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JP-7855114-B1 - Light source unit

JP7855114B1JP 7855114 B1JP7855114 B1JP 7855114B1JP-7855114-B1

Abstract

[Problem] To provide a light source unit that can suppress light loss while avoiding variations in product quality. [Solution] The optical integrated circuit element 20 includes a plurality of laser elements 10 and a plurality of unit circuits 30 provided on a substrate 22 corresponding to the plurality of laser elements 10. Each of the plurality of unit circuits 30 has an optical input/output end face 31a facing a first end face 10a, which is one end face of the corresponding laser element 10 in the resonance direction X, an input/output waveguide 31, and an optical feedback unit 40 configured to guide light of a predetermined wavelength incident from the corresponding laser element 10 and return light of a predetermined wavelength to the laser element 10, thereby changing the wavelength of the output light Lo1 within a predetermined wavelength range. The corresponding laser element 10 and the optical input/output end face 31a are separated by a predetermined distance d2 in the resonance direction X. The predetermined distance d2 is 100 nm to 5 μm. [Selection Diagram] Figure 2

Inventors

  • 前北 和晃
  • 鈴木 大幾
  • 岩本 健汰
  • 間瀬 光人

Assignees

  • 浜松ホトニクス株式会社

Dates

Publication Date
20260507
Application Date
20250402

Claims (14)

  1. Multiple laser elements with different central wavelengths, The optical integrated circuit element comprises a substrate and a plurality of unit circuits provided on the substrate corresponding to the plurality of laser elements, The plurality of laser elements are arranged along an array direction that is perpendicular to the resonance direction common to the plurality of laser elements and the thickness direction of the substrate. Each of the aforementioned plurality of unit circuits is Among the plurality of laser elements, the optical input/output end face facing the first end face, which is one end face of a corresponding laser element in the resonance direction, An input/output waveguide extending from the aforementioned optical input/output end face, The system includes an optical feedback unit that is optically connected to the input/output waveguide and configured to guide light of a predetermined wavelength incident from the corresponding laser element and return the light of the predetermined wavelength to the corresponding laser element, thereby changing the wavelength of the output light within a predetermined wavelength range. The corresponding laser element and the optical input/output end face are separated by a predetermined distance in the resonance direction. The predetermined distance is 100 nm to 5 μm, in the light source unit.
  2. The light source unit according to claim 1, wherein the predetermined distance is 2 μm or less.
  3. The light source unit according to claim 1, wherein the predetermined distance is 1 μm or less.
  4. An adhesive is filled between at least one of the plurality of laser elements and the optical input/output end face corresponding to the at least one laser element. The light source unit according to claim 1, wherein the adhesive transmits light of a predetermined wavelength range.
  5. The optical integrated circuit element includes a laminate provided on the substrate, in which at least the input/output waveguides of the unit circuit are formed, The light source unit according to claim 4, wherein, when viewed from the thickness direction, a portion of the adhesive overlaps with the laminate.
  6. The light source unit according to any one of claims 1 to 5, wherein the plurality of laser elements include a first laser element and a second laser element having different thicknesses.
  7. The light source unit according to any one of claims 1 to 5, wherein the output light is output from the side of the optical integrated circuit element to the outside of the optical integrated circuit element.
  8. Each of the aforementioned plurality of unit circuits further has an output waveguide into which light from the optical feedback unit is input, The output waveguide includes an output section that outputs the output light to the outside of the optical integrated circuit element. The light source unit according to any one of claims 1 to 5, wherein the distance between two adjacent output units among the plurality of output units is smaller than the width of each of the plurality of laser elements in the arrangement direction.
  9. The light source unit according to any one of claims 1 to 5, wherein at least one of the plurality of laser elements outputs the output light from a second end face opposite to the first end face in the resonance direction.
  10. Each of the plurality of laser elements has an active layer, The light source unit according to any one of claims 1 to 5, wherein the width of the active layer in the aforementioned arrangement direction is greater than the width of the input/output waveguide in the aforementioned arrangement direction at the optical input/output end face.
  11. Each of the plurality of laser elements has an active layer, The light source unit according to any one of claims 1 to 5, wherein the width of the active layer in the aforementioned arrangement direction is smaller than the width of the input/output waveguide in the aforementioned arrangement direction at the optical input/output end face.
  12. The light source unit according to any one of claims 1 to 5, further comprising a cooling element on which the plurality of laser elements and the optical integrated circuit elements are mounted.
  13. The lens portion that transmits the output light, A light source unit according to any one of claims 1 to 5, further comprising a package that houses the plurality of laser elements and the optical integrated circuit elements and also houses or holds the lens portion.
  14. The light source unit according to claim 13, wherein the width of the package in the arrangement direction is greater than the height of the package in the thickness direction.

