2015年10月5日星期一

a new generation of advanced Fiber optic gyro devices from FOGPhotonics

Fiber-optic gyroscope (FOG) Technology From FOGPhotonics,inc

a new generation of advanced Fiber optic gyro devices


Introduction: The fiber optic gyroscope (FOG) is a solid state rotation sensor with no moving parts.  The rotation sensing part of a  FOG consists of a very simple interferometer.  The interferometer includes a beam splitter and a single length of fiber formed into a loop.  The beam splitter splits a single input light wave into two light waves.  The two light waves are inserted into opposite ends of the fiber.  The two waves propagate through each other and arrive back at the beam splitter and are combined.  The optical power of the combined waves is then converted to an electrical signal and used to measure rate of rotation perpendicular to the loop of fiber.  The sensitivity to rotation is increased by increasing the size of the fiber loop.  Low-loss optical fiber provides an opportunity to increase the FOG sensitivity in a reasonably sized package by winding the fiber into a coil.  In this way we add sensitivity with each turn of fiber.

Sagnac Effect: The fundamental effect upon which a FOG is based was demonstrated by Georges Sagnac in 1913. Sagnac set about to disprove the theory of relativity, and to support his argument he built an interferometer that now bears his name. The original Sagnac interferometer used mirrors and a beamsplitter. Such an interferometer (enclosing about one square mile) was used to measure the rotation rate of the Earth in 1925 to support the theory of relativity. Today a FOG can be made with an optical fiber and a directional coupler. Light is split by the directional coupler, enters the two ends of a single optical fiber formed into a coil, passes through itself; arrives back at the directional coupler and is combined as it emerges from the interferometer. In the non-rotating example (below left), the portion of light depicted as blue travels exactly the same path as the portion of light depicted as red and the two waves emerge from the interferometer at precisely the same time, i.e. in phase. In the rotating example (below right) the portion of light depicted as blue travels a longer path than the portion of light depicted as red and the blue light portion emerges delayed relative to the red light portion. The emerging light waves are not in phase. This phase difference is proportional to the rotation rate and is manifest as a change in optical power at the detector. For more information click here.
Principle of Sagnac interferometer showing source light split to propagate in opposite directions through a fiber loop, pass through itself, and re-emerge after being combined.  While the split light portions emerge at precisely the same time in the non rotating case (left) the blue light travels further than the red light portion in the rotating example (right).  The resulting phase difference is proportional to the rotation rate.






PRINCIPLE OF SAGNAC INTERFEROMETER SHOWING SOURCE LIGHT SPLIT TO PROPAGATE IN OPPOSITE DIRECTIONS THROUGH A FIBER LOOP, PASS THROUGH ITSELF, AND RE-EMERGE AFTER BEING COMBINED.  WHILE THE SPLIT LIGHT PORTIONS EMERGE AT PRECISELY THE SAME TIME IN THE NON ROTATING CASE (LEFT) THE BLUE LIGHT TRAVELS FURTHER THAN THE RED LIGHT PORTION IN THE ROTATING EXAMPLE (RIGHT).  THE RESULTING PHASE DIFFERENCE IS PROPORTIONAL TO THE ROTATION RATE.

Multiaxis devices:  Each FOG measures a single axis of rotation.  Three FOGs are required to completely determine the three dimensional rotation rate vector. A three dimensional rotation rate vector is measured in an inertial measurement unit (IMU), an attitude and heading reference system  (AHRS), an inertial navigation system (INS) and many gyro compasses.

How to select your system fiber optic gyro or ring laser gyro?

How to choose select gyro?
Inertial sensors
INS = Inertial Navigation System
IMU = Inertial Measurement Unit
Gyros and acceleration sensors
Based on conservation of momentum/inertia or changes of the path length (optical gyros)no external support needed, work everywhere under the known physical laws

Gyro performance
Classification according to bias drift
Rate grade 10 10000 deg/h
Tactical grade 0,01 10 deg/h
Navigation grade <0,01 deg/h
Mechanical, optical (fog, laser ring), MEMS (tuning fork, vibrating ring)
Dynamic area: few Hz 500Hz

Active Ring-laser Gyro
Active optical resonator
Resonator is a laser itself (active)
If gyro is rotated counter-clock wise direction, the counter-clock wise beam is travelling slightly longer than the opposite beam
The change in the path length is proportional to the rotation rate
In very small rotation rates there is a dead-band because of frequency lock-in
Seismic application of optical rotational sensors

