Extended transit time array photodetector combiner (ETT-APC)
High-performance ultra-wideband Phased Array Antennas (PAA) are disclosed, having unique capabilities, enabled through photonic integrated circuits and novel optical architectures. Unique capabilities for PAA systems are enabled by photonic integration and ultra-low-loss waveguides. Novel aspects include optical multiplexing combining wavelength division multiplexing and/or a novel extension to array photodetectors, providing the capability to combine many RF photonic signals with very low loss. Architectures include tunable optical up-conversion and down-conversion systems, moving a chosen frequency band between baseband and a high RF frequency band with high dynamic range. Simultaneous multi-channel RF beamforming is achieved through power combining/splitting of optical signals.
1. An Extended Transit Time Array Photodetector Combiner (ETT-APC), comprising:
an array of Y photodetectors, where Y≥2, that receives a series of Y optical signals, one optical signal to each one of the Y photodetectors,
wherein a bandwidth of the ETT-APC comprises a combination of a transit time bandwidth of each individual one of the Y photodetectors and a parasitic bandwidth of the array of Y photodetectors,
wherein a depletion width of each of the Y photodetectors is increased to any value up to 4 micrometers,
wherein the bandwidth of the ETT-APC is increased by reducing the transit time bandwidth of each of the Y photodetectors to any value down to 14 GHz.
2. The device of claim 1 , wherein all of the Y photodetectors are waveguide photodetectors having individual waveguide inputs.
3. The device of claim 1 , wherein all of the Y photodetectors are Modified Uni-Traveling Carrier (MUTC) photodetectors.
4. The device of claim 1 , wherein each of the array of Y photodetectors is physically separate.
5. Two ETT-APCs according to claim 1 , wherein each of said two ETT-APCs are arranged as a differential pair through wiring.
6. The device of claim 1 , the device forming one group of a Group Array Photodetector Combiner (GAPC) device, said GAPC device including:
X groups with K photodetectors total, where K=Y*X, where X≥2,
wherein each group of X groups is electrically connected to a next group of X groups by inductance L,
wherein a capacitance C and inductors produce an artificial transmission line that includes each of the X groups, having an impedance Z, using values of the inductance L for the inductors within the artificial transmission line and values of the inductance L/2 for the inductors at ends of the artificial transmission line, where Z=sqrt(L/C).
7. The device of claim 6 , wherein all of the K photodetectors are waveguide photodetectors having individual waveguide inputs.
8. The device of claim 6 , wherein all of the K photodetectors are Modified Uni-Traveling Carrier (MUTC) photodetectors.
9. The device of claim 6 , wherein an electrical output from the GAPC is a voltage across a load resistor at the end of the artificial transmission line.
10. The device of claim 6 , wherein each of the array of K photodetectors is physically separate.
11. The device of claim 10 , wherein the K optical signals to each of the K photodetectors is comprised of multiple optical signals of different wavelengths, wherein there is an absence of any wavelength overlap between each of the multiple optical signals.
12. The device of claim 6 , further comprising a second GAPC, wherein each of said two GAPC devices are arranged as a differential pair through wiring.
13. The device of claim 1 , wherein the depletion width is 4 micrometers and the transit time bandwidth of each of the Y photodetectors is 14 GHz.
14. The device of claim 1 , wherein the depletion width is 2 micrometers and the transit time bandwidth of each of the Y photodetectors is 29 GHz.