LED Characteristics: Linearity

Study Notes

LED Characteristics:

Linearity of LED Current vs. Optical Power: The current through an LED is directly proportional to the optical power emitted.
Linear Region: The region where the LED current and optical power have a linear relationship, typically up to a certain current threshold (e.g., 10-20 mA).
Non-Linear Region: Beyond the linear region, the optical power increases at a slower rate than the current, due to internal heating and other non-ideal effects.

Photodetector Characteristics:

Linearity of Photocurrent vs. Incident Optical Power: The photocurrent generated by a photodetector is directly proportional to the incident optical power, within a certain range.
Linear Dynamic Range: The range of incident optical powers over which the photodetector response remains linear, typically specified in decibels (dB).
Non-Linear Effects: At high incident optical powers, photodetectors may exhibit non-linear effects, such as saturation, compression, or distortion, which can limit their performance.

The current through an LED is directly proportional to the optical power emitted, exhibiting a linear relationship.
The linear region of an LED is typically up to a certain current threshold, such as 10-20 mA, where the current and optical power have a direct proportional relationship.
Beyond the linear region, the optical power increases at a slower rate than the current due to internal heating and other non-ideal effects, resulting in a non-linear region.

The photocurrent generated by a photodetector is directly proportional to the incident optical power within a certain range, demonstrating linearity.
The linear dynamic range of a photodetector is the range of incident optical powers over which the response remains linear, typically specified in decibels (dB).
At high incident optical powers, photodetectors may exhibit non-linear effects, such as saturation, compression, or distortion, which can limit their performance.

LEDs require linearity to maintain a proportional relationship between input current and output light intensity.
Linearity is crucial in applications such as optical communication systems where accurate light intensity control is necessary.
Linear LEDs have a linear I-L (current-light) curve, whereas non-linear LEDs have a non-linear I-L curve.

Photodetectors require linearity to maintain a proportional relationship between input light intensity and output electrical signal.
Linearity is essential in applications such as optical sensing and imaging systems where accurate light intensity measurement is necessary.
Linear photodetectors have a linear L-V (light-voltage) curve, whereas non-linear photodetectors have a non-linear L-V curve.
Factors affecting photodetector linearity include saturation, which occurs at high light intensities, and electrical noise.