         Application areas and performances of the RLG and FOG gyroscopes
                Contemporary inertial sensors qualification

2014年10月6日星期一

Fiber Coil Winding Service

Fiber Coil Winding Service--Idealphotonics Inc

COMPANY INFO

LINKED

Fiber Coil Winding Service
Category: Fiber coil  Publish Time: 2014-07-18 03:08 

Fiber Coil Winding Service
Price : $0.00
Delivery Fee : $0.00
Quantity :
 Part NO. :  FCWS-series
 Datasheet :  
 Availability :  4-6 Weeks




Fiber Coil Winding Service
1st .Capablities
With a 5 year legacy of winding all types of precision optical fiber coils, Idealphotonics has the coil winding business unit with a team of highly experienced scientists, engineers, and winders, together capable of winding the best in optical fiber coils in accordance with customers' requirements. Cost effective and fast winding systems allow Idealphotonics to provide a complete range of products, from simple delay lines and payout spools to strategic quadrupole gyro coils of several kilometers in length.We provide optical fibers and then put them on the most appropriate stands whatever the material they are made of is (copper, aluminium, plastic…). We can also work without stand and realize optical fibers crowns. Otherwise, a wide range of optical fibers types (single-mode, multi-mode, PM, from UV to IR) and dimensions are available, a well as coating materials (polymer, polyimide…).
Finally, we are at your disposal in order to meet your expectations and to solve yours problems as regards fiber optic coil winding, size and components integration among others.  
Our optical fibers spools lead to numerous applications in the fields of optical sensors, delay lines and fiber optic launch cables in particular.
2nd .Feathures
● Using the quadruple method without paper in the process;
● High crosstalk and low attenuation;
● It can be customized with different precious requirements;
● The crosstalk is little change in full temperature condition ;
● Flexible installation.
3
rd .Application
● FOG
● FOCT
● Optoelectronic sensor system
4
th .Ordering information
a.Coil structure parameters
specifications

Fiber core diameter
From 13 mm to 500 mm
Fiber external diameter
From 30 µm to 600 µm
Fiber length
Up to 50 km
Turn number per layer
From 8 to 250 turn
Fiber tension
From 20 g to 2 kg
Coating material
Polymer, polyimide, others
Spool stand
Copper, aluminium, plastic, others
b.Coil properlities
Items
Parameter
Unit
Coil inner diamete
1310/1550
nm
Crosstalk
-18
dB
Attenuation
1.0
dB/km
All kinds of fiber coil


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Fiber Coil Winding Service
1st .Capablities
With a 5 year legacy of winding all types of precision optical fiber coils, Idealphotonics has the coil winding business unit with a team of highly experienced scientists, engineers, and winders, together capable of winding the best in optical fiber coils in accordance with customers' requirements. Cost effective and fast winding systems allow Idealphotonics to provide a complete range of products, from simple delay lines and payout spools to strategic quadrupole gyro coils of several kilometers in length.We provide optical fibers and then put them on the most appropriate stands whatever the material they are made of is (copper, aluminium, plastic…). We can also work without stand and realize optical fibers crowns. Otherwise, a wide range of optical fibers types (single-mode, multi-mode, PM, from UV to IR) and dimensions are available, a well as coating materials (polymer, polyimide…).
Finally, we are at your disposal in order to meet your expectations and to solve yours problems as regards fiber optic coil winding, size and components integration among others.  
Our optical fibers spools lead to numerous applications in the fields of optical sensors, delay lines and fiber optic launch cables in particular.
2nd .Feathures
● Using the quadruple method without paper in the process;
● High crosstalk and low attenuation;
● It can be customized with different precious requirements;
● The crosstalk is little change in full temperature condition ;
● Flexible installation.
3
rd .Application
● FOG
● FOCT
● Optoelectronic sensor system
4
th .Ordering information
a.Coil structure parameters
specifications

Fiber core diameter
From 13 mm to 500 mm
Fiber external diameter
From 30 µm to 600 µm
Fiber length
Up to 50 km
Turn number per layer
From 8 to 250 turn
Fiber tension
From 20 g to 2 kg
Coating material
Polymer, polyimide, others
Spool stand
Copper, aluminium, plastic, others
b.Coil properlities
Items
Parameter
Unit
Coil inner diamete
1310/1550
nm
Crosstalk
-18
dB
Attenuation
1.0
dB/km
All kinds of fiber coil