What are the technical standards for fiber optic connector inspection?

1.Fiber optic connector appearance inspection.

Inspection items	Inspection standards		Remarks
Integrity	All parts are complete and consistent with the corresponding design and manufacturing requirements. The processing quality meets the requirements of relevant technical documents, and the test data, labels, and barcodes are correct.
Appearance	All components must be smooth, clean, and free of dirt, burrs, scratches, and cracks. They should have a bright, consistent color. The components should be firmly and evenly joined. The connectors should insert and pull out of the adapters smoothly and easily, and the clips should be strong, resilient, and function properly. The optical cable should be smooth and bright, free of impurities and damage, with clear printing, and the color should match the product requirements.
Optical cable length	Length (L)	Tolerance	Can be modified as per customer requirements.
	L≤0.5m	+0.01/-0m
	0.5m＜L＜5m	+0.05/-0m
	5m≤L≤10m	+0.1/-0m
	L＞10m	+0.2/-0m
Identification	Apply a serial number label or a marking ring to the rear end of the strain relief boot, or leave it blank, as per order requirements.
Packaging	The packaging box should include the following: product name, model, production batch, production date, company’s registered trademark, executive standard number, environmental protection logo, and a product manual. The packaging itself must be complete and free of defects such as damage, crushing, deformation, or dirt.		Can be modified as per customer requirements.

2. Assembly Performance

2.1 Ferrule: Normal protrusion length, good elasticity, and a clear chamfer. The surface must be free of any dirt, defects, or other imperfections.

2.2 Loose Parts: Each loose part must fit well with the adapter without loosening. They should have good mechanical performance and mobility. The surfaces must be free of any dirt, defects, damage, or cracks. The color should match product requirements, with no chromatic aberration within the same batch.

2.3 Crimping: The crimping and fixation of the optical cable jacket and Kevlar fibers must be secure. The crimped metal parts should have a regular indentation, free of damage, bending, or improper squeezing of the cable.

3. End-Face Standard

Inspect according to Appendix 1, “Fiber Optic Connector End-Face Inspection Specification.”

4. Insertion and Return Loss Technical Standards

Connector Model	FC,SC,LC,ST,MU,E2000,D4,DIN
Mode	SM			MM
End-face specification	PC	UPC	APC	PC
IL(dB)	≤0.3	≤0.2	≤0.3	≤0.3
RL(dB)	≥45	≥50	≥60	≥35
Other models	MT-RJ、MPO
IL(dB)	≤0.7	/	≤0.7	≤0.5
RL(dB)	≥30	/	≥50	≥25

5. End-Face Geometry (3D) Standards.

Item	PC、UPC				APC
	SC,FC,ST,E2000,D4,DIN		LC,MU		SC,FC,E2000	LC,MU
	SM	MM	SM	MM	SM	MM
Radius of Curvature (mm)	10-25		7-20		5-12
Apex Offset	≤50				≤30
Fiber protrusion/recession (nm)	±100
Angle Deviation (°)	0				8±0.3
Key Angle Deviation (°)	0				±0.5
Fiber Diameter (µm)	123-135

6. Qualified Product Identification

Qualified product identification includes: serial number (each product has a unique one, consisting of the production plan number plus a sequential number), model number, barcode label (optional, based on customer requirements), product manual (optional), 3D report (optional), environmental protection label (optional), and insertion/return loss test data, etc.

7. Product Packaging

7.1 Basic Product Packaging: The fiber optic connector should be coiled into a circle with a diameter of 15-18 cm. The two ends of the connector should be secured with a cable tie symmetrically to the middle of the coil. Depending on the product model, the tie method can be a figure-eight (“8”) or a straight line (“1”) to prevent it from coming loose without leaving marks on the cable. For 0.9 mm cables, a snake-shaped tube is used for binding. Special models should be handled according to the corresponding “Packaging Operation Guide.” The bound connector should be placed head-down into its corresponding, pre-labeled packaging bag. The bag mouth should be sealed, and as much air as possible should be removed without deforming the connector.

7.2 Final Packaging: After basic packaging, the products are put into a shipping box in integer units. The inside of the box is partitioned with cardboard, bubble wrap, pearl cotton, or other anti-crushing protective materials. Special models should be handled according to the corresponding “Packaging Operation Guide.” After applying a packing list and other product labels to the outside, the box is sealed and placed in the designated finished goods area.

8. Technical Standards for Each Component

8.1 Ferrule:

8.1.1 The product complies with the following standards:

• YDT 1198-2002 “Technical Requirements for Fiber Optic Connector Ferrule”
• Telcordia GR-326-CORE

8.1.2 Detailed technical requirements can be found in Appendix 2, “Conventional Ferrule Technical Standards.”

8.2 Optical Fiber/Cable:

8.2.1 The product complies with the following standards:

• YDT 1258.1-2003 “Indoor Optical Cables Part 1: General”
• YDT 1258.2-2003 “Indoor Optical Cables Part 2: Simplex Cables”
• YDT 1258.3-2003 “Indoor Optical Cables Part 3: Duplex Cables”
• YDT 1258.4-2005 “Indoor Optical Cables Part 4: Multi-core Cables”
• YDT 1258.5-2005 “Indoor Optical Cables Part 5: Ribbon Fiber Cables”
• YDT 1258.3-2009 “Indoor Optical Cables Part 3: Simplex and Duplex Cables for Premises Wiring”
• YDT 908-2000 “Method for Naming Optical Cable Models”

8.2.2 Performance, dimensions, materials, color, and environmental protection conform to relevant national industry standards. The color of products within the same batch and model must be consistent.

