Tunable laser array

Abstract

The invention provides a tunable laser array. The tunable laser array comprises a gain chip array (101), a lens array (102), a wavelength tuning assembly (103), a wavelength locking assembly (104), an isolation assembly (105), an output optical fiber assembly (106), a thermistor (107) and a TEC (108), the gain chip array (101) comprises a plurality of gain chips, emergent light of the gain chips passes through the lens array (102) to form collimated light beams to be output, the collimated light beams are subjected to laser wavelength mode selection through the wavelength tuning assembly (103), then sequentially pass through the wavelength locking assembly (104) and the isolation assembly (105) and are finally coupled to the output optical fiber group 206, and laser output is completed. According to the technical scheme, integration of a plurality of wide-range narrow-linewidth tunable lasers can be achieved, a tunable laser array is formed, and assembling of downstream products is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic module packaging, in particular to a tunable laser array. Background Art

[0002] Hyperscale data centers currently primarily utilize 400G / 800G / 1.6T pluggable optical modules. To achieve greater capacity and higher integration, the industry is developing optical interfaces using co-packaged optics (CPO) technology, which fundamentally differs from existing optical module interfaces. CPO is a packaging technology that co-packages the optical module and switch chip ASIC onto a minimally sized board. By shortening the distance between the switch chip and the optical engine, the transmission speed of electrical signals between the chip and the engine is significantly improved. However, due to the high power consumption and heat dissipation of switch chips, and the extreme temperature sensitivity of InP-based laser sources, placing the laser source too close to the heat source in the switch chip will inevitably reduce the reliability and performance of the source itself and hinder the heat dissipation of the switch chip. A better solution is to package the laser source separately, leaving only the silicon photonic integrated circuit (PIC), which is insensitive to temperature fluctuations, close to the switch chip. This significantly improves system reliability and maintainability.

[0003] Regarding the specific implementation of the external light source (ELS), if the EML or DFB laser is used as in the built-in light source mode, the inability to change the output wavelength of either EML or DFB laser will undoubtedly greatly limit the switch's ability to continue to expand and upgrade. Furthermore, as the number of wavelengths increases, the cost of preparing EML / DFBs with different wavelengths also increases dramatically. To avoid these problems, using a tunable laser as the external light source has become a more ideal option. However, due to the complex manufacturing process, current tunable lasers generally use a single light source packaging solution. Simply stacking and assembling multiple tunable lasers will result in a very large external light source, which in turn affects the packaging size of the downstream module. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a tunable laser array to realize the integration of multiple wide-range narrow-linewidth tunable lasers to form a tunable laser array, which is convenient for the assembly of downstream products.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical solution: a tunable laser array, comprising a gain chip array (101), a lens array (102), a wavelength tuning component (103), a wavelength locking component (104), an isolation component (105), an output fiber component (106), a thermistor (107) and a TEC (108); the gain chip array (101) comprises a plurality of gain chips, and the output light of the gain chip passes through the lens array (102) to form a collimated light beam output, the collimated light beam passes through the wavelength tuning component (103) for laser wavelength mode selection, and then passes through the wavelength locking component (104) and the isolation component (105) in sequence, and finally is coupled to the output fiber group 206 to complete the laser output; the wavelength locking component (104) is used to monitor the wavelength deviation of multiple laser beams; the gain chip array (101), the lens array (102) and the wavelength tuning component (103) constitute a laser resonant cavity; the isolation component (105) is used to prevent the output light from being reflected or external light from being incident on the laser resonant cavity.

[0006] In a preferred embodiment, the wavelength tuning component (103) comprises 2*N tunable filter elements for performing laser mode selection through a vernier effect, where N represents the number of gain chips.

[0007] In a preferred embodiment, the wavelength locking component (104) includes a beam splitter prism (11), a first power detection group (12), an optical etalon (13), and a second power detection group (14); the beam splitter prism (11), the optical etalon (13), and the second power detection group (14) are arranged in sequence along the incident direction of the laser beam; and the first power detection group (12) is arranged at the bottom of the beam splitter prism (11).

[0008] In a preferred embodiment, the number of the optical etalon (13) is one.

[0009] In a preferred embodiment, the first power detection group (12) includes N photodetectors for collecting N laser powers, and the second power detection group (14) includes N photodetectors for collecting the transmission spectrum power of the N lasers through the optical etalon (13).

