Transcript The New Passively Biased IFOG

The New Passively Biased IFOG
A New Approach to IFOG by TeraEx
• Eliminating the phase modulator and its driver electronics
• Utilizing an innovative technique to passively bias the fiber coil
• Using non PM or standard fibers and components to reduce radiation
sensitivity and cost
• Simplifying optics and electronics
A New Type of IFOG with Passively Biased Coil
Electronic Circuit
Depolarizer
SLED
Splitter
Splitter
Sensor
Coil
Detector
A/D
AMP
Driver
Passively
Biased
DSP
Digital or Analog Signal Output
TeraEx IFOG makes use of property of
depolarized light and further eliminates
the problematic phase modulator and
its associated driver electronics with a
new passively biased optical coil
residing in its quadrature point.
Quadrature
point
Intensity
2
y ( x)
6
1.26810
 10
x
10
f
Advantages Of The New IFOG
Advantages of the New IFOG (no PM Fiber and Component)
With TeraEx proprietary depolarized source the IFOG does not require PM fiber and components.
This enables use of non radiation sensitive standard and low bending radius fiber for low cost
and small coil size gyro’s respectively. Unlike PM, fiber length can be scaled up to many 10’s
of km if needed.
Electronic Circuit
Depolarizer
SLED
Splitter
Detector
A/D
AMP
DSP
Digital or Analog Signal Output
Splitter
Sensor
Coil
Advantages of a Passive Type Bias
In a vibration prone environment, the passive coil does not induce voltage noises
or stress/thermal effects associated with active phase modulation. In addition
electronics becomes simpler with no need for a modulator driver with its associated
drifts.
Electronic Circuit
Depolarizer
SLED
Splitter
Splitter
Detector
A/D
AMP
No induced noise voltage
DSP
Digital or Analog Signal Output
Sensor
Coil
Advantages of a Passive Type Bias….
Length of fiber or size of fiber coil sensor can be freely chosen further simplifying
the design of both optics and electronics. Miniature remote sensor coil with diameter
of 0.5” or smaller is possible.
Electronic Circuit
Depolarizer
SLED
Splitter
Detector
A/D
AMP
DSP
Digital or Analog Signal Output
Splitter
Sensor
Size
Advantages of a Passive Type Bias….
A tethered and passive remote sensor
head can be placed anywhere in
normal or harsh environment
Electronics can be placed in a controlled
and safe environment far from the sensor head
Sensor
Coil
A passive single mode optical patch cord from meters
to kilometers long connects the main module to its
sensor head without any concern for noise pickups
Advantages of a Passive Type Bias….
The sensor head can also be connectorized
with fiber optic bulkhead such as FC/PC
Advantages of a Passive Type Bias (3-D)
A tethered and passive remote sensor head for
sensing three axes of rotation simultaneously
A passive single mode optical patch cord from meters
to kilometers long connects the main module to its
sensor head without any concern for noise pickups
In summary
Advantages of TeraEx IFOG with Passive Bias are;
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No need for phase modulator and associated driver electronics
No associated optical or electrical modulator drift
No associated vibration noise generation (no PZT)
No radiation or vacuum charge ups and drifts (no Lithium Niobate material)
No fiber longevity concerns (PZT related)
• Unlike PM, fiber length can be scaled up to many 10’s of km if needed.
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Miniature remote sensor coil with diameter of 0.5” or smaller possible
No associated noise pickups by tethered cable
Any desired length tethered optical cable between remote sensor coil and its
electronics
No need for PM fiber and components and their associated radiation
darkening
Simpler optical and electronic circuitry
New Applications
Passive Bias Technology with Remote Sensor Head
With passive bias technology new applications would be opening up for IFOG. These
applications may require sophisticated electronics in protected environment to meet
high performance while necessitating miniature scale gyro probes for compact system
integration capable of withstanding harsh conditions such as;
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High / low temperatures
Oil drilling
Wing of an airplane
Under water cavern and deep sea scuba diving
Satellite
Condensed spaces