Monolithic integrated dual-polarization coherent receiving chip, optical assembly and optical module

Abstract

The invention discloses a monolithic integrated dual-polarization coherent receiving chip, which comprises a signal light side optical path, a local oscillation light side optical path and a coherent detection unit, and is characterized in that X / Y dual-polarized light I is split to two frequency mixers through an on-chip optical device I; splitting the polarized light II to two frequency mixers through a second power beam splitter or a first power beam splitter by an on-chip optical device II; and the two frequency mixers are used for mixing any received light to the corresponding photoelectric detector group for photoelectric conversion. An on-chip optical device with a polarization beam splitting function is used on a light path of a local oscillator light side, so that the light path of the local oscillator light side also supports X and Y polarized light input, under the condition of not increasing a non-standard optical interface and using an external device, a chip can work normally by inputting X polarized local oscillator light, and the optical path of the local oscillator light side can be changed into a non-standard optical path. The mixing angle of the chip can be tested by inputting X and Y mixed polarization local oscillation light, and the difficulty and cost of screening the chip are reduced.

Description

Technical Field

[0001] The present invention relates to the field of optical technologies, and particularly to a monolithic integrated dual-polarization coherent receiving chip, an optical component, and an optical module. Background Art

[0002] Coherent detection is a technology that interferes the received signal light with the local oscillator light generated by a local laser and extracts the output interference light signal. Compared with the traditional intensity direct detection technology, this technology has the advantages of supporting multiple modulation formats and high spectral utilization efficiency. At the same time, since coherent detection can retain the phase information of the optical signal, when performing digital signal processing, linear transmission impairments of signals such as the group velocity dispersion and polarization mode dispersion of the optical fiber are relatively easy to effectively equalize. This technology relies on an integrated coherent receiver.

[0003] The dual-polarization coherent receiving chip is the core of the integrated coherent receiver, and its function is to interfere the signal light with the local oscillator light and convert the interference output light into an electrical signal. The mixing angle, that is, the phase error of the 90-degree mixer on the chip, is a parameter that is difficult to test and is crucial for performance. Before packaging the dual-polarization coherent receiving chip into an integrated coherent receiver, if a dual-polarization coherent receiving chip with a qualified mixing angle can be screened in advance, it is of great significance for ensuring the performance of the integrated coherent receiver.

[0004] Currently at the chip level, there are two methods to test the mixing angle of the dual-polarization coherent receiving chip. One method requires relying on a complex external test device. Taking the example of inputting X / Y dual-polarized light at the signal light port and X-polarized light at the local oscillator light port, when testing the mixing angle of the coherent receiving chip in the chip, it is necessary to input coherent light that meets a specific optical path difference range from both the signal light port and the local oscillator light port through an external device, which undoubtedly increases the test difficulty and cost. The other is to add an optical interface on the chip, but adding a non-standard optical interface will reduce the product compatibility, and it may cause light to be input or output from the non-standard optical interface, with a potential risk of signal crosstalk.

[0005] That is to say, the current measures taken at least include the following three problems: 1) Connecting other complex test devices externally from two ports respectively, the test process is cumbersome, the operation is complex, and the cost is high; 2) When adding a non-standard optical interface, there are compatibility problems, resulting in reduced product compatibility; 3) There may be signal crosstalk, leading to problems with accuracy and performance. Summary of the Invention

[0006] In view of the above three problems, the object of the present invention is to propose a monolithic integrated dual-polarization coherent receiving chip, an optical component and an optical module. By using an on-chip optical device with a polarization beam splitting function on the local oscillator optical path, it is possible to allow the local oscillator optical path to also support multiple polarized light inputs. Without adding non-standard optical interfaces and using other external devices, it is possible to input the local oscillator light with Y polarization from the local oscillator light port, and then evenly transmit the optical signals after splitting the local oscillator light through two power splitters to two 90-degree mixers respectively, and then complete the mixing interference and input it into the photodetector. When the local oscillator light port inputs the local oscillator light with X polarization, the chip can be in a normal working mode and mix and interfere with the dual-polarization signal light input from the signal light port. When the local oscillator light port inputs the local oscillator light with a mixed polarization of X and Y, the mixing angle can be conveniently tested, reducing the difficulty and cost of screening the chip.

