Bi-Directional Fiberoptic Coupler Duncan Technologies, Inc., New Castle, CA

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Bi-Directional Fiberoptic CouplerDuncan
Technologies, Inc., New Castle, CA
Innovation Bi-Directional Fiberoptic Coupler -
DTI has developed a low cost bi-directional
fiberoptic coupler offering many benefits over
existing coupler solutions including enhanced
efficiency and reduced component count. The
bi-directional coupler can be used to
simultaneously couple two high-power diode lasers
into an optical fiber with no penalty in the
fiber size and virtually no added loss relative
to existing couplers. It can also be used to
couple light into an optical fiber and split off
a return signal for feedback sensing. This
feedback capability is critical in many
fiberoptic sensor applications. The coupler is
applicable to wavelength multiplexing in laser
systems for communication systems, medical
instruments, and specialized sensors. The
enhanced capabilities and reduced component costs
enable significant cost benefits in large-scale
production systems.
I Bi-Directional Fiberoptic Coupler
Diode Laser Manufacturers - The coupler can be
used to create diode laser packages that include
an integrated visible tracer beam, allowing
identification of the invisible high power diode
laser beam. This would enable a competitive
advantage for diode laser companies by providing
this functionality in an OEM product. The coupler
can also be used for summing the output of two
high power diode laser, either of the same
wavelength or two different wavelengths. Medical
Industrial Sensor Market - The coupler can be
used to couple light into an optical fiber and
split off a return signal for sensing. The
coupler, diode laser, and photodetector can be
integrated into a single compact hermetic
package. Optical Drive Optic - The coupler can
be used in optical disk drives in the read or
read/write head optical chain. The coupler
focuses the beam onto the disk surface and feeds
back the read signal. This single component can
replace a series of components that perform the
same function in current drives.
Accomplishments To date, the coupler has been
manufactured in small production runs. The
compnoent can easily be produced at low cost in
volumeat optics fabrication facilites. The cost
benefits and performance may be further enhanced
by adapting the design for the use of molded
plastic optics.Integration of the coupler into a
laser ignition system for hydrogen/oxygen
reaction control system thrusters on space
vehicles. The coupler was used to couple the
output of a high power diode laser source into a
fiber for delivery to the igniter, provide a
return signal to measure ignition target
temperature, and verify system operational
status. The system was fabricated and tested in
an altitude chamber using a laboratory version
of the hydrogen/oxygen thruster developed by
Rockwell to provide positional control for the
Space Station.

Commercialization The Bi-Directional
Fiber-Optic Coupler has one patent application
on file. Potential market sectors include
Fiberoptic Communications - The bi- directional
coupler can be used to couple output from two
different wavelength diode lasers into a single
optical fiber.This type of wavelength division
multiplexing (WDM) is useful in fiberoptic
network products. A key feature is virtually no
loss penalty in coupling two lasers into a
fiber. This enables WDM without significant loss
so the spacing between repeaters can remain the
same as in single wavelength systems.

Government/Science Applications The
Bi-Directional Fiberoptic Coupler is an integral
part of the
compact diode laser
package that is a part of DTI's Laser igniter

system. This system provides optical
ignition and ignition verification

of hydrogen/oxygen reaction control system
thrusters. The igniter
system has
potential for application on hydrogen/oxygen
engines for
reaction control system
thrusters and primary propulsion including

the SSME.
NASA Field Center Date of Update- April 20,
1998 Success Story 09-003
Points of Contact - NASA-Collin
Hieger-281-483-1803 - Flogiston- Brian
Park-512 894 0562 1993 SBIR Phase II NAS
NAS9-19316