Basic knowledge of light modules

Basic knowledge of light modules

1. Basic knowledge of light modules

1. Definition:

Light module: That is, light and transceiver module.

2. Structure:

The optical sending integrated module consists of optoelectronics, function circuits, and optical interfaces. The optoelectronic devices include launch and receiving.

The launch part is: Enter a certain code -rate telecommunications signal through the internal drive chip processing after processing the semiconductor laser (LD) or light emitting diode (LED) to emit the corresponding rate of the lighting signal. The output light signal power remains stable.

The receiving part is: the light signal input module with a certain code rate is converted from the light detection diode to the electrical signal. The electrical signal with the corresponding code rate after the front is placed in the front is placed, and the output signal is generally PECL level. At the same time, an alarm signal will be output after the input optical power is less than a certain value.

3. The parameters and meaning of the light module

There are many very important optoelectronic technology parameters, but for GBIC and SFP, the two hot insert modules, the most concerned when choosing is the following three parameters:

1) Central wavelength

There are currently three main types of unit nano (NM):

850nm (MM, multi -mode, low cost, but short transmission distance, generally only 500m can be transmitted); 1310nm (SM, single mode, large loss during transmission process, small scattered color, generally used for transmission within 40km);

1550nm (SM, single -mode, small loss during transmission process, large color scattered, generally used for long -range transmission above 40km, the farthest can be transmitted directly by the non -relay 120km);

2) Transmission rate

Bit (BIT), unit BPS transmitted data per second.

There are currently 4 types of commonly used: 155Mbps, 1.25Gbps, 2.5Gbps, 10Gbps, etc. The transmission rate is generally compatible with downward compatibility. Therefore, the 155M light module is also called the FE (100M) light module. The 1.25G light module is also called the GE (Gigabit) light module. This is the most applied module in the current light transmission equipment. In addition, its transmission rate in the fiber storage system (SAN) is 2Gbps, 4Gbps, and 8Gbps.

3) Transmission distance

The distance between the light signal does not need to be enlarged, the unit can be directly transmitted, the unit is kilometers (also known as the kilometer, KM). The light modules generally have the following specifications: 550m multi -mode, single -mode 15km, 40km, 80km, 120km, and so on.