Polarization conversion device and optical module

Abstract

The invention relates to the technical field of optical modules, in particular to a polarization conversion device and an optical module.The polarization conversion device comprises an optical fiber array, a polarization splitting prism, a wave plate, a depolarization light combination prism and a converging lens which are sequentially arranged, light beams enter the polarization splitting prism from the optical fiber array, and parallel polarized light is transmitted to the wave plate through the polarization splitting prism; the polarized light is converted into a vertical polarization state through the wave plate, then enters the depolarization light-combining prism and enters the converging lens after passing through the depolarization light-combining prism, the vertical polarization light sequentially passes through the polarization splitting prism, the wave plate and the depolarization light-combining prism and then enters the converging lens, and the two beams of vertical polarization light entering the converging lens are focused through the converging lens and then output. According to the light converging device, the light converging function in the vertical polarization state is achieved, the total energy of the light in the parallel polarization state and the light in the vertical polarization state after light combination is very stable, the design is not prone to external interference, a polarization maintaining device high in cost does not need to be used in the design, the overall cost is effectively reduced, and large-scale deployment is better facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of optical modules, and in particular to a polarization conversion device and an optical module. Background Art

[0002] For special photonic chips, the external optical signal input is required to be in a vertical polarization state. In order to meet the requirements of vertically polarized converged light, the current input optical signal is accessed using polarization-maintaining fiber. The polarization-maintaining fiber is fixed by a bracket, and then the light beam is transmitted to the lens array. After passing through the lens array, the light beam converges. At this time, the polarization state of the light is consistent with the polarization-maintaining fiber, which meets the requirements of the back-end chip. The converged light is then coupled to the photonic chip. This method uses polarization-maintaining fiber, and the cost of polarization-maintaining fiber is very high. If the optical device is deployed on a large scale, the cost will be very high.

[0003] Therefore, it is very important for those skilled in the art to design a polarization conversion device and an optical module that can meet the requirements of vertically polarized converged light and have low cost. Summary of the invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a low-cost polarization conversion device and an optical module that can meet the requirements of vertically polarized converged light, so as to solve the problem of high cost caused by using polarization-maintaining optical fiber in the prior art.

[0005] The present invention discloses a polarization conversion device, which comprises: an optical fiber array, a polarization beam splitter prism, a wave plate, a depolarization light combining prism and a converging lens which are arranged in sequence, wherein a light beam enters the polarization beam splitter prism from the optical fiber array, wherein parallel polarized light is transmitted to the wave plate through the polarization beam splitter prism, is converted into a vertical polarization state through the wave plate and then enters the depolarization light combining prism, and then enters the converging lens through the depolarization light combining prism, wherein vertical polarized light passes through the polarization beam splitter prism, the wave plate and the depolarization light combining prism in sequence and then enters the converging lens, and the two beams of vertical polarized light incident on the converging lens are focused by the converging lens and then output.

[0006] Optionally, one end of the wave plate is a half-wave plate, and the other end of the wave plate is a glass plate. The parallel polarized light is converted into vertical polarized light by the half-wave plate and then incident on the depolarized light combining prism. The vertical polarized light is transmitted through the glass plate and then incident on the depolarized light combining prism.

[0007] Optionally, the glass sheet and the half-wave plate have the same thickness.

[0008] Optionally, a polarization splitter film is disposed in the polarization splitter prism to transmit parallel polarized light and reflect vertical polarized light.

[0009] Optionally, a first high-reflection film is further provided in the polarization beam splitting prism, so as to reflect the vertically polarized light reflected by the polarization beam splitting film into the glass sheet.

[0010] Optionally, a second high-reflection film is provided in the depolarization light-combining prism to reflect incident vertically polarized light.

[0011] Optionally, a depolarizing beam splitting film is further provided in the depolarizing light combining prism, so as to semi-transmit and semi-reflect the vertically polarized light reflected by the second high-reflection film.

[0012] Optionally, the depolarizing light combining prism further includes an absorption film for absorbing the light beam transmitted or reflected by the depolarizing light splitting film.

[0013] Optionally, a collimating lens array is further included, and the collimating lens array is arranged between the optical fiber array and the polarization beam splitter prism for light beam collimation.

