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EP-4737956-A1 - WAVELENGTH DIVISION DEVICE AND WAVELENGTH DIVISION DEVICE MANUFACTURING METHOD CAPABLE OF IMPROVING FILTER ALIGNMENT ACCURACY

EP4737956A1EP 4737956 A1EP4737956 A1EP 4737956A1EP-4737956-A1

Abstract

A wavelength division device (100) includes a substrate (10) having one or more grooves (10a), a plurality of filter bars (FB1-FB4) disposed in the one or more grooves (10a) of the substrate (10), and a prism (11) disposed on the substrate (10). Each of the filter bars (FB1-FB4) corresponds to an optical filtering wavelength. The prism (11) is configured to cover the plurality of filter bars (FB1-FB4). A surface of the substrate (10) is etched to form the one or more grooves (10a). After the plurality of filter bars (FB1-FB4) are coated, the plurality of filter bars (FB1-FB4) are bonded in the one or more grooves (10a) of the substrate (10). A resin (20) disposed on the substrate (10) is imprinted by a working mold (30) to form the prism (11).

Inventors

  • KUO, HAN-YI
  • LU, YIN-TUNG
  • HUNG, CHIEN-FENG
  • WU, SHI-JEN

Assignees

  • Himax Technologies Limited

Dates

Publication Date
20260506
Application Date
20250808

Claims (15)

  1. A wavelength division device (100), comprising: a substrate (10); a plurality of coated filter bars (FB1-FB4), wherein each filter bar of the plurality of filter bars corresponds to an optical filtering wavelength; and a prism (11) disposed on the substrate (10) and configured to cover the plurality of filter bars (FB1-FB4); characterized in that: the substrate (10) has one or more grooves (10a) formed on a surface by etching; the plurality of coated filter bars (FB1-FB4) are bonded within the one or more grooves (10a) of the substrate (10); and the prism (11) is formed by a resin (20) disposed on the substrate (10) and imprinted by a working mold (30).
  2. The device (100) of claim 1, characterized in that the one or more grooves (10a) have substantially identical depths (D) and substantially identical widths (W), and the substrate (10) is a glass wafer.
  3. The device (100) of claim 1, characterized in that the plurality of filter bars (FB1-FB4) are coated on their surfaces by different glass coating liquid materials, and the plurality of filter bars (FB1-FB4) are bonded in the one or more grooves (10a) of the substrate (10) by using an adhesive material having a refractive index matching with a glass.
  4. The device (100) of claim 1, characterized in that after the plurality of filter bars (FB1-FB4) are bonded in the one or more grooves (10a) of the substrate (10), the substrate (10) is processed by a thermal curing process for heating an adhesive material between the plurality of filter bars (FB1-FB4) and the one or more grooves (10a), or processed by an ultraviolet (UV) light curing process for transforming the adhesive material from a liquid state to a hardened state.
  5. The device (100) of claim 1, characterized in that the working mold (30) comprises a predetermined pattern (30a) corresponding to the prism (11), the working mold (30) is pressed against the resin (20) with a controlled force for a time duration to form the prism (11), and after the time duration has elapsed, the working mold (30) is removed from the substrate (10).
  6. The device (100) of claim 1, characterized in that the substrate (10) is sawed to adjust a size of the wavelength division device (100).
  7. The device (100) of claim 1, characterized in that the wavelength division device (100) is a wavelength division multiplexer, and the prism (11) comprises: a first surface (P1) configured to receive a plurality of light signals (L11-L14) having a plurality of optical wavelengths; a second surface (P2) disposed adjacent to the first surface (P1) and configured to reflect the plurality of light signals (L11-L14) for generating a plurality of reflected light signals (R11-R14); and a third surface (P3) disposed adjacent to the first surface (P1) and the second surface (P2) and configured to receive the plurality of reflected light signals (R11-R14).
  8. The device (100) of claim 7, characterized in that the plurality of reflected light signals (R11-R14) are received by the plurality of filter bars (FB1-FB4) through the third surface (P3) of the prism (11), and the plurality of reflected light signals (R11-R14) are multiplexed to generate a composite light signal (L_com1) by the substrate (10).
  9. The device (100) of claim 1, characterized in that the wavelength division device (100) is a wavelength division demultiplexer, and the prism (11) comprises: a first surface (P1) configured to output a plurality of reflected light signals (L21-L24); a second surface (P2) disposed adjacent to the first surface (P1) and configured to reflect a plurality of filtered light signals (R21-R24) for generating the plurality of reflected light signals (L21-L24); and a third surface (P3) disposed adjacent to the first surface (P1) and the second surface (P2) and configured to receive the plurality of filtered light signals (R21-R24).
  10. The device (100) of claim 9, characterized in that a composite light signal (L_com2) is demultiplexed and filtered by the substrate (10) and the plurality of filter bars (FB1-FB4) to generate the plurality of filtered light signals (R21-R24).
  11. A wavelength division device manufacturing method, characterized by comprising: etching a surface of a substrate (10) to form one or more grooves (10a); coating a plurality of filter bars (FB1-FB4); bonding the plurality of filter bars (FB1-FB4) in the one or more grooves (10a) of the substrate (10) after the plurality of filter bars (FB1-FB4) are coated; and imprinting a resin (20) disposed on the substrate (10) by a working mold (30) to form a prism (11); wherein each filter bar (FB1-FB4) of the plurality of filter bars corresponds to an optical filtering wavelength , and the prism (11) is disposed on the substrate (10) and configured to cover the plurality of filter bars (FB1-FB4).
  12. The method of claim 11, characterized in that the one or more grooves (10a) have substantially identical depths (D) and substantially identical widths (W), and the substrate (10) is a glass wafer.
  13. The method of claim 11, characterized in that coating the plurality of filter bars (FB1-FB4) is coating surfaces of the plurality of filter bars (FB1-FB4) by different glass coating liquid materials, and bonding the plurality of filter bars (FB1-FB4) is bonding in the one or more grooves (10a) of the substrate (10) by using an adhesive material having a refractive index matching with a glass, the method further comprising: processing a thermal curing process for heating the adhesive material, or processed by an ultraviolet (UV) light curing process for transforming the adhesive material from a liquid state to a hardened state after the plurality of filter bars (FB1-FB4) are bonded in the one or more grooves (10a) of the substrate (10).
  14. The method of claim 11, characterized in that imprinting the resin (20) disposed on the substrate (10) by the working mold (30) to form the prism (11) comprises: pressing against the resin (20) by the working mold (30) with a controlled force for a time duration to form the prism (11); and removing the working mold (30) from the substrate (10) after the time duration has elapsed; wherein the working mold (30) comprises a predetermined pattern (30a) corresponding to the prism (11).
  15. The method of claim 11, characterized by further comprising: sawing the substrate (10) to adjust a size of a wavelength division device (100); wherein the substrate (10), the plurality of filter bars (FB1-FB4), and the prism (11) form the wavelength division device (100).

