Broadband polarization beam splitter/combiner based on gradient waveguide directional coupler
A broadband polarization beam splitter/combiner based on a gradient waveguide directional coupler, comprises a gradient waveguide directional coupler, a beam combining end ( 1 ), a curved waveguide ( 5 ), a TE mode end ( 6 ) and a TM mode end ( 7 ). The coupler consists of a straight end gradient waveguide ( 2 ) and a serial end gradient waveguide ( 3 ). The trend of change of the gradient waveguide ( 2 ) is opposite to the gradient waveguide ( 3 ), and a gap is provided between the gradient waveguide ( 2 ) and the gradient waveguide ( 3 ). The beam combining end ( 1 ) is connected with one end of the gradient waveguide ( 2 ), the other end of the gradient waveguide ( 2 ) is connected with one end of the curved waveguide ( 5 ), the other end of the curved waveguide ( 5 ) is connected with the TE end ( 6 ), and the waveguide ( 3 ) is connected with the TM end ( 7 ).
1. A broadband polarization beam splitter/combiner based on gradient waveguide directional coupler, configured to split a light into a light of a transverse electric mode TE mode and a light of a transverse magnetic mode TM mode, or to combine a light of a transverse electric mode TE mode and a light of a transverse magnetic mode TM mode into a light, consists of a gradient waveguide directional coupler, a beam combining end ( 1 ), a curved waveguide ( 5 ), a transverse electric mode TE end ( 6 ) and a transverse magnetic mode TM end ( 7 ), the gradient waveguide directional coupler consists of a straight end gradient waveguide ( 2 ) and a serial end gradient waveguide ( 3 ), the trend of change of the straight end gradient waveguide ( 2 ) is opposite to that of the serial end gradient waveguide ( 3 ), and a gap ( 4 ) is provided between the straight end gradient waveguide ( 2 ) and the serial end gradient waveguide ( 3 ), the beam combining end ( 1 ) is connected with one end of the straight end gradient waveguide ( 2 ), the other end of the straight end gradient waveguide ( 2 ) is connected with one end of the curved waveguide ( 5 ), the other end of the curved waveguide ( 5 ) is connected with the transverse electric mode TE end ( 6 ), and the serial end gradient waveguide ( 3 ) is connected with the transverse magnetic mode TM end ( 7 ).
2. The broadband polarization beam splitter/combiner of claim 1 , wherein when the broadband polarization beam splitter/combiner is used as a beam splitter, a light is incident from the beam combining end ( 1 ), a light of TE mode exits from the transverse electric mode TE end ( 6 ), and a light of TM mode exits from the transverse magnetic mode TM end ( 7 ).
3. The broadband polarization beam splitter/combiner of claim 1 , wherein when the broadband polarization beam splitter/combiner is used as a beam combiner, a light of TE mode is incident from the transverse electric mode TE end ( 6 ), a light of TM mode is incident from the transverse magnetic mode TM end ( 7 ), and a light resulting from combining the two polarized light exits from the beam combining end ( 1 ).
4. The broadband polarization beam splitter/combiner of claim 1 , wherein the width of the straight end gradient waveguide ( 2 ) is tapered, and the width of the serial end gradient waveguide ( 3 ) is increased.
5. The broadband polarization beam splitter/combiner of claim 4 , wherein the width of the straight end gradient waveguide ( 2 ) is tapered from [0.5, 1] μm to [0.3, 0.45] μm, the width of the serial end gradient waveguide ( 3 ) is increased from [0.3, 0.45] μm to [0.5, 1] μm, and the gap is provided between the straight end gradient waveguide ( 2 ) and the serial end gradient waveguide ( 3 ).
6. The broadband polarization beam of claim 5 , wherein the width of the straight end gradient waveguide ( 2 ) is tapered from [0.6, 0.9] μm to [0.35, 0.45] μm, the width of the serial end gradient waveguide ( 3 ) is increased from [0.35, 0.45] μm to [0.6, 0.9] μm, and the gap is provided between the straight end gradient waveguide ( 2 ) and the serial end gradient waveguide ( 3 ).
7. The broadband polarization beam of claim 1 , wherein the width of the straight end gradient waveguide ( 2 ) is increased, and the width of the serial end gradient waveguide ( 3 ) is tapered.
8. The broadband polarization beam of claim 7 , wherein the width of the straight end gradient waveguide ( 2 ) is increased from [0.3, 0.45] μm to [0.5, 1] μm, the width of the serial end gradient waveguide ( 3 ) is tapered from [0.5, 1] μm to [0.3, 0.45] and the gap is provided between the straight end gradient waveguide ( 2 ) and the serial end gradient waveguide ( 3 ).
9. The broadband polarization beam of claim 8 , wherein the width of the straight end gradient waveguide ( 2 ) is increased from [0.35, 0.45] μm to [0.6, 0.9] μm, the width of the serial end gradient waveguide ( 3 ) is tapered from [0.6, 0.9] μm to [0.35, 0.45] μm, and the gap is provided between the straight end gradient waveguide ( 2 ) and the serial end gradient waveguide ( 3 ).