The pulsed laser diodes (PLDs) are a type of laser that emits pulses. Under pulsed operation, these LDs have a high peak output. There are several varieties, each with a different peak output power and emission width. These can be used for various distance measurements, such as laser radar, security hazard monitoring, and so on.
How does it work?
Electrically, a laser diode is a PIN diode. The laser diode’s active zone lies in the intrinsic region, with electrons and holes carriers pumped in from the N and P regions, respectively. While early diode laser experiments used basic P-N diodes, today’s lasers all use a double-hetero-structure design. The carriers and photons are restricted to enhance their chances of recombination and light emission. A laser diode, unlike a typical diode, is built to recombine all carriers in the I region and produce light.
Although this method explains the essential operation of a laser diode, it is ineffective to operate as a device. Hence, a continuous pulse driver is required to assist in the application for various uses.
Pulsed laser diode driver
A pulsed laser diode driver is a voltage-controlled constant current source that produces a repeating set of current pulses at a fixed output level at user-defined time intervals. Their laser output is measured in amplitude and temporal units. This type of driver has time units in the tens of picoseconds, pulse widths in the nanosecond and microsecond range, and frequencies ranging from single shot to 500 MHz.
Features of pulsed laser diodes (PLDs)
The product qualification test plan is based on the AEC-Q102 requirements for stress testing discrete optoelectronic semiconductors in automotive applications based on failure mechanisms.
- High-power large-optical-cavity
- InGaAs strained reliable material
- laser structure laser technology contains three epitaxially stacked emitters for the highest power
- density and easy driver design
- The use of glue to attach the die is suggested.
Uses of pulsed laser diodes (PLDs)
Pulse-based laser diodes are extensively used in Lidar systems.
LiDAR in automobiles
LiDAR systems are a vital aspect of driver aid systems in autonomous or semi-autonomous vehicles, such as lane assist and emergency braking. The distance between the vehicle and nearby objects is calculated using the propagation time of very brief light pulses. A laser pulse is reflected and caught by a detector when it strikes a person or an item. The distance to the object can be calculated using the time between the emission of the laser beam and its detection. The vehicle’s safety system can then decide whether to brake or drive around the person or object, for example.
LiDAR in Industry
In industry, LiDAR systems are used for industrial automation, traffic control, range finders, and much more. Various measurement techniques, such as structured light, direct and indirect time of flight, are used in these systems. Semiconductor manufacturers have a wide range of pulsed laser diodes available in several package configurations, allowing for application flexibility and serving a wide range of power classes.
Conclusion
Pulsed Laser diodes are compact high functioning lasers used in laser chips, SMT laser, Radial laser, and so on.