[0014] In order to solve the problems existing in the prior art, the present invention further provides an optical module, characterized in that it includes any polarization conversion device as described above, and also includes a photonic chip, and the photonic chip is arranged on the light output side of the polarization conversion device.

[0015] Compared with the prior art, the polarization conversion device provided by the embodiment of the present invention has the beneficial effect that: by designing a polarization conversion device, including an optical fiber array, a polarization beam splitter prism, a wave plate, a depolarization light combining prism and a converging lens arranged in sequence, a light beam enters the polarization beam splitter prism from the optical fiber array, wherein parallel polarized light is transmitted to the wave plate through the polarization beam splitter prism, is converted into a vertical polarization state through the wave plate and then enters the depolarization light combining prism, and then enters the converging lens after passing through the depolarization light combining prism, and the vertical polarized light is sequentially passed through the polarization beam splitter prism, the wave plate and the depolarization light combining prism and then enters the converging lens, the two beams of vertical polarized light incident on the converging lens are focused by the converging lens and then output, thereby realizing the function of converging light in a vertical polarization state, and the total energy of the parallel polarization state light and the vertical polarization state light after light combination is very stable, which is half of the initial energy, so that the design is not easily affected by external interference, and the design does not need to use expensive polarization-maintaining devices, effectively reduces the overall cost, and is more conducive to large-scale deployment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0017] Figure 1 is a three-dimensional schematic diagram of a polarization conversion device provided by an embodiment of the present invention;

[0018] Figure 2 is an exploded schematic diagram of a polarization conversion device provided by an embodiment of the present invention;

[0019] Figure 3 It is a three-dimensional schematic diagram of an optical module provided by an embodiment of the present invention.

[0020] The reference numerals in the figures are:

[0021] 100, optical fiber array; 200, polarization beam splitter prism; 300, wave plate; 400, depolarization beam combining prism; 500, converging lens; 600, collimating lens array; 700, photonic chip; 310, half-wave plate; 320, glass sheet; 210, polarization beam splitter film; 220, first high-reflection film; 410, second high-reflection film; 420, depolarization beam splitter film; 430, absorption film. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, the preferred embodiments of the present invention are described in detail.

[0023] like Figures 1 to 3 As shown, the present invention provides a specific embodiment of a polarization conversion device.

[0024] A polarization conversion device, referring to Figure 1 The polarization conversion device includes an optical fiber array 100, a polarization beam splitter prism 200, a wave plate 300, a depolarization light combining prism 400 and a converging lens 500. The polarization beam splitter prism 200 is arranged on the light exiting side of the optical fiber array 100, the wave plate 300 is arranged on the light exiting side of the polarization beam splitter prism 200, the depolarization light combining prism 400 is arranged on the light exiting side of the wave plate 300, the converging lens 500 is arranged on the light exiting side of the depolarization light combining prism 400, and the light exiting side of the converging lens 500 is used to connect an external photonic chip.

[0025] Among them, a light beam in a randomly polarized state is incident on the polarization beam splitter prism 200 through the optical fiber array 100, and the parallel polarized light enters the polarization beam splitter prism 200, and then is transmitted to the wave plate 300 through the polarization beam splitter prism 200, and then is converted into a vertical polarization state by the wave plate 300 and is incident on the depolarization light combining prism 400. After passing through the depolarization light combining prism 400, half of the energy of the light beam is absorbed, and the other half of the energy is incident on the converging lens 500. The vertically polarized light enters the polarization beam splitter prism 200, and then enters the wave plate 300 after multiple reflections by the polarization beam splitter prism 200, and then is transmitted to the depolarization light combining prism 400 through the wave plate 300. After passing through the depolarization light combining prism 400, half of the energy of the light beam is absorbed, and the other half of the energy is also incident on the converging lens 500. The two beams of vertically polarized light incident on the converging lens 500 are focused by the converging lens 500 to be transmitted to the photonic chip at the rear end.