[0007] It is achieved by the following technical solutions: First, a monolithic integrated dual-polarization coherent receiving chip is proposed, which includes an optical path on the signal light side, an optical path on the local oscillator light side, and a coherent detection unit for receiving and processing the two test optical paths. The optical path on the signal light side at least includes an on-chip optical device I corresponding to the signal light. The optical path on the local oscillator light side at least includes an on-chip optical device II corresponding to the local oscillator light, a second power splitter, and a first power splitter. The coherent detection unit includes a first 90-degree mixer, a first photodetector group, a second 90-degree mixer, and a second photodetector group. Among them, the on-chip optical device I is used to split the incident X / Y dual-polarized light I into the first 90-degree mixer and the second 90-degree mixer. The on-chip optical device II is used to split the incident polarized light II into the first 90-degree mixer and the second 90-degree mixer through the second power splitter, or split it into the first 90-degree mixer and the second 90-degree mixer through the first power splitter. The first 90-degree mixer is used to mix any received light beam into the first photodetector group, and the second 90-degree mixer is used to mix any received light beam into the second photodetector group. Both the first photodetector group and the second photodetector group are used for photoelectric conversion.

[0008] By using on-chip optical devices with a polarization beam splitting function on both of the two test optical paths, it is allowed that both the signal light and the local oscillator light support multiple polarized light inputs at both ends, without the need to externally connect other complex devices. Also, the optical signals after splitting the local oscillator light are evenly transmitted to the two 90-degree mixers respectively through two power splitters, and then the mixing interference is completed, which is convenient for accurately extracting phase and amplitude information after subsequent photoelectric conversion.

[0009] Preferably, the on-chip optical device I uses a signal light port and a first polarization beam splitter, and the first polarization beam splitter is used to perform corresponding beam splitting on the X / Y dual-polarized light I received by the signal light port; the on-chip optical device II uses a local oscillator light port and a second polarization beam splitter, and the second polarization beam splitter is used to perform corresponding beam splitting on the polarized light II received by the local oscillator light port. By using the corresponding ports and polarization beam splitters, the input light beam can be effectively and accurately split.

[0010] Preferably, the on-chip optical device I transmits the X / Y dual-polarized light I to the first 90-degree mixer through the first monitoring attenuation optical path, and also transmits it to the second 90-degree mixer through the second monitoring attenuation optical path; the on-chip optical device II transmits the polarized light II to the first power splitter through the third monitoring attenuation optical path. The monitoring attenuation optical path can effectively adjust the light intensity, ensure the power balance between different lights at the two input ends, help protect the instrument, and enable fine control to enhance the accuracy and stability.

[0011] Preferably, a cuttable optical path is provided between the on-chip optical device II and the second power splitter, which is used to control the optical attenuation when the polarized light II is correspondingly split to the second power splitter. Adding a cuttable optical path can flexibly adjust the intensity of the optical signal and improve the overall adaptability and reliability.

[0012] Preferably, the cuttable optical path uses an adjustable optical attenuator, or a Mach-Zehnder interferometer optical switch with low random initial phase error, or a heavily doped optical waveguide. The adjustable optical attenuator can achieve attenuation of the passing light based on an externally applied electrical bias, that is, the test optical path crosstalk can be eliminated through the electrical bias during normal use; the Mach-Zehnder interferometer optical switch with low random initial phase error can ensure that when only operating in the test mixing angle working mode, the test optical path is turned on when an electrical bias is applied, while in the traditional working mode, no electrical bias is applied to the test optical path and it is in a normally closed state, and light cannot pass through; the heavily doped optical waveguide can be burned out under a large current to prevent light from passing through this path, that is, after the mixing angle is measured on the chip, a large current can be injected into the test optical path to burn out the test optical path without affecting the normal working mode.

[0013] Preferably, the first 90-degree mixer is of seven-channel type or eight-channel type. When using the eight-channel type, the second power splitter uses a 1-to-4 power splitting optical path. The 1-to-4 power splitting optical path has four output channels, which can be respectively input into two mixers in pairs.

