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CN-114465089-B - Laser and preparation method thereof

CN114465089BCN 114465089 BCN114465089 BCN 114465089BCN-114465089-B

Abstract

The invention discloses a laser and a preparation method of the laser, wherein the laser comprises a distributed feedback laser and a filter, the distributed feedback laser comprises an active layer, a coupling layer and a passive layer, a light field generated in the active layer is coupled into the passive layer through the coupling layer to be transmitted and enters the filter, the filter comprises a straight waveguide and an annular waveguide, the straight waveguide and the annular waveguide are made of extended passive layers, and the filter has the function of shaping signals of the distributed feedback laser. The distributed feedback laser and the filter can be integrated without butt-joint growth, the chirp problem of the distributed feedback laser during direct modulation can be effectively reduced, the distributed feedback laser has the advantages of low chirp, large extinction ratio, low power consumption, simple process and the like, can replace an electroabsorption modulated laser to be applied to long-distance transmission, and has the advantages of simpler manufacturing process, lower cost, reasonable structural design and wider application range.

Inventors

  • ZHU RUI

Assignees

  • 中兴光电子技术有限公司
  • 中兴光电子技术有限公司

Dates

Publication Date
20260421
Application Date
20201022
Priority Date
20201022

Claims (14)

  1. 1. A laser device, which comprises a laser body, characterized by comprising the following steps: The distributed feedback laser comprises an active layer, a coupling layer and a passive layer, wherein the coupling layer is positioned between the active layer and the passive layer, the coupling layer is used for coupling an optical field generated in the active layer to the passive layer for transmission, and the material band gap of the passive layer is larger than that of the active layer; A filter comprising a straight waveguide and an annular waveguide, the straight waveguide and the annular waveguide being optically field-coupled, the passive layer extending to form the straight waveguide to monolithically integrate the filter with the distributed feedback laser; a substrate, the distributed feedback laser and the filter being formed on the substrate.
  2. 2. The laser of claim 1, wherein the active layer, the coupling layer, and the passive layer form a waveguide region that tapers near an end of the filter.
  3. 3. The laser of claim 2, wherein the tapered portion of the waveguide region has a wedge-shaped cross-section.
  4. 4. The laser of claim 1, wherein the straight waveguide and the annular waveguide are each made of the extended passive layer, the straight waveguide and the annular waveguide being in the same plane and having the same waveguide structure.
  5. 5. The laser of claim 1, wherein the annular waveguide includes a straight edge parallel to the straight waveguide, a gap between the straight edge and the straight waveguide ranging from submicron to micron, such that a coupling region is formed between the straight waveguide and the annular waveguide.
  6. 6. The laser of claim 1 or 5, wherein the annular waveguide is a racetrack racetrack or a rectangular annular structure, and the rectangular apex angle positions of the rectangular annular structure are respectively provided with a total reflection mirror.
  7. 7. The laser of claim 1, wherein a thermal tuning resistor for thermally tuning the resonant wavelength of the filter is provided inside the annular waveguide.
  8. 8. The laser of claim 1, wherein an end of the straight waveguide is provided with a mode spot-size converter for reducing coupling loss of the laser with an external optical fiber.
  9. 9. The laser of claim 1, wherein the substrate material is indium phosphide.
  10. 10. A method of manufacturing a laser, characterized in that it is applied to a laser as claimed in any one of claims 1 to 9, said method comprising: sequentially growing a passive layer, a coupling layer and an active layer on a substrate, wherein the material band gap of the passive layer is larger than that of the active layer; removing part of the active layer and the layer structure above the active layer to form a filter region; and etching the passive layer and the coupling layer in the filter region to form a straight waveguide and a ring waveguide so as to enable optical field coupling between the straight waveguide and the ring waveguide.
  11. 11. The method of manufacturing a laser of claim 10, further comprising: and etching each layer close to the filter area, including the passive layer, the coupling layer and the active layer, so as to form a wedge-shaped waveguide.
  12. 12. The method of manufacturing a laser of claim 10, further comprising: and manufacturing a thermal tuning resistor on the inner side of the annular waveguide.
  13. 13. An optical communication device comprising a laser as claimed in any one of claims 1 to 9.
  14. 14. An optical network system comprising an optical line terminal and a plurality of optical network units, the optical line terminal being connected to the plurality of optical network units by an optical distribution network, wherein the optical line terminal and/or the optical network units comprise a laser as claimed in any one of claims 1 to 9.

