Optical Modules and Fiber Connector Applications

This article briefly introduces the knowledge of optical modules and optical fiber connectors

1. Module classification

1. Classified by rate: 100base (100M), 1000base (gigabit), 10GE for Ethernet applications; 155M, 622M, 2.5G, 10G for SDH applications

2. According to package classification: 1x9, SFF, SFP, GBIC, XENPAK, XFP

1x9 package---welding optical module, the general speed is not higher than gigabit, and SC interface is mostly used

SFF package---soldering small package optical module, the general speed is not higher than gigabit, and LC interface is mostly used

GBIC package---hot-swappable Gigabit interface optical module, using SC interface

SFP package---hot-swappable small package module, currently the highest rate can reach 4G, mostly using LC interface

XENPAK package---used in 10 Gigabit Ethernet, using SC interface

XFP package---10G optical module, can be used in 10 Gigabit Ethernet, mostly using LC interface

3. Classification by laser type: LED, VCSEL, FPLD, DFBLD

4. According to the emission wavelength classification: 850nm, 1310nm, 1550nm, etc.

5. According to the plugging method: non-hot pluggable 1x9, SFF, hot pluggable GBIC, SFP, XENPAK, XFP

2. Classification of optical fiber connectors

1. The optical fiber connector is to install the connector on both ends of a section of optical fiber, which is used for optical wiring.

2. Classification according to fiber type: single-mode fiber connector, generally G.642 fiber, inner diameter 9um, outer diameter 125um; multimode fiber connector, one is G.651 fiber, inner diameter 50um, outer diameter 125um, the other The species is an inner diameter of 62.5um and an outer diameter of 125um.

3. According to the connector classification of optical fiber connectors: FC, SC, ST, LC, MU, MTRJ, etc.

FC type (ferrule connector)---The external reinforcement adopts metal sleeve, and the fastening method is turnbuckle. Commonly known as round head.

SC type---the shell adopts the molding process and is made of molded glass fiber plastic, which is rectangular, the pin is made of precision ceramics, the coupling sleeve is a metal slotted sleeve structure, and the fastening method adopts the plug-in type. Rotation is required. Commonly known as square head.

LC type---the outer diameter of the casing is 1.25mm, usually half of the outer diameter of the FC-SC and ST casing is 2.5mm, which improves the application density of the connector.

4. The performance of optical fiber connectors mainly includes optical performance, interchangeability, mechanical performance, environmental performance and life. The most important of these are insertion loss and return loss.

3. Main parameters of optical module

1. Optical module transmission rate: 100M, Gigabit, 10GE, etc.

2. Transmitting optical power and receiving sensitivity of an optical module: Transmitting optical power refers to the light intensity of the transmitting end, and receiving sensitivity refers to the detectable light intensity. These two important parameters affect the transmission distance. The distance that an optical module can transmit is limited mainly by loss and dispersion.

3. The 10GE optical module follows the 802.3ae standard. The transmission distance is related to the type of optical fiber and the optical performance of the optical module.

4.The saturated optical power value refers to the maximum optical power that can be detected by the receiving end of the optical module, generally -3dBm. When the received optical power is greater than the saturated optical power, bit errors will occur.