[0014] Preferably, the 1-to-4 power splitting optical path uses a star splitter, or a cascaded Y-branch, or a cascaded multimode interferometer. The star splitter, cascaded Y-branch, or cascaded multimode interferometer can all effectively output the required beam splitting ratio for multiple channels. The star splitter has low cost and is easy to integrate. The cascaded Y-branch can flexibly configure its own output beam splitting ratio. The cascaded multimode interferometer has high precision and stability and is suitable for high-requirement application scenarios.

[0015] Preferably, the on-chip optical device I adopts a signal optical port of a polarization beam splitting grating type, and the on-chip optical device II adopts a local oscillator optical port of a polarization beam splitting grating type, which is used to support X / Y dual-polarization input at both ends and perform corresponding beam splitting in the TE polarization. Both ports adopt the polarization beam splitting grating type, which can accurately decompose light into the form of TE polarization, and can replace the form of connecting the local oscillator optical port to the second polarization beam splitter, simplifying the structure.

[0016] Secondly, an optical component is proposed, which includes the monolithic integrated dual-polarization coherent receiving chip as described in any one of the above.

[0017] In addition, an optical module is also proposed, which includes the optical component as described above.

[0018] The beneficial effects of the present invention compared with the prior art are: The technical solution of the present invention, by using an on-chip optical device with a polarization beam splitting function on the local oscillator optical path, can effectively allow the local oscillator optical path to also support the input of multiple polarized lights. Without adding non-standard optical interfaces and using other external devices, in addition to supporting the input of the local oscillator light with X polarization to make the chip work in the conventional mode, the local oscillator optical port also allows the input of the local oscillator light with Y polarization. And by inputting the local oscillator light with mixed X and Y polarizations from the local oscillator optical port, the mixing angle of the chip can be tested, reducing the difficulty and cost of screening the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of Embodiment 1 of a monolithic integrated dual-polarization coherent receiving chip; Figure 2 It is a schematic structural diagram of Embodiment 2 of a monolithic integrated dual-polarization coherent receiving chip; Figure 3 It is a schematic structural diagram of Embodiment 3 of a monolithic integrated dual-polarization coherent receiving chip; Figure 4 It is a schematic structural diagram of Embodiment 4 of a monolithic integrated dual-polarization coherent receiving chip; Figure 5 It is a schematic structural diagram of Embodiment 5 of a monolithic integrated dual-polarization coherent receiving chip; Figure 6 It is a schematic structural diagram of a seven-channel 90-degree mixer; Figure 7 It is a schematic structural diagram of an eight-channel 90-degree mixer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following will combine the attached Figures 1 to 7 in the embodiments of the present invention to describe the technical solutions in the embodiments of the present invention in detail.

[0021] A monolithic integrated dual-polarization coherent receiving chip includes an optical path on the signal light side, an optical path on the local oscillator light side, and a coherent detection unit for receiving and processing two test optical paths. The optical path on the signal light side serves as the input path for the signal light, the optical path on the local oscillator light side serves as the input path for the local oscillator light, and the coherent detection unit performs mixing and optoelectronic conversion to output an electrical signal.

[0022] The optical path on the signal light side at least includes an on-chip optical device I corresponding to the signal light. The optical path on the local oscillator light side at least includes an on-chip optical device II corresponding to the local oscillator light, a second power splitter 420, and a first power splitter 410. The coherent detection unit includes a first 90-degree mixer 511, a first photodetector group 610, a second 90-degree mixer 521, and a second photodetector group 620. Among them, the on-chip optical device I is used to split the incident X / Y dual-polarized light I into the first 90-degree mixer 511 and the second 90-degree mixer 521. The on-chip optical device II is used to split the incident polarized light II into the first 90-degree mixer 511 and the second 90-degree mixer 521 through the second power splitter 420, or split it into the first 90-degree mixer 511 and the second 90-degree mixer 521 through the first power splitter 410. The first 90-degree mixer 511 is used to mix any received light beam into the first photodetector group 610, and the second 90-degree mixer 521 is used to mix any received light beam into the second photodetector group 620. Both the first photodetector group 610 and the second photodetector group 620 are used for optoelectronic conversion.

[0023] It should be noted that in the X / Y dual-polarized light I here, X and Y are defined based on the coordinate system, which means that there are two different polarization states of the signal light with a difference of 90 degrees. Both power splitters are of the specification with a splitting ratio of 50%:50%, so as to evenly split when splitting.

