Wavelength division multiplexing architecture based on integrated bragg and adiabatic TE0 mode add/drop filter
A method and apparatus are provided. The method includes receiving, at a TE 0 mode add/drop filter, a TE 0 mode optical signal having a first wavelength and a second wavelength, and transmitting, from the TE 0 mode add/drop filter, the TE 0 mode optical signal having the first wavelength and the second wavelength towards a Bragg grating, without converting the TE 0 mode optical signal having the first wavelength and the second wavelength to another mode. The method further includes receiving, at the TE 0 mode add/drop filter, a reflected TE 1 mode optical signal having the first wavelength from the Bragg grating, and transmitting, from the TE 0 mode add/drop filter, the reflected TE 1 mode optical signal having the first wavelength towards a photodetector, without converting the reflected TE 1 mode optical signal having the first wavelength to another mode.
1. A method comprising:
receiving, at a TE 0 mode add/drop filter, a TE 0 mode optical signal having a first wavelength and a second wavelength;
transmitting, from the TE 0 mode add/drop filter, the TE 0 mode optical signal having the first wavelength and the second wavelength towards a Bragg grating, without converting the TE 0 mode optical signal having the first wavelength and the second wavelength to another mode;
receiving, at the TE 0 mode add/drop filter, a reflected TE 1 mode optical signal having the first wavelength from the Bragg grating; and
transmitting, from the TE 0 mode add/drop filter, the reflected TE 1 mode optical signal having the first wavelength towards a photodetector, without converting the reflected TE 1 mode optical signal having the first wavelength to another mode,
wherein the TE 0 mode add/drop filter comprises:
a bus waveguide;
a lower waveguide disposed on a first side of the bus waveguide; and
an upper waveguide disposed on a second side of the bus waveguide opposite to the first side of the bus waveguide,
wherein the upper waveguide follows at least a portion of a path of the lower waveguide, and opposing longitudinal edges of both the lower waveguide and the upper waveguide, along the at least a portion of the path, are located between longitudinal edges of the bus waveguide.
2. The method of claim 1 , wherein the TE 0 mode add/drop filter is an adiabatic TE 0 mode add/drop filter.
3. The method of claim 1 , further comprising:
receiving the TE 0 mode optical signal having the first wavelength and the second wavelength on the lower waveguide; and
transmitting the TE 0 mode optical signal having the first wavelength and the second wavelength towards the Bragg grating on the bus waveguide disposed above the lower waveguide.
4. The method of claim 3 , further comprising:
receiving the reflected TE 1 mode optical signal having the first wavelength from the Bragg grating on the bus waveguide; and
transmitting the reflected TE 1 mode optical signal having the first wavelength towards the photodetector on the bus waveguide.
5. The method of claim 4 , wherein the lower waveguide is a single-mode waveguide comprised of silicon and the bus waveguide is a multimode waveguide comprised of silicon nitride.
6. The method of claim 5 , further comprising:
establishing, using the upper waveguide, a pseudo-symmetry about a longitudinal axis of the bus waveguide to prevent TE 1 -TM 0 mode hybridization of optical signals that traverse the bus waveguide.
7. The method of claim 1 , further comprising:
mode multiplexing, by the TE 0 mode add/drop filter, the TE 0 mode optical signal having the first wavelength and the second wavelength with the reflected TE 1 mode optical signal having the first wavelength.
8. The method of claim 1 , further comprising:
receiving, at a TE 1 →TE 0 mode converter, the reflected TE 1 mode optical signal having the first wavelength from the TE 0 mode add/drop filter;
converting, by the TE 1 →TE 0 mode converter, the reflected TE 1 mode optical signal having the first wavelength to a converted TE 0 mode optical signal having the first wavelength; and
transmitting, from the TE 1 →TE 0 mode converter, the converted TE 0 mode optical signal having the first wavelength to the photodetector.
9. The method of claim 1 , further comprising:
transmitting, from the Bragg grating, a non-reflected TE 0 mode optical signal having the second wavelength towards a second TE 0 mode add/drop filter.