Description

Field of the Invention The present invention illustrates a wavelength division device and a wavelength division device manufacturing method, and more particularly, a wavelength division device and a wavelength division device manufacturing method capable of improving filter alignment accuracy and reducing bonding alignment process. Background of the Invention Wavelength division multiplexing (WDM) is a technology that uses several lasers to simultaneously transmit multiple beams of lasers with different wavelengths on a single optical fiber. The WDM can be used for transmitting each of the beams separately, or combining beams of several wavelengths of light to transmit them together. Local area network WDM (LWDM) is a wavelength division multiplexing technology based on Ethernet channels. It uses 12 wavelengths ranging from 1269 nm to 1332 nm in an O-band (1260 nm to 1360 nm), with a wavelength spacing of 4 nm. The operating wavelengths of LWDM are characterized by low dispersion and good stability. At the same time, LWDM can increase channel capacity and further save the utilization of optical fibers. Traditional multiplexer and demultiplexer concepts utilize a parallelogram structure and filters to combine and transmit light beams of different wavelengths into an optical fiber. The filters are assembled by bonding. An alternative method is to use a lift-off technology in the filter coating process. However, if the lift-off process is used, based on 4 channels of the LWDM, the coating process and quality are very difficult to achieve. Summary of the Invention The present disclosure aims at providing a wavelength division device and a wavelength division device manufacturing method for achieving high filter alignment accuracy and reducing the complexity of the bonding alignment process. This is achieved by the wavelength division device according to claim 1 and the wavelength division device manufacturing method according to claim 11. The dependent claims pertain to advantageous further developments. Brief Description of the Drawings In the following, the invention is further illustrated by way of example, taking reference to the accompanying drawings. Thereof FIG.1 is a structure of a wavelength division device according to an embodiment of the present invention;FIG.2 illustrates a first stage of manufacturing the wavelength division device in FIG.1;FIG.3 illustrates a second stage of manufacturing the wavelength division device in FIG.1;FIG.4 illustrates a third stage of manufacturing the wavelength division device in FIG.1;FIG.5 illustrates a fourth stage of manufacturing the wavelength division device in FIG.1;FIG.6 illustrates a fifth stage of manufacturing the wavelength division device in FIG.1;FIG.7 illustrates a sixth stage of manufacturing the wavelength division device in FIG.1;FIG.8 illustrates light paths of performing a multiplexing mechanism by the wavelength division device in FIG.1;FIG.9 illustrates light paths of performing a demultiplexing mechanism by the wavelength division device in FIG.1;FIG.10 illustrates coating technologies of a substrate of the wavelength division device in FIG.1 when the multiplexing mechanism is performed;FIG.11 illustrates coating technologies of the substrate of the wavelength division device inFIG.1 when the demultiplexing mechanism is performed; andFIG.12 is a flow chart of manufacturing the wavelength division device in FIG.1. Detailed Description FIG.1 is a structure of a wavelength division device 100 according to an embodiment of the present invention. The wavelength division device 100 can be a wavelength division multiplexer or a wavelength division demultiplexer, which allows a plurality of optical signals with different wavelengths to be transmitted simultaneously over a single optical fiber. The wavelength division device 100 includes a substrate 10, a plurality of filter bars FB1 to FB4, and a prism 11. The substrate 10 can be a base material on which the other components are mounted. In an embodiment, the substrate 10 can be a glass wafer with a plurality of etched grooves. The plurality of filter bars FB1 to FB4 are disposed in the one or more grooves of the substrate 10. Each of the filter bars FB1 to FB4 corresponds to an optical filtering wavelength. The filter bars are configured to selectively allow only specific optical wavelengths of light to pass through while blocking or reflecting others. The specific optical wavelengths can be selected from a range of O-band (1260 nm to 1360 nm). The prism 11 is disposed on the substrate 10 and configured to cover the plurality of filter bars FB1 to FB4. In an embodiment, the prism 11 can be a triangular piece of resin or other transparent material that refracts (or reflects) light. In the wavelength division device 100, a surface of the substrate 10 is etched to form the one or more grooves. After the plurality of filter bars FB1 to FB4 are coated, the plurality of filter bars FB1 to FB4 are bonded in