Wireless communication system with high efficiency/high power optical source

• US 7,257,327 B2
• Filed: 08/30/2002
• Issued: 08/14/2007
• Est. Priority Date: 06/01/2000
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Small, James G.
• Primary Examiner(s): Phan; Hanh
• Application Number:
  US10/231,651
• Publication Number:
  US 20030016421A1
• Time in Patent Office: 1,810 Days
• Field of Search: 398118-134, 398/115, 398/116, 398/117, 398/135, 398/139, 398/136, 398/182, 398/183, 398/70, 398/71, 398/72, 398/66, 398/67, 398/68, 315/39.77, 315/39.73, 315/39.51, 315/39.65, 315/39.75
• US Class Current: 398/118
• CPC Class Codes: H01J 23/165 Manufacturing processes or apparatus therefore
• CPC Class Codes: H01J 23/213 Simultaneous tuning of more than one resonator, e.g. resonant cavities of a magnetron
• CPC Class Codes: H01J 23/22 Connections between resonators, e.g. strapping for connecting resonators of a magnetron
• CPC Class Codes: H01J 25/50 Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field with travelling wave not moving completely around the electron space H01J25/42; functioning with plural reflection or with reversed cyclotron action H01J25/62, H01J25/64
• CPC Class Codes: H04B 10/1125 using a single common optical path

Abstract

An optical communication system is provided which includes an optical signal transmitter which communicates high bandwidth, high power frequencies. The optical signal transmitter includes a high efficiency/high power optical source such as an optical magnetron or a phased array source of electromagnetic radiation, and a modulator element. The modulator element may be within a resonance cavity of the high efficiency/high power optical source (intra cavity) or external to the cavity (extra cavity). The modulator element serves to modulate output radiation of the high efficiency/high power optical source to produce a modulated high frequency optical signal which may be transmitted through the air. The optical signal transmitter is particularly useful in providing the last mile connection between cable service operators and end users.

Claims

1. An optical communication system, comprising:

a service provider which receives information signals and converts the information signals into optical signals having a frequency in the broad bandwidth frequency range;

an optical fiber network which receives the optical signals from the service provider; and

a high efficiency/high power optical source which receives the optical signals from the optical fiber network and transmits the optical signals through the air to an end user spaced from the high efficiency/high power optical source, the high efficiency/high power optical source comprising at least one of an optical magnetron or a phased array source of electromagnetic radiation, the optical magnetron or phased array source including a cathode, an anode spaced from the cathode, an interaction space between the anode and the cathode, and a magnetic field source, wherein the high efficiency/high power optical source includes an optical magnetron and one or more output waveguides and output antennas connected to the optical magnetron to direct the output signals toward one or more end users.

2. An optical communication system, comprising:

a service provider which receives information signals and converts the information signals into optical signals having a frequency in the broad bandwidth frequency range;

an optical fiber network which receives the optical signals from the service provider; and

a high efficiency/high power optical source which receives the optical signals from the optical fiber network and transmits the optical signals through the air to an end user spaced from the high efficiency/high power optical source, the high efficiency/high power optical source comprising at least one of an optical magnetron or a phased array source of electromagnetic radiation, the optical magnetron or phased array source including a cathode, an anode spaced from the cathode, an interaction space between the anode and the cathode, and a magnetic field source, wherein the high efficiency/high power optical source includes a phased array source of electromagnetic radiation and one or more output waveguides and output antennas connected to the phased array source of electromagnetic radiation to direct the output signals toward one or more end users.

3. An optical communication system, comprising:

an optical signal communication station including a first optical signal receiver and a first high efficiency/high power optical source;

one or more end users spaced from the optical signal communication station, each end user including a second optical signal receiver and a second high efficiency/high power optical source;

wherein the first high efficiency/high power optical source transmits through the air first optical signals having a frequency in the broad bandwidth frequency range and one or more of the second optical signal receivers of the respective end users detects the first optical signals, and the second high efficiency/high power optical source transmits through the air second optical signals having a frequency in the broad bandwidth frequency range and the first optical signal receiver of the optical signal communication station detects the second optical signals, the first high efficiency/high power optical source comprising at least one of an optical magnetron or a phased array source of electromagnetic radiation, the optical magnetron or phased array source including a cathode, an anode spaced from the cathode, an interaction space between the anode and the cathode, and a magnetic field source, further comprising a modulator element disposed within a resonant cavity of an optical resonator for modulating a high frequency optical signal of the high efficiency/high power optical source.