10. An apparatus comprising:
a TE 0 mode add/drop filter; and
a Bragg grating connected with the TE 0 mode add/drop filter;
wherein the TE 0 mode add/drop filter is configured to:
receive a TE 0 mode optical signal having a first wavelength and a second wavelength;
transmit the TE 0 mode optical signal having the first wavelength and the second wavelength towards the Bragg grating, without converting the TE 0 mode optical signal having the first wavelength and the second wavelength to another mode;
receive a reflected TE 1 mode optical signal having the first wavelength from the Bragg grating; and
transmit the reflected TE 1 mode optical signal having the first wavelength towards a photodetector, without converting the reflected TE 1 mode optical signal having the first wavelength to another mode,
wherein the TE 0 mode add/drop filter comprises:
a bus waveguide;
a lower waveguide disposed on a first side of the bus waveguide; and
an upper waveguide disposed on a second side of the bus waveguide opposite to the first side of the bus waveguide,
wherein the upper waveguide follows at least a portion of a path of the lower waveguide, and opposing longitudinal edges of both the lower waveguide and the upper waveguide, along the at least a portion of the path, are located between longitudinal edges of the bus waveguide.
11. The apparatus of claim 10 , wherein the TE 0 mode add/drop filter is an adiabatic TE 0 mode add/drop filter.
12. The apparatus of claim 10 , wherein the TE 0 mode add/drop filter is configured to:
receive the TE 0 mode optical signal having the first wavelength and the second wavelength on the lower waveguide; and
transmit the TE 0 mode optical signal having the first wavelength and the second wavelength towards the Bragg grating on the bus waveguide disposed above the lower waveguide.
13. The apparatus of claim 12 , wherein the TE 0 mode add/drop filter is configured to:
receive the reflected TE 1 mode optical signal having the first wavelength from the Bragg grating on the bus waveguide; and
transmit the reflected TE 1 mode optical signal having the first wavelength towards the photodetector on the bus waveguide.
14. The apparatus of claim 13 , wherein the lower waveguide is a single-mode waveguide comprised of silicon and the bus waveguide is a multimode waveguide comprised of silicon nitride.
15. The apparatus of claim 14 , wherein the TE 0 mode add/drop filter further establishes, using the upper waveguide, a pseudo-symmetry about a longitudinal axis of the bus waveguide to prevent TE 1 -TM 0 mode hybridization of optical signals that traverse the bus waveguide.
16. The apparatus of claim 10 , wherein the TE 0 mode add/drop filter is configured to mode multiplex the TE 0 mode optical signal having the first wavelength and the second wavelength with the reflected TE 1 mode optical signal having the first wavelength.
17. The apparatus of claim 12 , further comprising:
a TE 1 →TE 0 mode converter configured to:
receive the reflected TE 1 mode optical signal having the first wavelength from the TE 0 mode add/drop filter;
convert the reflected TE 1 mode optical signal having the first wavelength to a converted TE 0 mode optical signal having the first wavelength; and
transmit the converted TE 0 mode optical signal having the first wavelength to the photodetector.
18. The apparatus of claim 10 , wherein the Bragg grating is configured to transmit a non-reflected TE0 mode optical signal having the second wavelength towards a second TE0 add/drop filter.
19. A method comprising:
receiving a TE 0 mode optical signal having a first wavelength and a second wavelength;
transmitting the TE 0 mode optical signal having the first wavelength and the second wavelength towards a Bragg grating, without converting the TE 0 mode optical signal having the first wavelength and the second wavelength to another mode;
receiving a reflected TE 1 mode optical signal having the first wavelength from the Bragg grating; and
transmitting the reflected TE 1 mode optical signal having the first wavelength towards a photodetector, without converting the reflected TE 1 mode optical signal having the first wavelength to another mode,
wherein receiving the TE 0 mode optical signal having a first wavelength and a second wavelength comprises receiving the TE 0 mode optical signal having a first wavelength and a second wavelength at a TE 0 mode add/drop filter, which comprises:
a bus waveguide;
a lower waveguide disposed on a first side of the bus waveguide; and
an upper waveguide disposed on a second side of the bus waveguide opposite to the first side of the bus waveguide,
wherein the upper waveguide follows at least a portion of a path of the lower waveguide, and opposing longitudinal edges of both the lower waveguide and the upper waveguide, along the at least a portion of the path, are located between longitudinal edges of the bus waveguide.
20. The method of claim 19 , wherein receiving the TE 0 mode optical signal, transmitting the TE 0 mode optical signal, receiving reflected TE 1 mode optical signal, and transmitting the reflected TE 1 mode optical signal are performed by the TE 0 mode add/drop filter.