[0024] As Figure 1 shown, it is a schematic structural diagram of Embodiment 1 of a monolithic integrated dual-polarization coherent receiving chip. A plurality of monitoring attenuation optical paths are added to the chip. The monitoring attenuation optical paths can effectively adjust the light intensity, ensure the power balance between different lights at the two input ends, help protect the instrument and perform fine control to enhance the accuracy and stability. Both mixers are seven-channel 90-degree mixers. In the figure, the solid line, the short dash line, and the dotted line are respectively used to represent the parts used in the traditional working mode, the parts used only in the test mixing angle working mode, and the parts required in both the traditional working mode and the test mixing angle working mode. That is, the traditional working mode is the path of the solid line + the dotted line, and the test mixing angle working mode only is the path of the short dash line + the dotted line.

[0025] In this embodiment, the on-chip optical device I adopts a signal optical port 110 and a first polarization beam splitter 210. The first polarization beam splitter 210 is used to split the X / Y dual-polarized light I received by the signal optical port 110 correspondingly. That is, the X-polarized light is split to the first monitoring attenuation optical path 310 and then transmitted to the first 90-degree mixer 511; the Y-polarized light is split to the second monitoring attenuation optical path 320 and then transmitted to the second 90-degree mixer 521.

[0026] The on-chip optical device II adopts a local oscillator optical port 120 and a second polarization beam splitter 220. The second polarization beam splitter 220 is used to split the polarized light II received by the local oscillator optical port 120 correspondingly. When the second polarization beam splitter splits the polarized light II, the X-polarized light is split to the third monitoring attenuation optical path 330 and then reaches the first power splitter 410, and the Y-polarized light is split to the second power splitter 420.

[0027] As Figure 6 shown, it is a schematic structural diagram of a seven-channel 90-degree mixer, which adopts three 2×2 multimode interferometers and one 1×2 multimode interferometer, and altogether includes seven channels A, B, C, D, E, F, G. A, B, and C are used as inputs, and D, E, F, and G are used as outputs. A is used to connect the first power splitter 410; B and C are respectively used to connect the second power splitter 420 and the corresponding monitoring attenuation optical path, and the two ports of B and C do not need to be limited, and their connection methods can be interchanged.

[0028] When the signal optical port 110 is normally incident with light and the incident light of the local oscillator optical port 120 is X-polarized, the optical waveguides represented by solid lines and dotted lines and the on-chip optical devices connected thereto form an optical path of a traditional working mode. When it is necessary to test the mixing angle of the chip, the signal optical port 110 can be not incident with light, and the local oscillator optical port 120 inputs a mixed polarized light with a polarization angle close to 45 degrees or 135 degrees; after passing through the second polarization beam splitter 220, it is divided into two coherent light beams with a power ratio of 50%:50%; one of them is divided into two beams after passing through the second power splitter 420 and enters two mixers, which is called the test light, and the optical path passed through is called the test optical path; the other beam is divided into two beams after passing through the third monitoring attenuation optical path 330 and the first power splitter 410 and enters two mixers, which is the local oscillator light. In the two mixers, the test light replaces the signal light to interfere with the local oscillator light, and four output lights are output from each, and enter the first and second photodetector groups 610 and 620. Then, the mixing angle of the chip can be calculated by detecting the electrical signals output by 610 and 620.

[0029] As Figure 2As shown in the figure, it is a schematic structural diagram of Embodiment 2 of a monolithic integrated dual-polarization coherent receiving chip. Between the on-chip optical device II and the second power splitter, a light path 710 that can be cut off can also be provided to control the optical attenuation when the polarization light II is split to the second power splitter 420. Adding the light path that can be cut off can flexibly adjust the intensity of the optical signal and improve the overall adaptability and reliability.

[0030] In this embodiment, the light path 710 that can be cut off adopts an optical variable attenuator, or a Mach-Zehnder interferometer optical switch with low random initial phase error, or a heavily doped optical waveguide. The optical variable attenuator can achieve the attenuation of the passing light based on an externally applied electrical bias, that is, the test optical path crosstalk can be eliminated through the electrical bias during normal use; the Mach-Zehnder interferometer optical switch with low random initial phase error can ensure that only when working in the test mixing angle working mode, the test optical path is turned on when an electrical bias is applied, while in the traditional working mode, no electrical bias is applied to the test optical path and it is in a normally closed state, and light cannot pass through; the heavily doped optical waveguide can be burned out under a large current to prevent light from passing through this path, that is, after the mixing angle of the chip is measured, a large current can be injected into the test optical path to burn out the test optical path without affecting the normal working mode.

