein: and the front side surface of the adjusting bracket is provided with a grating fixing window.

4. The fine grating pitch angle centering adjustment device according to claim 3, wherein: and strain gauges are arranged on two sides of the grating fixing window.

5. The fine grating pitch angle centering adjustment device according to claim 3, wherein: and a grating positioning panel is arranged in the grating fixing window.

6. The fine grating pitch angle centering adjustment device according to claim 3, wherein: and the upper edge of the grating fixing window is provided with a periodic arc groove, and the periodic arc groove is connected with the grating through gluing.