Fiber-based free-space optical system

Details Fiber-based free-space optical system Fiber-based free-space optical system

1989-10-06

1991-10-29

Kuntz, Curtis

Optical: systems and elements

Deflection using a moving element

Using a periodically moving element

2502031, 359159, 359172, 359180, 359189, H04B 1000

Patent

active

050621505

DESCRIPTION:

BRIEF SUMMARY
This application is a Continuation-In-Part of U.S. patent application Ser. No. 07/299,088 filed Jan. 23, 1989.
The present invention relates to fiber optics as applied to free-space coherent and incoherent optical systems.
The advantages of fiber optics in ground-based communication systems (whether telecommunications or radar, for example) is widely recognized. However, present space-borne optical systems (such as for communications and radar) typically rely on bulk optics, including mirrors and lenses rigidly mounted to an optical bench, to transfer light from optical sources to the exit aperture or from the entrance aperture to the optical receiver. Such designs are typically sensitive to thermal and mechanical perturbations, and may substantially impact upon the host payload and real estate utilization.


SUMMARY OF THE INVENTION

One aspect of the present invention includes a free-space optical system having an optical package having an interface with free-space and couplable to an acquisition, tracking and pointing network. The optical package includes an optical fiber connection device for interacting with a communication device; the two devices cooperate to transfer optical signals therebetween. The package is configured to transfer the signals under guidance of the network at the interface with free-space.
Various embodiments of this aspect may include any of the following features: The communication device may be a receiver and the optical package may include at least one nutation device. The connection device may include an optical fiber, and the optical package may act to transfer the optical signals into the fiber by nutation. The nutation device may include a beam steering mirror. The nutation device may include an active fiber coupler. The communication device may include a receiver and the optical package may further include a beam steering mirror, an active fiber coupler, and an acquisition, tracking and pointing network. At least the mirror or the coupler may be nutated. The nutation device may be a mechanical nutation device having a housing to which is affixed a flexure, the fiber guided by the flexure and terminating near an exposed end of the flexure, at least one actuator coupled between the flexure and the housing, or the nutation device may utilize an electro-optic or acousto-optic beam deflector in conjunction with a focusing lens to transfer signals into the fiber. The actuator may be electromagnetic, piezo-electric or electrostatic. The nutation device may be driven at a mechanical resonance. The nutation device may further include at least one positional sensor coupled between the housing and the flexure. The nutation device may further include at least two positional sensors, output signals of both sensors being applied to a position sensor amplifier section of the optical package, where the sensor output signals represent positional location of the fiber and which information is used to maximize coupling of the optical signals into the core of the fiber.
The communication device may be a receiver. The invention may further include a local oscillator and an optical fiber, the local oscillator providing a signal which is combined with the optical signal to perform coherent detection, and the fiber for coupling the receiver to the optical fiber connection device preferably being single-mode, polarization-preserving. A GaAlAs diode laser may be used as a local oscillator laser having an output power of 30 mW and operable at a wavelength of 0.86 micrometers. The local oscillator and optical signals may be combined in a fiber coupler. The combining coupler may be a 3 dB coupler. The coupler may be coupled to a double balanced receiver. The position sensor output may be fed back to a dither generator to compensate for changes in the response of the nutation device. The system may include a beam steering mirror. The position sensor output may be applied to a demodulator to demodulate the receiver output signal, the demodulator output being applied via a loop compensation network to c

REFERENCES:
patent: 3449587 (1969-06-01), Barnes
patent: 3941927 (1976-03-01), Russell
patent: 4621893 (1986-11-01), Lehmann
Giannaris, R. J. and Mooradian, G. C., "Shipboard Electro-Optic System, Integration," Proceedings of SPIE, vol. 103, pp. 120-125, 1977.
Johnson, M., "High-Precision Multiposition Singlemode Fiber Switch Using Magnetic Levidation," SPIE, vol. 734, pp. 154-158, 1987.
Schrittenlacher et al., Proc. of EFOC/LAN 88 Exposition, pp. 52-54, "Ultra-Low Loss Mechanical Fiber Switch".
Johnson, Proc. of EFOC/LAN 88 Exposition, pp. 219-222, "Optical Powering Techniques for Microstructure Fiber Sensors".
Tenuta, Interim Report of Rome Air Development Center, Jun., 1981, "Fiber Optic Receiver Preamplifier Design".
Newport Corporation, Sales Brochure for FX-1000 Microtranslator, 18235 Mt. Baldy Cir., P.O. Box 8020, Fountain Valley, Calif. 92728.
McElroy et al., "CO.sub.2 Laser Communication Systems for Near-Earth Space Applications", Proceedings of the IEEE, vol. 65, No. 2, Feb. 1977.
Bondurant et al., "An opto-Mechanical Subsystem for Space Based Coherent Optical Communication", SPIE, vol. 996, High Data Rate Atmospheric and Space Communications, 1988.
Kern et al., "Control of a Pointing, Acquisition, and Tracking Subsystem for Intersatellite Laser Links ISL.sub.2 ", SPIC, vol. 810 Optical Systems for Space Applications, 1987.
Yasukawa et al., "Research and Development Activities of Optical ISLs in Japan", International Journal of Satellite Communications, vol. 6, pp. 141-152, 1988.
Shikatani et al., "ETS-VI Experimental Optical Inter-Satellite Communication System", International Conference on Communications, Boston, Mass., Jun. 11-14, 1989.
Wittig et al., "Experimental and Preoperational Optical Intersatellite Links", SPIC, vol. 885, Free-Space Laser Communication Technologies, 1988.
Furch et al., "Optical Satellite Links for ESA's Space Missions", SPIC, vol. 810, Optical Systems for Space Applications, 1987.
Feldmann et al., "Airborne Laser Communications Scintillation Measurements and Model: A Comparison of Results", SPIC, vol. 885, Free-Space Laser Communication Technologies, 1988.
Johann et al., "A Free-Space Laser Communication Test-Bed Based on Coherent Diode-Pumped ND:YAG Laser Technology", presented at Free-Space Laser Communications Technologies-II, Los Angeles, Calif., Jan. 15-17, 1990.
Johann et al., "Diode Pumped Nd:Host Laser Transmitter for Intersatellite Optical Communications", presented at Free-Space Laser Communications Technologies-II, Los Angeles, Calif., Jan. 15-17, 1990.
Johann et al., "Design of a Diode-Pumped Nd:YAG Laser Communication System", presented at the 1991 SPIE Optical Fiber Communication Conference.
Carlson, "Technologies and Techniques for Lasercom Terminal Size, Weight, and Cost Reductions", presented at Free-Space Laser Communications Technologies-II, Los Angeles, Calif., Jan. 15-17, 1990.
Control Technics, Data Sheet for Piezo Series CTC-650, CTC-6151, CTC-6156, 22600-C Lambert Street, Suite 909, El Toro, Calif. 92630.
IntraAction Corp., Data Sheet for AOD-70 Acousto-Optic Deflector and ADM-70 Acousto-Optic Deflector-Modulator, 3719 Warren Avenue, Bellwood, Ill., 60104.
ConOptics Inc., Data Sheet for 310-Electro-Optic Beam Deflector, 67 Sandpit Road, Danbury, Conn., 06810.
x

Affiliated with

Also associated with

Rating

Fiber-based free-space optical system does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Fiber-based free-space optical system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fiber-based free-space optical system will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1404772