2nm narrow-interval and high-isolation 50G PON (Passive Optical Network) application optical filter

Abstract

The utility model relates to a 2nm narrow-interval and high-isolation 50G PON (Passive Optical Network) application optical filter. The optical filter comprises an optical glass base material, one surface of the optical glass base material is plated with an interference film, and the purposes that the air incident angle is 8 degrees, the air incident angle is 5.3 degrees in glue, and the transmission wave band is 1290-1330 lt are achieved; 0.3 dB, and the reflected wave is 1284 to 1288 gt; and the performance requirement of 30dB is met.

Description

Technical Field

[0001] The utility model relates to the field of optical filters, and in particular to a 2nm narrow interval, high isolation 50G PON application filter. Background Art

[0002] To meet the needs of network evolution and development, 50G PON systems must support full-rate convergence across three generations and five modes on the same port. However, for operators, given the extensive deployment of existing assets such as EPON / GPON / 10GEPON / 10G GPON, protecting these investments, reusing them, and ensuring coexistence and compatibility across all three generations are key considerations. Uplink wavelengths are densely populated, including 1270±10nm, 1286±2nm, and 1310±20nm. The 1286±2nm and 1310±20nm bands have a narrow separation of only 2nm. Achieving high-isolation optical splitting requires innovative design and advanced control techniques, a major challenge for the industry.

[0003] The main challenge in splitting the 1286±2nm and 1310±20nm wavelength bands is achieving transmission in the 1290-1330nm band and isolation >30dB in the 1284-1288nm band. Current mainstream technologies can only achieve >10dB isolation in the 1284-1288nm band, or by narrowing the transmission band from 1290-1330nm to 1292-1330nm, thus reducing the splitting difficulty from 2nm spacing to 4nm. While reducing the isolation in the 1284-1288nm band or widening the transmission-reflection band spacing from 2nm to 4nm can ease filter design and manufacturing, it will significantly impact the overall 50G PON transmission performance. Utility Model Content

[0004] The purpose of this utility model is to provide a 2nm narrow-interval, high-isolation 50G PON application filter, which achieves the performance requirements of 8° incident angle in air, 5.3° in glue, transmission band 1290~1330<0.3dB, and reflection band 1284~1288>30dB.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A 2nm narrow-interval, high-isolation 50G PON application filter comprises an optical glass substrate, one side of which is coated with an interference film.

[0007] In a preferred design, the film system structure of the interference film is:

[0008] Glass / ((HL)^p(2H)^q(LH)^PL)^m / air

[0009] Wherein, H is the unit thickness of the high refractive index film, L is the unit thickness of the low refractive index film; P is [1, 5], q is [1, 6], and m is [26, +∞).

[0010] In a preferred design, the film system structure of the interference film is:

[0011] Glass / ((HL)^p H(2L)^q H(LH)^p L)^m / air

[0012] Wherein, H is the unit thickness of the high refractive index film, L is the unit thickness of the low refractive index film; P is [1, 5], q is [1, 6], and m is [26, +∞).

[0013] In a preferred design, the number of layers of the interference film is greater than 300.

[0014] In a preferred design, the thickness of the interference film is greater than 70 μm.

[0015] In a preferred design, the optical glass substrate is WMS-15 optical glass.

[0016] Through the above technical solution, the performance requirements of 8° incident angle in air, 5.3° in glue, transmission band 1290~1330<0.3dB, and reflection band 1284~1288>30dB are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of a 2nm narrow-interval, high-isolation 50G PON application filter provided by the present invention in one embodiment;

[0018] Figure 2 This is the transmittance curve of the 2nm narrow-interval, high-isolation 50G PON application filter provided by the utility model;

[0019] Figure 3 This is the reflective band transmittance curve of the 2nm narrow spacing, high isolation 50G PON application filter provided by the utility model;

[0020] Among them, Figures 2 to 3 In the transmittance curve, the ordinate represents transmittance and the abscissa represents wavelength.

[0021] 1-Optical glass substrate, 2-Interference film. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention will be described in further detail below with reference to the accompanying drawings.

[0023] According to a specific embodiment of the present disclosure, a large-angle short-wavelength wavelength division multiplexing filter is provided. Figures 1 to 3 One specific implementation method is shown.

