New optoelectronic devices for the Near and Mid-Infrared spectral range open completely new possibilities for portable sensors creation. Using infrared LED-PD optopairs allows developing an instrument that is smaller, less expensive and energy-saving.

LED Operation Modes

LEDs offer numerous benefits due to possibility of different operation modes. Optical parameters of light emitting diodes strongly depend on the operation regime that you choose.

There are two main ways to drive LEDs: quasi continuous-wave mode (QCW) and pulse mode.

QCW means that an LED is switched on only for certain time intervals, which are short enough to reduce thermal effects significantly, but still long enough that the LED process is close to steady state. We recommend using pulse modes with duty cycle 50% or 25% to receive maximum average power. These modes provide signal modulation at certain frequency and allow obtaining higher output intensity than in case of using hard CW (continuous wave) mode. Therefore hard CW is not recommended.

Pulse mode with short pulse time (less than 50 ms) helps obtaining the maximum peak power.