[0031] The problem to be solved by setting the light path 710 that can be cut off is: to prevent the input light at the local oscillator optical port from not being pure X polarization due to the low accuracy of the fiber alignment angle in the traditional working mode, and the light passing through the test optical path enters the 90-degree mixer to interfere with the interference of the signal light and the local oscillator light.

[0032] As Figure 3 shown in the figure, it is a schematic structural diagram of Embodiment 3 of a monolithic integrated dual-polarization coherent receiving chip. The first 90-degree mixer 511 can be of a seven-channel type or an eight-channel type. When the eight-channel type is adopted, the second power splitter 420 adopts a 1-to-4 power splitting optical path 810. The 1-to-4 power splitting optical path has four output channels, which can be respectively input into two mixers in pairs.

[0033] At this time, the working conditions of the mixing angle test mode are: the input light polarization at the local oscillator optical port 120 is Y polarization. After passing through the second polarization beam splitter 220, the input Y-polarized light is split to the light path 710 that can be cut off and becomes TE-polarized light in the chip, that is, transverse electric polarized light, and then enters the 1-to-4 power splitting optical path 810. The 1-to-4 power splitting optical path 810 satisfies a splitting ratio of 25%:25%:25%:25%. The four evenly split test lights are respectively input into the corresponding vacant input ports of two eight-channel 90-degree mixers and interfere in both mixers, each obtaining four output lights, which are output to the first and second photodetector groups 610 and 620. Then, the mixing angle of the chip can be calculated by detecting the electrical signals output by 610 and 620.

[0034] AsFigure 7 As shown, it is a schematic structural diagram of an eight-channel 90-degree mixer, which is a 4×4 multimode interferometer, including a total of eight channels H, I, J, K, L, M, N, and O. Among them, H, I, J, and K are all used as input ends, and L, M, N, and O are all used as output ends.

[0035] In this embodiment, the 1×4 power splitting optical path 810 adopts a star splitter or a cascaded Y-branch or a cascaded multimode interferometer. A star splitter, a cascaded Y-branch, or a cascaded multimode interferometer can all effectively achieve the splitting ratio required for multi-channel output. The star splitter has a low cost and is easy to integrate. The cascaded Y-branch can flexibly configure its own output splitting ratio. The cascaded multimode interferometer has high precision and stability and is suitable for high-requirement application scenarios.

[0036] As Figure 4 shown, it is a schematic structural diagram of Embodiment 4 of a monolithic integrated dual-polarization coherent receiver chip, which uses a seven-channel 90-degree mixer; as Figure 5 shown, it is a schematic structural diagram of Embodiment 5 of a monolithic integrated dual-polarization coherent receiver chip, which uses an eight-channel 90-degree mixer. Combining Figure 4 and Figure 5 shown, at the two input ends of the chip, polarization beam splitting grating type ports can also be used, which is equivalent to replacing the functions of the input ports and the corresponding polarization beam splitters to simplify the structure. The on-chip optical device I uses a polarization beam splitting grating type signal light port 111, and the on-chip optical device II uses a polarization beam splitting grating type local oscillator light port 122, which is used to support dual X / Y polarization input at both ends and perform corresponding beam splitting in the TE polarization. Both ports use the polarization beam splitting grating type, which can accurately decompose the light into the TE polarization form and can replace the form of connecting the local oscillator light port to the second polarization beam splitter to simplify the structure.

[0037] Secondly, an optical component is proposed, and the optical component includes the monolithic integrated dual-polarization coherent receiver chip as described in any one of the above.

[0038] In addition, an optical module is also proposed, and the optical module includes the optical component as described above.

[0039] In summary, by using an on-chip optical device with a polarization beam splitting function on the local oscillator light path, the present invention can effectively allow the local oscillator light path to also support the input of multiple polarized lights. Without adding non-standard optical interfaces and using other external devices, allowing the input of the local oscillator light with Y polarization can test the mixing angle, reducing the difficulty and cost of screening chips; it also uses two power splitters to evenly transmit the optical signals after splitting the local oscillator light to two 90-degree mixers respectively, and then completes the mixing interference, which is convenient for accurately extracting phase and amplitude information after subsequent optoelectronic conversion, and has significant progressiveness.