[0010] In a preferred embodiment, after the multiple laser beams pass through the beam splitter prism (11), more than 90% of the laser beams will directly pass through the first beam splitting surface of the beam splitter prism (11) and be output as the first sub-beam, and less than 10% of the laser beams will be reflected on the first beam splitting surface of the beam splitter prism (11) and incident on the second beam splitting surface of the beam splitter prism (11), and will be further divided into a transmitted second sub-beam and a reflected third sub-beam on the second beam splitting surface of the beam splitter prism (11), and the power values of the second sub-beam and the third sub-beam are both less than 5% of the original incident power; the second sub-beam is incident on the first power detection group (12), and the third sub-beam is incident on the second power detection group (14) after passing through the optical standard (13); the photoelectric detectors of the first power detection group (12) and the second power detection group (14) collect the optical power of the second sub-beam and the third sub-beam of the multiple laser beams, and combine the transmission spectrum curve of the optical standard (13) to perform wavelength locking on each incident laser beam.

[0011] In a preferred embodiment, the TEC (108) and the thermistor (107) form a PID closed-loop control to control the temperature inside the laser.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1) Realize the integration of multiple wide-range narrow-linewidth tunable lasers to form a tunable laser array, which is convenient for the assembly of downstream products.

[0013] 2) An innovative wavelength locking scheme is adopted, which can wavelength lock multiple lasers of different wavelengths with only one optical etalon, reducing the complexity of wavelength locking of the laser array.

[0014] 3) Compared with the technical solution of simply stacking and assembling multiple tunable lasers, the product cost and packaging size can be greatly reduced due to the sharing of the product's housing, semiconductor refrigeration plate (TEC), PCBA board and some of its electronic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic structural diagram of a tunable laser array according to a preferred embodiment of the present invention; Figure 2 2 is a structural diagram of a wavelength locking component according to a preferred embodiment of the present invention.

[0016] Reference numerals: 101 - gain chip array, 102 - lens array, 103 - wavelength tuning component, 104 - wavelength locking component, 105 - isolation component, 106 - output fiber component, 107 - thermistor, 108 - TEC DETAILED DESCRIPTION

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0019] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application; as used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form, and it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0020] refer to Figure 1-2 The tunable laser array includes a gain chip array 101, a lens array 102, a wavelength tuning component 103, a wavelength locking component 104, an isolation component 105, an output fiber assembly 106, a thermistor 107, and a semiconductor cooler (TEC) 108. The gain chip array 101 includes multiple gain chips. The output light from each gain chip is collimated by the lens array 102 and then passes through the wavelength tuning component 103, the wavelength locking component 104, and the isolation component 105. Finally, it is coupled to the output fiber assembly 106 to complete the laser output. The wavelength tuning component 103 contains 2*N tunable filter elements, which are used for laser mode selection through the vernier effect. N represents the number of gain chips. The number of laser beams in the tunable laser array corresponds to the number of gain chips in a one-to-one relationship (1:1). The number of laser beams and the number of photodetectors also have a 1:2 relationship, meaning that one laser beam requires two photodetectors. In this patent, the lasers are divided into two groups (power detection groups), so the number of photodetectors in each group also has a 1:1 relationship to the number of laser beams.

[0021] The wavelength locking assembly 104 monitors wavelength drift of the multiple laser beams; the isolation assembly 105 ensures a unidirectional optical path, preventing light from the output circuit from reflecting back into the external cavity laser. The semiconductor cooler TEC 108, along with the resistance value collected by thermistor 107, forms a closed-loop control loop to achieve overall temperature control within the laser. Compared to existing tunable lasers, the tunable laser array of the present invention requires a proportionally larger number of gain chips, wavelength tuning elements, and output fiber components. Furthermore, the wavelength locking and isolation components, TEC, thermistor, package housing, and circuit board all share the same components, significantly reducing product costs.