[0026] A photonic chip is a microchip that uses the quanta of light to transmit and process information. It uses the fast propagation speed and low energy consumption characteristics of light to achieve higher data transmission rates and lower energy consumption. It can integrate various optical devices, such as optical waveguides, optical modulators, photodetectors, etc., to realize the processing and control of optical signals. It can also be used for optical computing, optical logic operations, analog computing, etc. It can also be used for quantum information processing to support the control, manipulation and transmission of quantum states. It can also be used for optical sensing applications, such as environmental parameter monitoring, biosensing, etc. The polarization conversion device is used in the optical module as the front end of the photonic chip and provides vertically polarized light signals for some photonic chips in need.

[0027] At present, in order to meet the requirements of photonic chips for vertically polarized converged light, polarization-maintaining optical fiber is usually used to access and output optical signals. That is, the polarization-maintaining optical fiber is fixed by a bracket, and then the light beam is transmitted to the lens array. The light beam converges after passing through the lens array. At this time, the polarization state of the light is consistent with the polarization-maintaining optical fiber, that is, the requirements of the back-end chip are met. Then, the converged light is coupled with the photonic chip. In this method, polarization-maintaining optical fiber is used, and the cost of polarization-maintaining optical fiber accounts for a very high proportion. If the optical device is deployed on a large scale, the cost will be very high.

[0028] In this embodiment, a polarization conversion device is designed, including an optical fiber array 100, a polarization beam splitter prism 200, a wave plate 300, a depolarization light combining prism 400 and a converging lens 500 arranged in sequence. The light beam enters the polarization beam splitter prism 200 from the optical fiber array 100, wherein the parallel polarized light is transmitted to the wave plate 300 through the polarization beam splitter prism 200, and is converted into a vertical polarization state by the wave plate 300 and then incident on the depolarization light combining prism 400, and then incident on the converging lens 500 after passing through the depolarization light combining prism 400, and the vertical polarized light After passing through the polarization splitter prism 200, the wave plate 300 and the depolarization light combining prism 400 in sequence, the two vertically polarized lights incident on the converging lens 500 are focused by the converging lens 500 and then output, thereby realizing the function of converging light in a vertical polarization state. Moreover, the total energy of the light in the parallel polarization state and the light in the vertical polarization state after light combination is very stable, which is half of the initial energy, making the design less susceptible to external interference. Moreover, the design does not require the use of expensive polarization-maintaining devices, thereby effectively reducing the overall cost and being more conducive to large-scale deployment.

[0029] In one embodiment, reference Figure 1 The polarization conversion device further includes a collimating lens array 600, which is disposed between the optical fiber array 100 and the polarization beam splitter prism 200, and is used to collimate the light beam input from the optical fiber array 100 to output collimated light.

[0030] In one embodiment, reference Figure 1and Figure 2 One end of the wave plate 300 is a half-wave plate 310, and the other end of the wave plate 300 is a glass plate 320, wherein a light beam in a randomly polarized state is incident from the optical fiber array 100 to the polarization beam splitter prism 200, and the parallel polarized light is transmitted to the half-wave plate 310 through the polarization beam splitter prism 200, and is converted into vertical polarized light by the half-wave plate 310 and then incident on the depolarization light combining prism 400, and the vertical polarized light is reflected multiple times by the polarization beam splitter prism 200 to the glass plate 320, and is transmitted through the glass plate 320 and then incident on the depolarization light combining prism 400; this design is used to compensate the light path in the structure, and the thickness of the glass plate 320 and the half-wave plate 310 are consistent to ensure that the light path at the front and rear ends is consistent.

[0031] In one embodiment, reference Figure 1 and Figure 2 The polarization splitter prism 200 is provided with a polarization splitter film 210 and a first high reflection film 220 . The polarization splitter film 210 is used to transmit parallel polarized light and reflect vertical polarized light. The first high reflection film 220 is used to reflect the vertical polarized light reflected by the polarization splitter film 210 into the glass sheet 320 .

[0032] Specifically, when a light beam in a parallel polarization state enters the polarization beam splitter prism 200, it will be incident on the polarization beam splitter film 210 and transmitted to the half-wave plate 310 through the polarization beam splitter film 210. When a light beam in a vertical polarization state enters the polarization beam splitter prism 200, it will also be incident on the polarization beam splitter film 210 and reflected to the first high-reflection film 220 through the polarization beam splitter film 210 and reflected again to the glass sheet 320 through the first high-reflection film 220.