[0040] The above embodiments are only used to illustrate the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the present invention.

Claims

1. A monolithic integrated dual-polarization coherent receiving chip, characterized in that: The invention comprises a signal light side optical path, a local oscillator light side optical path and a coherent detection unit for receiving and processing the two optical paths, wherein the signal light side optical path at least comprises an on-chip optical device I corresponding to the signal light, the local oscillator light side optical path at least comprises an on-chip optical device II corresponding to the local oscillator light, a second power beam splitter (420) and a first power beam splitter (410), and the coherent detection unit comprises a first 90-degree mixer (511), a first photodetector group (610), a second 90-degree mixer (521) and a second photodetector group (620); The on-chip optical device I is used to split incident X / Y dual polarized light I into a first 90-degree mixer (511) and a second 90-degree mixer (521); the on-chip optical device II is used to split incident polarized light II into the first 90-degree mixer (511) and the second 90-degree mixer (521) through a second power beam splitter (420), or into the first 90-degree mixer (511) and the second 90-degree mixer (521) through a first power beam splitter (410); the first 90-degree mixer (511) is used to mix any received light beam into a first photodetector group (610), and the second 90-degree mixer (521) is used to mix any received light beam into a second photodetector group (620); and both the first photodetector group (610) and the second photodetector group (620) are used to perform photoelectric conversion.

2. The monolithic integrated dual-polarization coherent receiving chip according to claim 1, characterized in that: The on-chip optical device I adopts a signal light port (110) and a first polarization beam splitter (210), and the first polarization beam splitter (210) is used to perform corresponding beam splitting on the X / Y dual polarization light I received by the signal light port (110); the on-chip optical device II adopts a local oscillator light port (120) and a second polarization beam splitter (220), and the second polarization beam splitter (220) is used to perform corresponding beam splitting on the polarization light II received by the local oscillator light port (120).

3. The monolithic integrated dual-polarization coherent receiving chip according to claim 1, characterized in that: The on-chip optical device I transmits X / Y dual polarized light I to a first 90-degree mixer (511) through a first monitoring attenuation optical path (310), and also transmits it to a second 90-degree mixer (521) through a second monitoring attenuation optical path (320); the on-chip optical device II transmits polarized light II to a first power beam splitter (410) through a third monitoring attenuation optical path (330).

4. The monolithic integrated dual-polarization coherent receiving chip according to claim 1, characterized in that: A cuttable optical path (710) is provided between the on-chip optical device II and the second power beam splitter (420) for controlling the optical attenuation of the polarized light II when it is correspondingly split to the second power beam splitter (420).

5. The monolithic integrated dual-polarization coherent receiving chip according to claim 4, characterized in that: The cut-off optical path (710) adopts an adjustable optical attenuator, or a Mach-Zehnder interferometer optical switch with low random initial phase error, or a heavily doped optical waveguide.

6. The monolithic integrated dual-polarization coherent receiving chip according to claim 1, characterized in that: The first 90-degree mixer (511) is of a seven-channel type or an eight-channel type. When the eight-channel type is adopted, the second power beam splitter (420) adopts a 1-to-4 power beam splitting optical path (810).

7. The monolithic integrated dual-polarization coherent receiving chip according to claim 6, characterized in that: The 1-to-4 power beam splitting optical path (810) adopts a star beam splitter or a cascaded Y branch or a cascaded multi-mode interferometer.

8. The monolithic integrated dual-polarization coherent receiving chip according to claim 1, characterized in that: The on-chip optical device I adopts a polarization beam splitting grating type signal light port (111), and the on-chip optical device II adopts a polarization beam splitting grating type local oscillator light port (122), which are used to support X / Y dual polarization input at both ends and perform corresponding beam splitting with TE polarization.

9. An optical component, characterized in that: The optical component comprises a monolithically integrated dual-polarization coherent receiving chip as claimed in any one of claims 1 to 8.

10. An optical module, characterized in that: The optical module comprises the optical assembly as claimed in claim 9.

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