SM FBT Coupler Inspection Standard

1.Aim and Scope
This standard applies to the following products:
1X2 and 2X2 SM FBT Coupler and cascaded SM splitter with 1X2 and 2X2

2.Test instruments:
Optical light source, optical power meter and Polarization controller

3.Raw material: alcohol, fiber cleaning wipes, etc.

4.Safety: be careful of fiber into skin

5.Sampling solution
Manufacturing department: 100% inspection
Quality department:
1)execute standard GB2828, IL=II, AQL=0.04
2)Other products: 10% sampling inspection

6.Inspection items:
6.1: Central wavelength insertion loss
If there were N outputs and splitting ratio of one output was R.
6.1.1.Grade P
Max. Insertion loss at all polarization states ≤-
10.3×lg(R)+0.415×lgN, no connector;
10.3×lg(R)+0.415×lgN+0.2, input or output is with connector;
10.3×lg(R)+0.415×lgN+0.4, input and output are with connector.
Min. Insertion loss at all polarization states ≥-9.7×lg(R)
Equal splitting ratio: uniformity at central wavelength≤-0.6×lg(R)

6.1.2: Grade A
Max. Insertion loss at all polarization states ≤-
10.5×lg(R)+0.581×lgN, no connector;
10.5×lg(R)+0.581×lgN+0.2, input or output is with connector;
10.5×lg(R)+0.581×lgN+0.4, input and output are with connector.
Min. Insertion loss at all polarization states ≥-9.5×lg(R)
Equal splitting ratio: uniformity at central wavelength≤-lg(R)

6.1.3: Grade B
Max. Insertion loss at all polarization states ≤-
10.7×lg(R)+0.677×lgN, no connector;
10.7×lg(R)+0.677581×lgN+0.2, input or output is with connector;
10.7×lg(R)+0.677×lgN+0.4, input and output are with connector.
Min. Insertion loss at all polarization states ≥-9.4×lg(R)
Equal splitting ratio: uniformity at central wavelength≤-1.2×lg(R)
Remark: The insertion loss and uniformity of FBT Couplers at Grade P, A and B is at 1310nm and 1550nm. For 1490nm wavelength, the insertion loss adds 0.15dB for every cascading and n*0.15dB for n cascading; the uniformity adds 0.15dB for every cascading and n*0.15dB for n cascading.

6.2.Max. PDL

Model 1×2 1×3 1×4 1×5 1×6 1×7 1×8 1×9 1×10 1×12 1×16 1×24 1×32
20nm Grade P 0.10
Grade A 0.15 0.20 0.20 0.30 0.30 0.30 0.30 0.40 0.40 0.40 0.40 0.50 0.50
Grade B 0.20 0.30 0.30 0.45 0.45 0.45 0.45 0.60 0.60 0.60 0.60 0.75 0.75
40nm wideband Grade P 0.10
Grade A 0.15 0.30 0.30 0.45 0.45 0.45 0.45 0.60 0.60 0.60 0.60 0.75 0.75
Grade B 0.20 0.40 0.40 0.60 0.60 0.60 0.60 0.80 0.80 0.80 0.80 1.00 1.00

6.3.Max. Excess loss

Model 1×2 1×3 1×4 1×5 1×6 1×7 1×8 1×9 1×10 1×12 1×16 1×24 1×32
Grade P 0.15 0.24 0.30 0.35 0.39 0.42 0.45 0.48 0.50 0.54 0.60 0.69 0.75
Grade A 0.20 0.32 0.40 0.46 0.52 0.56 0.60 0.63 0.66 0.72 0.80 0.92 1.00
Grade B 0.25 0.40 0.50 0.58 0.65 0.70 0.75 0.79 0.83 0.90 1.00 1.15 1.25

Note:
a. The above excess loss applies to the splitter without connectors.
b. For the splitter with connector at input or output, excess loss adds 0.20dB.
c. For the splitter with connector at input and output, excess loss adds 0.40dB.

6.4. Directivity and return loss
Normally, the directivity and return loss are not tested.
If required, they will be tested according to the clients’ requirements.

6.5. Uniformity
For the equal splitting splitters, figure out the uniformity values according to the testing results.

7. Testing methods
Two options: ratio of power/db or db/insertion loss.