[0024] See Figures 1 to 3 As shown, the 2nm narrow-interval, high-isolation 50G PON application filter includes an optical glass substrate 1, one side of which is coated with an interference film 2.

[0025] Through the above technical solution, the performance requirements of 8° incident angle in air, 5.3° in glue, transmission band 1290~1330<0.3dB, and reflection band 1284~1288>30dB are achieved.

[0026] It should be noted that the film stack of the interference film 2 adopts the following form, where each HL is a reflection pair, (2H)^q or (2L)^q is a spacer layer, L is a coupling layer, (HL)^p(2H)^q(LH)^PL or (HL)^p H(2L)^q H(LH)^p L is a Fabry-Perot cavity, and different spectroscopic effects are achieved by repeated stacking of Fabry-Perot cavities.

[0027] In one embodiment, the number of layers of the interference film 2 is greater than 300, and the thickness of the interference film 2 is greater than 70 μm.

[0028] The film structure of interference film 2 is:

[0029] Glass / ((HL)^p(2H)^q(LH)^PL)^m / air

[0030] Wherein, H is the unit thickness of the high refractive index film, L is the unit thickness of the low refractive index film; P is [1, 5], q is [1, 6], and m is [26, +∞).

[0031] Specifically, Ta2O5 is selected as the high refractive index thin film material, and SiO2 is selected as the low refractive index thin film material.

[0032] It should be noted that in the film structure, Glass refers to the optical glass substrate; air refers to air.

[0033] In another embodiment, the number of layers of the interference film 2 is greater than 300, and the thickness of the interference film 2 is greater than 70 μm. The film structure of the interference film 2 is:

[0034] Glass / ((HL)^p H(2L)^q H(LH)^p L)^m / air

[0035] Wherein, H is the unit thickness of the high refractive index film, L is the unit thickness of the low refractive index film; P is [1, 5], q is [1, 6], and m is [26, +∞).

[0036] Specifically, Ta2O5 is selected as the high refractive index thin film material, and SiO2 is selected as the low refractive index thin film material.

[0037] In one embodiment, the optical glass substrate 1 is WMS-15 optical glass, and WMS-15 optical glass is selected as the film layer carrier. High-precision magnetron sputtering technology is used for continuous film formation, supplemented by a high-precision light control algorithm, so that the regular layer of 1 / 4 optical wavelength stops at the extreme point (peak or trough). The coupling layer of each cavity and the stop point of the non-1 / 4 optical wavelength layer replaced by the equivalent matrix are not subject to the optical extreme method. The coating time is calculated by taking the average of the previous layers, and the coupling layer and the equivalent layer are stopped according to the coating time.

[0038] It should be noted that when a film stack with over 300 layers (m ≥ 26) is selected, the insertion loss and ripple in the transmission band increase dramatically. To effectively achieve the performance requirement of < 0.3 dB in the transmission band, the ripple in the transmission band needs to be compressed. Some H or L can be replaced with a variety of hypothetical materials M1, M2, ..., Mk, whose refractive indices are between H and L. By repeatedly adjusting the refractive indices of the materials M1, M2, ..., Mk, the ripple in the transmission band can be compressed to less than 0.3 dB. Through the concept of an equivalent matrix, each hypothetical material is converted into a symmetrical xH yL xH or xL yH xL form, so that the final film system can meet the optical performance requirements.

[0039] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

Claims

1. A 2nm narrow-interval, high-isolation 50G PON application filter, comprising an optical glass substrate (1), characterized in that: One side of the optical glass substrate (1) is coated with an interference film (2); The film system structure of the interference film (2) is: Glass / ((HL)^p(2H)^q(LH)^PL)^m / air or Glass / ((HL)^p H(2L)^q H(LH)^pL)^m / air Wherein, H is the unit thickness of the high refractive index film, L is the unit thickness of the low refractive index film; P is [1, 5], q is [1, 6], and m is [26, +∞).

2. The 2nm narrow-interval, high-isolation 50G PON application filter according to claim 1 is characterized in that: The number of layers of the interference film (2) is greater than 300.

3. The 2nm narrow-interval, high-isolation 50G PON application filter according to claim 1 is characterized in that: The thickness of the interference film (2) is greater than 70 μm.

4. The 2nm narrow-interval, high-isolation 50G PON application filter according to claim 1 is characterized in that: The optical glass substrate (1) is WMS-15 optical glass.

Images