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What is the Optical module？

Optical module is an accessory for photoelectric conversion, one of the core devices in optical fiber communication, and an optoelectronic device that realizes photoelectric conversion and electro-optical conversion functions.

The optical module is a conversion device for photoelectric signals and needs to be plugged into the device for use. Both electrical signals and optical signals are magnetic wave signals. The transmission range of electrical signals is limited, while optical signals can transmit faster and farther. However, some current devices recognition electrical signals, so there is a photoelectric conversion module. The optical module is used to convert the electrical signal into an optical signal at the sending end, and after transmission through the optical fiber, the receiving end converts the optical signal into an electrical signal.

To be precise, optical module is a general term for several types of modules, Including: optical Transmitter module, Optical receiver module, Optical transceiver module, and Optical transponder module.

The key parameters of several optical modules are introduced below. The key technical indicators of the optical module mainly include: Transmit optical power, Receive optical power, Overload optical power, Maximum receiving sensitivity, and Extinction ratio.

1.Transmit optical power: refers to optical power output by the light source at the transmitting end of optical module under normal working conditions. It can be understood as the intensity of light, and the unit is W or mW or dBm. where W or mW is a linear unit and dBm is a logarithmic unit. In communication, we usually use dBm to represent optical power, and 0dBm optical power corresponds to 1mW.

2.Received optical power: refers to the average optical power range that the receiving end component can receive under the condition of a certain bit error rate (BER=10-12) of the optical module. The upper limit is the overload optical power, and the lower limit is the maximum receiving sensitivity.

3.Overload optical power: also known as saturated optical power, It refers to the maximum input average optical power that the receiving end component can receive when a certain bit error rate (BER=10-12) is maintained at a certain transmission rate, unit: dBm .

4.Maximum value of receiving sensitivity: refers to the minimum average input optical power that can be received by the component at the receiving end when a certain transmission rate and a certain bit error rate (BER=10-12) are maintained, unit: dBm.

5.Extinction Ratio: (EXT) is one of the important parameters used to measure the quality of optical modules. It refers to the ratio of the optical power P1 when the laser transmits all "1" codes to the optical power P0 when all "0" codes are transmitted under full modulation conditions, And the unit is dB. The extinction ratio reflects the relative amplitude of the "1" level and the "0" level of the optical signal. The factors affecting the extinction ratio in the optical module are the bias current (Bias) and the modulation current (Mod). The extinction ratio can be regarded as the value of EXT=Bias/Mod. The value of the extinction ratio is not the better the optical module, but the better the optical module whose extinction ratio meets the IEEE 802.3 standard.

Above is all content of this article. As a professional optical module manufacturer, Sanland Technology is committed to high-quality optical module products. For more information on optical module products, Please follow the official website of Sanland Technology. Thank you for your support!