Flyin's fused couplers are used to split optical 

signals betweentwo fibers, or to combine optical 

signals from two fibers into one fiber. 

They are constructed by fusing and tapering two 

fibers together. This method provides a simple, 

rugged, and compact method of splitting and 

combining optical signals. Typical excess losses 

are as low as 0.2dB, while splitting ratios 

are accurate to within ±5 percent at the design wavelength. 

The devices are bidirectional, and offer low backreflection. The technique is best suited to singlemode and multimode couplers. 
Standard Wavelengths: 488nm, 514nm, 633nm, 830nm, 

1300-1350nm, and 1490-1550nm for single-mode fused 

couplers. Other wavelengths are available on request. 

Multimode couplers are broadband in nature. 
Their operating range is 400nm to 1600nm. 

Fiber Sizes: Singlemode: 3.5/125 for 488nm and 514nm 

couplers, 4/125 for 633nm, 5/125 for 830nm, and 9/125 

for 1300nm and 1550nm. 
Multimode: 50/125, 62.5/125 and 100/140 size fibers. 
Excess Loss: & lt; 0.3dB for 1300nm and 1550nm couplers. 

& lt; 0.5dB for 830nm couplers. & lt; 1.0dB        

for wavelengths between 480nm and 700nm. 
Directivity: 50dB or better. 
Splitting Ratio Accuracy: Within ±3% for 850nm, 

1300nm, and 1550nm wavelengths. Within ± 5% 

for wavelengths  between 480nm and 850nm. 

Temperature Range: -40°C to +85°C