Description

Laser and preparation method thereof Technical Field The present invention relates to the field of optoelectronics technologies, and in particular, to a laser, a method for manufacturing the laser, an optical communication device, and an optical network system. Background In recent years, with the rapid development of internet services, cost, size and power consumption have become the price of optical devices moving toward large bandwidths, high rates and long distances. Lasers are commonly classified as core devices in communication network optical devices into direct modulation lasers and external modulation lasers. Distributed feedback laser (Distributed Feedback Laser, DFB) is a directly modulated laser that is widely used for medium-short range (below 10 km) transmission due to its low cost, small size, high speed and high linearity. However, in the direct tuning process, the thermal effect and the variation of the injection current change the effective refractive index of the active region of the laser, and cause wavelength drift and chirp, which is one of the limiting factors in the application of DFB to optical fiber transmission links above 10 km. Accordingly, an electroabsorption modulated laser (Electroabsorption Modulated Laser, EML) is a typical external modulation laser, in which a DFB is integrated with an electroabsorption modulator (Electroabsorption Modulator, EAM) by a Butt-growth technique (button-joint), and an electrical signal is applied to the EAM for external modulation. The EML has the advantages of high speed, high extinction ratio, low chirp and the like, and can be applied to long-distance transmission of more than 40 km. However, EML is difficult to manufacture, and has high power consumption and high cost, which limit its large-scale use in optical communication networks. Disclosure of Invention The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides the laser, the preparation method of the laser, the optical communication equipment and the optical network system, which can effectively reduce the chirp problem during the direct tuning of the DFB, and have the advantages of high extinction ratio, low power consumption and the like, and are more practical and reliable. In a first aspect, an embodiment of the present invention provides a laser, including: a distributed feedback laser comprising an active layer, a coupling layer and a passive layer, the coupling layer being located between the active layer and the passive layer, the coupling layer being for coupling an optical field generated in the active layer to the passive layer for transmission; A filter comprising a straight waveguide and an annular waveguide, the straight waveguide and the annular waveguide being optically field-coupled, the passive layer extending to form the straight waveguide to monolithically integrate the filter with the distributed feedback laser; a substrate, the distributed feedback laser and the filter being formed on the substrate. In a second aspect, the present invention further provides a method for preparing a laser, including: Sequentially growing a passive layer, a coupling layer and an active layer on a substrate; removing part of the active layer and the layer structure above to form a filter area; and etching the passive layer and the coupling layer in the filter region to form a straight waveguide and a ring waveguide so as to enable optical field coupling between the straight waveguide and the ring waveguide. In a third aspect, the present invention further provides an optical communication device, including the laser according to the embodiment of the first aspect. In a fourth aspect, the present invention further provides an optical network system, which includes an optical line terminal and a plurality of optical network units, where the optical line terminal is connected to the plurality of optical network units through an optical distribution network, and the optical line terminal and/or the optical network units include a laser according to the embodiment of the first aspect. Compared with the traditional DFB, the distributed feedback laser in the embodiment of the invention is added with a passive layer and a coupling layer, the passive layer is extended to form a straight waveguide of the filter, the distributed feedback laser and the filter are monolithically integrated, an optical field generated in an active layer is coupled to the passive layer for transmission through the coupling layer, butt joint growth is not needed between the distributed feedback laser and the filter, the chirp problem during direct adjustment of the DFB is effectively reduced, the distributed feedback laser has the advantages of low chirp, large extinction ratio, low power consumption, simple process and the like, the filter is utilized to reshape the optical field output by the distributed feedback laser to realize low ch