8.3 Connector:

8.3.1 Product performance indicators comply with the following national standards:

• GBT 12507.1-2000 “Fiber Optic Connector Part 1: Generic Specification”
• GBT 12507.2-1997 “Fiber Optic Cable Connector Part 2: Sectional Specification for F-SMA Type”
• YDT 1272.1-2003 “Fiber Optic Patch Cords Part 1: LC Type”
• YDT 1272.2-2005 “Fiber Optic Patch Cords Part 2: MT-RJ Type”
• YDT 1272.3-2005 “Fiber Optic Patch Cords Part 3: SC Type”
• YDT 1272.4-2007 “Fiber Optic Patch Cords Part 4: FC Type”
• YDT 1272.5-2009 “Fiber Optic Patch Cords Part 5: MPO Type”
• YD987-1998 “Technical Specification for ST/PC Type Single-mode Fiber Optic Patch Cords”
• YDT 2152-2010 “Reliability Requirements and Test Methods for Fiber Optic Patch Cords”

8.3.2 Connector Loose Parts Color Chart:

Fiber Optic Connector Models	SM					MM
	Structure	Outer Housing	Strain Relief Boot	Dust Cap	Heat Shrink Tube	Structure	Outer Housing	Strain Relief Boot	Dust Cap	Heat Shrink Tube
FC/PC	SX,DX	Metal	Black	Colorless	/	SX,DX	Metal	Black	Colorless	/
FC/APC	SX,DX	Metal	Green	Green	/	SX,DX	/
SC/PC	SX,DX	Blue	Blue	Colorless	/	SX,DX	Beige	Beige	Colorless	/
SC/APC	SX,DX	Green	Green	Green	/	SX,DX	/
LC/PC	SX,DX	Blue	White	White	Yellow，White	SX,DX	BlueBeige	White	White	Yellow，White
LC/APC	SX,DX	Green	Green	Green	Yellow，White	SX,DX	/
E2000/UPC	SX,DX	Blue	Blue	/	/	SX,DX	Blue	Brown	/	/
E2000/APC	SX,DX	Green	Green	/	/	SX,DX	/
MU/PC	SX,DX	Brown	Blue	Black	/	SX,DX	Brown	Blue	Black	/
MU/APC	SX,DX	Green	Green	Green	/		/
ST/PC	SX,DX	Metal	Black	Colorless	/	SX,DX	Metal	Black	Colorless	/
MT-RJ	multi-core	Black	Black	Colorless	/	multi-core	Black	Black	Colorless	/
MPO/PC	multi-core	Yellow	Black	Black	/	multi-core	Beige	Black	Black	/
MPO/APC	multi-core	Green	Black	Green	/	multi-core	/
D4	SX,DX	Metal	White	Colorless	/	SX,DX	Metal	White	Colorless	/
DIN	SX,DX	Metal	White	White	/	SX,DX	Metal	White	White	/

Appendix I: Fiber Optic Connector End-Face Inspection Specification

1.Inspection Equipment: 400X end-face inspection microscope with a monitor.

2.End-Face Requirements:

Regional range	Description of defect	Grade A End-Face Inspection Standard
Within a ⌀50 µm diameter	Scratches,Spots,Bubbles,Black spots,Cracks,Dirt	No negative defects are allowed.
Within a diameter of 50-125 µm.
O-ring	Black spots/blocks, unevenness, spots, cracks, and dirt. The size must not exceed 1/4 of the fiber core and the width must be no greater than 1 µm.
Ceramic end-face part (visible area outside the O-ring).	Scratches,Spots,Bubbles,Black spots,Cracks,Dirt
Mode field core area.	No cracks, scratches, patches, or shadows. Light transmission is good, with a clear light spot.

3.Fiber Optic End-Face Diagram

Appendix II: Conventional Ferrule Technical Standards

I. Product Technical Standards

1. Ferrule Material: Made of Zirconium Dioxide (ZrO2​) powder, an opaque milky white color that complies with the RoHS standard.
2. Chemical Composition:

ZrO2(Wt%)	≈94.3
Y2O3(Wt%)	5.40±0.20
A12O2(Wt%)	0.25±0.05
SiO2(Wt%)	≤0.03
Na2O(Wt%)	≤0.01
Fe2O3(Wt%)	≤0.01

II. Ferrule Specification Types and Dimension Requirements

1.Conventional Ferrule Specification Classification (Model Specification Classification)

SC Type	SC/SM/PC
	SC/MM/PC
	SC/SM/APC
LC Type	LC/SM
	LC/MM

2. Technical Requirements:

SC Type
Item	Unit	Specification
		SM	MM
Out Diameter	mm	⌀2.4990 ±0.0005
Concentricity	mm	≤0.0014	≤0.004
Inner Diameter	mm	⌀0.125~0.126	⌀0.127~0.130
Appearance of Endface	/	Roundness and appearance are qualified.
Length	mm	10.50±0.05

LC Type
Item	Unit	Specification
		SM	MM
Out Diameter	mm	⌀1.2490 ±0.0005
Concentricity	mm	≤0.0014	≤0.004
Inner Diameter	mm	⌀0.125~0.126	⌀0.127~0.130
Appearance of Endface	/	Roundness and appearance are qualified.
Length	mm	10.50±0.05
Diameter of Endface	mm	⌀0.60±0.15/-0
Degree of front chamfer	°	35°±2.5°

3.Tail-end Specification

Optical Fiber Ferrule Specifications	Tail-end Specifications	Protrusion length	Withdrawal Force
SC/PC	Stainless steel SUS303 or nickel-plated copper, slot width 1.5 mm	7.95±0.05/0	＞50N
SC/APC	Stainless steel SUS303 or nickel-plated copper, slot width 1.35 mm	8.10±0.05/0
LC/PC	Stainless steel SUS303 or nickel-plated copper	4.95±0.05/0
LC/APC		5.10±0.05/0
ST/PC		7.95±0.05/0