[0022] The wavelength locking assembly 104 includes a beam splitter prism 11, a first power detection group 12, an optical etalon 13, a second power detection group 34, and a temperature control component for independently controlling the temperature of the optical etalon 13. In this embodiment, the temperature control component is a heating resistor. The multiple laser beams ( Figure 2 Only one path is shown) after passing through the beam splitter prism 11, more than 90% of the light will directly pass through the first beam splitting surface of the beam splitter prism 11 and be output as the first sub-beam 1. Less than 10% of the light will be reflected on the first beam splitting surface and then incident on the second beam splitting surface of the beam splitter prism 11, and will be divided again on the second beam splitting surface into the transmitted second sub-beam 2 and the reflected third sub-beam 3. The power values of the second sub-beam 2 and the third sub-beam 3 are both less than 5% of the original incident power. The second sub-beam 2 is directly incident on the first power detection combination 12, while the third sub-beam 3 is incident on the second power detection group 14 after passing through the optical etalon 13. The first power detection group 13 and the second power detection group 14 both include multiple photodetectors for collecting the optical power of the second sub-beam 2 and the third sub-beam 3 of the multi-path laser. Combined with the transmission spectrum curve of the optical etalon 13, each incident laser beam can be wavelength locked (the wavelength locking principle is a well-known technology in the industry and will not be repeated here). Unlike common industry solutions, the wavelength locking assembly 104 of the present invention utilizes a single optical etalon 13 to simultaneously lock multiple laser beams of different wavelengths, thereby reducing the number of optical etalons used. In particular, optical etalons typically require independent temperature control. Reducing the number of optical etalons also reduces the number of temperature control components, significantly reducing module complexity and cost.

Claims

1. A tunable laser array, characterized in that: The invention comprises a gain chip array (101), a lens array (102), a wavelength tuning component (103), a wavelength locking component (104), an isolation component (105), an output optical fiber component (106), a thermistor (107) and a TEC (108); the gain chip array (101) comprises a plurality of gain chips, and the output light of the gain chip passes through the lens array (102) to form a collimated light beam output, the collimated light beam passes through the wavelength tuning component (103) for laser wavelength mode selection, and then passes through the wavelength locking component (104) and the isolation component (105) in sequence, and finally is coupled to the output optical fiber group 206 to complete the laser output; the wavelength locking component (104) is used to monitor the wavelength deviation of multiple laser beams; the gain chip array (101), the lens array (102) and the wavelength tuning component (103) constitute a laser resonant cavity; the isolation component (105) is used to prevent the output light from being reflected or external light from being incident on the laser resonant cavity.

2. The tunable laser array according to claim 1, characterized in that: The wavelength tuning component (103) comprises 2*N tunable filter elements, which are used for laser mode selection through a vernier effect, where N represents the number of gain chips.

3. The tunable laser array according to claim 1, wherein: The wavelength locking component (104) comprises a beam splitter prism (11), a first power detection group (12), an optical etalon (13), and a second power detection group (14); the beam splitter prism (11), the optical etalon (13), and the second power detection group (14) are arranged in sequence along the incident direction of the laser beam; and the first power detection group (12) is arranged at the bottom of the beam splitter prism (11).

4. The tunable laser array according to claim 3, characterized in that: The number of the optical etalon (13) is 1.

5. The tunable laser array according to claim 3, characterized in that: The first power detection group (12) includes N photodetectors for collecting N laser powers, and the second power detection group (14) includes N photodetectors for collecting the transmission spectrum power of the N lasers through the optical etalon (13).

6. The tunable laser array according to claim 5, characterized in that: After the multiple laser beams pass through the beam splitter prism (11), more than 90% of the laser beams will directly pass through the first beam splitting surface of the beam splitter prism (11) and be output as the first sub-beam. Less than 10% of the laser beams will be reflected on the first beam splitting surface of the beam splitter prism (11) and incident on the second beam splitting surface of the beam splitter prism (11), and will be further divided into a transmitted second sub-beam and a reflected third sub-beam on the second beam splitting surface of the beam splitter prism (11). The power values of the second sub-beam and the third sub-beam are both less than 5% of the original incident power. The second sub-beam is incident on the first power detection group (12), and the third sub-beam is incident on the second power detection group (14) after passing through the optical standard (13). The photoelectric detectors of the first power detection group (12) and the second power detection group (14) collect the optical power of the second sub-beam and the third sub-beam of the multiple laser beams, and lock the wavelength of each incident laser beam in combination with the transmission spectrum curve of the optical standard (13).

7. The tunable laser array according to claim 1, characterized in that: The TEC (108) and the thermistor (107) form a PID closed-loop control to control the temperature inside the laser.

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