4. The optical communication system of claim 3, wherein the modulator element includes a material having an electro optic effect to change the dielectric constant of the modulator element according to a modulated voltage applied to the modulator element.

5. The optical communication system of claim 4, wherein the material of the modulator element is lithium niobate.

6. The optical communication system of claim 3, further including a voltage generator for applying a voltage to the modulator element.

7. The optical communication system of claim 3, wherein the inner circumference of the optical resonator defines a cavity wall and wherein the outer circumference of the modulator element abuts the cavity wall.

8. The optical communication system of claim 3, wherein the optical resonator has a plurality of radially extending output ports through which the modulated optical signals are transmitted, and further including a plurality of output waveguides and respective output antennas connected to and extending radially outwardly from the optical resonator at the respective output ports which direct the modulated optical signals toward a plurality of directions.

9. The optical communication system of claim 3, further including a mixer element disposed relative to the modulator element to receive modulated high frequency signals therefrom, wherein the mixer element compares one or more of the output frequency and output phase of the modulated high frequency optical signal to a reference frequency standard to detect drifting in the output frequency or output phase.

10. The optical communication system of claim 3, further including a mode locking device which applies a periodic input voltage to data input terminals connected to the modulator element to lock a mode of the optical resonator.

11. The optical communication system of claim 10, wherein the frequency spacing between allowed modes of the optical resonator is defined by the equation f=Nc/2L, wherein N is the mode number, c is the speed of light and L is the radial distance between outer circumference of the anode and the inner circumference of the optical resonator.

12. The optical communication system of claim 11, wherein the optical resonator is mode locked when the period of the modulating voltage equals the period of the mode frequency spacing.

13. The optical communication system of claim 3, wherein the anode includes a plurality of interdigitated electrodes equally spaced apart circumferentially about a circle coaxially aligned with the cathode.

14. The optical communication system of claim 3, wherein the high efficiency/high power optical source includes an optical magnetron.

15. The optical communication system of claim 3, wherein the high efficiency/high power optical source includes a phased array source of electromagnetic radiation.

16. An optical signal transmitter, comprising:

a high efficiency/high power optical source which produces high frequency optical signals, the high efficiency/high power optical source including an optical resonator having a plurality of radially extending output ports through which the optical signals are transmitted;

a plurality of output waveguides and respective output antennas connected to and extending radially outwardly from the optical resonator at the respective output ports; and

a plurality of high frequency modulator elements, each of which modulates the high frequency optical signal with an information signal to produce a modulated high frequency optical signal and which directs the modulated optical signals toward a plurality of respective directions.

17. The optical signal transmitter of claim 16, wherein each modulator element includes a material having an electro optic effect to change the dielectric constant of the modulator element according to a modulated voltage applied to the modulator element.

18. The optical signal transmitter of claim 16, wherein each modulator element modulates the high frequency optical signal independently of other modulator elements.

19. The optical signal transmitter of claim 16, wherein for an output frequency of 250 Ghz, the modulation rate is about 100 gigabits per second in each output waveguide.

20. The optical signal transmitter of claim 16, wherein the high efficiency/high power optical source includes an anode and a cathode, and wherein the anode includes a plurality of interdigitated electrodes equally spaced apart circumferentially about a circle coaxially aligned with the cathode.

21. The optical signal transmitter of claim 16, wherein the high efficiency/high power optical source includes an optical magnetron.

22. The optical signal transmitter of claim 16, wherein the high efficiency/high power optical source includes a phased array source of electromagnetic radiation.

23. The optical signal transmitter of claim 16, wherein the output antenna includes an output horn antenna.