[0033] In one embodiment, reference Figure 1 and Figure 2 The depolarizing light combining prism 400 is provided with a second high-reflection film 410, a depolarizing beam splitting film 420 and an absorption film 430. The second high-reflection film 410 is used to reflect the incident vertically polarized light. The depolarizing light combining prism 400 is also provided with a depolarizing beam splitting film 420 for semi-transmitting and semi-reflecting the vertically polarized light reflected by the second high-reflection film 410. The absorption film 430 is used to absorb the light beam transmitted or reflected by the depolarizing beam splitting film 420.

[0034] Specifically, when the light beam in the parallel polarization state is converted into the vertical polarization state by the half-wave plate 310, the converted vertical polarized light will be incident on the second high-reflection film 410, and reflected by the second high-reflection film 410 to the depolarization splitter film 420. The depolarization splitter film 420 transmits a part of the converted vertical polarized light to the absorption film 430 for absorption, and reflects the other part to the converging lens 500; when the light beam in the vertical polarization state is transmitted through the glass sheet 320, it will be incident on the depolarization splitter film 420. The depolarization splitter film 420 transmits a part of the light beam in the vertical polarization state to the converging lens 500, and reflects the other part to the absorption film 430 for absorption.

[0035] like Figure 3 As shown, the present invention also provides a specific embodiment of an optical module.

[0036] An optical module, reference Figure 3 The optical module includes the above-mentioned polarization conversion device and also includes a photonic chip 700, and the photonic chip 700 is arranged on the light output side of the polarization conversion device.

[0037] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A polarization conversion device, characterized in that: include: An optical fiber array, a polarization beam splitter prism, a wave plate, a depolarization light combining prism and a converging lens are sequentially arranged, and a light beam enters the polarization beam splitter prism from the optical fiber array, wherein parallel polarized light is transmitted to the wave plate through the polarization beam splitter prism, is converted into a vertical polarization state through the wave plate, and then enters the depolarization light combining prism, and then enters the converging lens through the depolarization light combining prism, and then enters the converging lens, and vertical polarized light sequentially passes through the polarization beam splitter prism, the wave plate and the depolarization light combining prism, and then enters the converging lens, and the two beams of vertical polarized light incident on the converging lens are focused by the converging lens and then output.

2. The polarization conversion device according to claim 1, characterized in that: One end of the wave plate is a half-wave plate, and the other end of the wave plate is a glass plate. The parallel polarized light is converted into vertical polarized light by the half-wave plate and then incident on the depolarized light combining prism. The vertical polarized light is transmitted through the glass plate and then incident on the depolarized light combining prism.

3. The polarization conversion device according to claim 1, characterized in that: The glass sheet and the half-wave plate have the same thickness.

4. The polarization conversion device according to claim 2, characterized in that: A polarization beam splitting film is arranged inside the polarization beam splitting prism for transmitting parallel polarized light and reflecting vertical polarized light.

5. The polarization conversion device according to claim 4, characterized in that: A first high-reflection film is also arranged in the polarization beam splitting prism, so as to reflect the vertically polarized light reflected by the polarization beam splitting film into the glass sheet.

6. The polarization conversion device according to claim 2, characterized in that: A second high-reflection film is arranged inside the depolarization light-combining prism to reflect incident vertically polarized light.

7. The polarization conversion device according to claim 6, characterized in that: A depolarizing beam splitting film is also provided in the depolarizing light combining prism for semi-transmitting and semi-reflecting the vertically polarized light reflected by the second high-reflection film.

8. The polarization conversion device according to claim 7, characterized in that: The depolarization light combining prism further comprises an absorption film for absorbing the light beam transmitted or reflected by the depolarization light splitting film.

9. The polarization conversion device according to claim 1, characterized in that: It also includes a collimating lens array, which is arranged between the optical fiber array and the polarization beam splitter prism for light beam collimation.

10. An optical module, characterized in that: It comprises the polarization conversion device as described in any one of claims 1 to 9, and also comprises a photonic chip, wherein the photonic chip is arranged on the light output side of the polarization conversion device.

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