Description

This disclosure relates to a light source unit. Conventionally, a light source unit comprising multiple laser elements and multiple optical integrated circuit (PIC) elements containing multiple unit circuits is known (for example, Patent Document 1). In such a light source unit, light is emitted from the laser elements to the unit circuits. Of the light incident on the unit circuits, light of a predetermined wavelength is re-incident to the laser elements by the optical feedback section of the unit circuits and amplified inside the laser elements. The light thus amplified is output to the outside of the device as output light. Special Publication No. 2020-520768 Figure 1 shows the cross-sectional structure of the light source unit according to the first embodiment.Figure 2 shows the cross-sectional structure of the light source unit along the line II-II in Figure 1.Figure 3 shows an example configuration of a laser element and a corresponding unit circuit.Figure 4 shows an example of a waveguide configuration.Figure 5 shows the cross-sectional structure of the portion where the laser element and the optical integrated circuit element face each other.Figure 6 is a plan view showing the structure of the area where the laser element and the optical integrated circuit element face each other.Figure 7 shows an example of the arrangement of power monitors.Figure 8 shows an example of the control configuration of a light source unit.Figure 9 shows an example of pulse timing.Figure 10 shows another example of pulse timing.Figure 11 shows an example of the configuration of an output waveguide.Figure 12 shows a first modified example of the third end face.Figure 13 shows a second modified example of the third end face.Figure 14 shows the cross-sectional structure of the light source unit according to the second embodiment.Figure 15 is a plan view showing the configuration of an optical integrated circuit element in the second embodiment.Figure 16 shows an example configuration of a laser element and a corresponding unit circuit in the second embodiment.Figure 17 shows a first modified example of the wavelength adjustment section.Figure 18 shows a second modified example of the wavelength adjustment section.Figure 19 shows a first modified example of a loop-type optical feedback section.Figure 20 shows a second modified example of a loop-type optical feedback section.Figure 21 shows a modified example of the optical integrated circuit element in the second embodiment.Figure 22 shows a modified example of a waveguide.Figure 23 shows another modified example of the waveguide. Hereinafter, one embodiment of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant explanations will be omitted. The drawings may be simplified or exaggerated in part for ease of understanding. Therefore, the dimensional ratios of the embodiment are not limited to those shown in the drawings. [First Embodiment] As shown in Figures 1 and 2, the light source unit 1 of the first embodiment comprises a plurality of laser elements 10 and an optical integrated circuit element 20. As shown in Figure 2, the optical integrated circuit element 20 has a substrate 22 and a plurality of unit circuits 30 (301-304) provided on the substrate 22. As shown in Figure 3, the unit circuits 30 are composed of various optical elements, including waveguides, provided on the substrate 22. In this embodiment, one unit circuit 30 corresponds to one laser element 10. Hereinafter, the thickness direction of the substrate 22 will be referred to as the thickness direction Z, the common resonance direction of the multiple laser elements 10 will be referred to as the resonance direction X, and the direction perpendicular to the thickness direction Z and the resonance direction X (in this embodiment, the direction in which the multiple laser elements 10 are arranged) will be referred to as the arrangement direction Y. Multiple laser elements 10 and optical integrated circuit elements 20 are housed within the package 2. In the light source unit 1, the package 2 further houses a cooling element 3, a carrier substrate 4, a lens section 5, an output window 6, and a temperature sensor 7, among other components. Package 2 has a bottom wall 2a, a side wall 2b, and a top wall 2c. The bottom wall 2a is a rectangular plate-shaped member whose resonance direction X is the longitudinal direction and whose arrangement direction Y is the short direction. The side wall 2b is connected to the edge of the bottom wall 2a when viewed from the thickness direction Z and extends in the thickness direction Z. That is, when viewed from the thickness direction Z, the side wall 2b is formed in an annular shape (rectangular in this embodiment) so as to surround the internal space in which the optical integrated circuit element 20 etc. is housed. In other w