Measurement and analysis of optical communication test parameters
Optical communication is a technology that uses optical signals to transmit information in optical fibres or other media, which has the advantages of high transmission rate, large bandwidth and strong anti-interference. In order to evaluate the performance of optical communication system or optical module, some optical communication test parameters need to be measured and analysed, which include transmit optical power, receive sensitivity, extinction ratio, bit error rate, eye diagram and so on. This paper will briefly introduce the meaning, measurement method and analysis significance of these parameters.
Transmitted optical power, transmitted optical power, refers to the power of the optical signal emitted by the light source to reach the receiving end after a certain distance, usually expressed in decibels milliwatts (dBm). Transmitted optical power reflects the output capacity of the light source, but also an important factor affecting the system transmission distance and signal-to-noise ratio. The larger the transmitter optical power, the stronger the output capability of the system, the longer the transmission distance and the higher the signal-to-noise ratio; the smaller the transmitter optical power, the weaker the output capability of the system, the closer the transmission distance and the lower the signal-to-noise ratio. The measurement method of transmit optical power is very simple, only need to use an optical power meter connected to the output of the light source.
Receiver sensitivity, RECEIVER SENSITIVITY, refers to the minimum input optical power at the receiving end that can correctly identify the data bits, and is usually also expressed in decibels milliwatts (dBm). Receiver sensitivity reflects the detection capability of the receiver, and is also an important factor affecting the system BER and fault tolerance. The higher the reception sensitivity, the stronger the detection capability of the receiving end, the lower the BER and the better the fault tolerance; the lower the reception sensitivity, the weaker the detection capability of the receiving end, the higher the BER and the worse the fault tolerance. The measurement method of receiving sensitivity requires a BER meter and an adjustable optical attenuator. Firstly, connect the BER meter to the transmitter and receiver, and then adjust the optical attenuator so that the input optical power is gradually reduced until it reaches the BER threshold set by the BER meter (usually 10^-9^ or 10^-12^), and at this time, the input optical power is the reception sensitivity.
Extinction ratio, extinction ratio, refers to the ratio of the time power when the signal is sent at high level and low level, usually expressed in decibels (dB). Extinction ratio reflects the modulation quality of the optical signal and is an important parameter of the optical module. The size of the extinction ratio determines the quality of the communication signal. The larger the extinction ratio is, the better the logic discrimination rate will be at the receiver end; the smaller the extinction ratio is, the more susceptible the signal is to interference, and the system BER will increase. The measurement of extinction ratio requires the use of an eye chart meter or an optical modulation analyser. An eye chart can visualise the difference between high and low levels and calculate the extinction ratio; an optical modulation analyser can more accurately measure the average power at high and low levels and calculate the extinction ratio.
An eye diagram, eye diagram, refers to a graphic that displays an optical signal overlaid on an oscilloscope, which resembles the shape of an eye, hence the name. Eye diagram is a visual method to analyse the performance of optical communication system, which can reflect the signal quality, amplitude, width, jitter, distortion and other characteristics. The more open the eye diagram is, the better the signal quality and the lower the BER; the more closed the eye diagram is, the worse the signal quality and the higher the BER. The measurement of the eye diagram requires the use of an eye chart meter or an oscilloscope. The eye chart meter can directly display the eye chart and provide some analysis functions, such as measuring the eye height, eye width, cross point, etc.; the oscilloscope can display the eye chart by setting the trigger mode and scanning speed, and provide some measurement functions, such as measuring the amplitude, width, and jitter.
Communication test parameters are an important basis for evaluating the performance of optical communication systems or optical modules, and they reflect different system characteristics and problems. By measuring and analysing these parameters, the reliability and efficiency of optical communication systems can be effectively improved.
Optical communication is a technology that uses optical signals to transmit information in optical fibres or other media, which has the advantages of high transmission rate, large bandwidth and strong anti-interference. In order to evaluate the performance of optical communication system or optical module, some optical communication test parameters need to be measured and analysed, which include transmit optical power, receive sensitivity, extinction ratio, bit error rate, eye diagram and so on. This paper will briefly introduce the meaning, measurement method and analysis significance of these parameters.
Transmitted optical power, transmitted optical power, refers to the power of the optical signal emitted by the light source to reach the receiving end after a certain distance, usually expressed in decibels milliwatts (dBm). Transmitted optical power reflects the output capacity of the light source, but also an important factor affecting the system transmission distance and signal-to-noise ratio. The larger the transmitter optical power, the stronger the output capability of the system, the longer the transmission distance and the higher the signal-to-noise ratio; the smaller the transmitter optical power, the weaker the output capability of the system, the closer the transmission distance and the lower the signal-to-noise ratio. The measurement method of transmit optical power is very simple, only need to use an optical power meter connected to the output of the light source.
Receiver sensitivity, RECEIVER SENSITIVITY, refers to the minimum input optical power at the receiving end that can correctly identify the data bits, and is usually also expressed in decibels milliwatts (dBm). Receiver sensitivity reflects the detection capability of the receiver, and is also an important factor affecting the system BER and fault tolerance. The higher the reception sensitivity, the stronger the detection capability of the receiving end, the lower the BER and the better the fault tolerance; the lower the reception sensitivity, the weaker the detection capability of the receiving end, the higher the BER and the worse the fault tolerance. The measurement method of receiving sensitivity requires a BER meter and an adjustable optical attenuator. Firstly, connect the BER meter to the transmitter and receiver, and then adjust the optical attenuator so that the input optical power is gradually reduced until it reaches the BER threshold set by the BER meter (usually 10^-9^ or 10^-12^), and at this time, the input optical power is the reception sensitivity.
Extinction ratio, extinction ratio, refers to the ratio of the time power when the signal is sent at high level and low level, usually expressed in decibels (dB). Extinction ratio reflects the modulation quality of the optical signal and is an important parameter of the optical module. The size of the extinction ratio determines the quality of the communication signal. The larger the extinction ratio is, the better the logic discrimination rate will be at the receiver end; the smaller the extinction ratio is, the more susceptible the signal is to interference, and the system BER will increase. The measurement of extinction ratio requires the use of an eye chart meter or an optical modulation analyser. An eye chart can visualise the difference between high and low levels and calculate the extinction ratio; an optical modulation analyser can more accurately measure the average power at high and low levels and calculate the extinction ratio.
An eye diagram, eye diagram, refers to a graphic that displays an optical signal overlaid on an oscilloscope, which resembles the shape of an eye, hence the name. Eye diagram is a visual method to analyse the performance of optical communication system, which can reflect the signal quality, amplitude, width, jitter, distortion and other characteristics. The more open the eye diagram is, the better the signal quality and the lower the BER; the more closed the eye diagram is, the worse the signal quality and the higher the BER. The measurement of the eye diagram requires the use of an eye chart meter or an oscilloscope. The eye chart meter can directly display the eye chart and provide some analysis functions, such as measuring the eye height, eye width, cross point, etc.; the oscilloscope can display the eye chart by setting the trigger mode and scanning speed, and provide some measurement functions, such as measuring the amplitude, width, and jitter.
Communication test parameters are an important basis for evaluating the performance of optical communication systems or optical modules, and they reflect different system characteristics and problems. By measuring and analysing these parameters, the reliability and efficiency of optical communication systems can be effectively improved.