LiDAR & Laser Rangefinding
A pulsed time-of-flight system measures distance by timing the interval between an emitted laser pulse and its return. Everything good about that measurement starts at the emitter. The optical pulse the diode sends out is only as clean as the current pulse driving it, so the driver is not a support component in a rangefinder or LiDAR sensor, it is the part that sets the floor on how well the system can range. The same is true for atmospheric optical communication, where pulse shape and timing carry the signal.
Berkeley Nucleonics, through its Directed Energy Division, builds high-current drivers aimed squarely at this work. They produce fast, well-defined current pulses into pulsed laser diodes, and they are designed for OEM integration so a sensor builder can embed the driver inside a finished instrument rather than bolting a benchtop box onto a product.
The challenge
Range resolution in a pulsed system is tied directly to the emitted pulse. A shorter, sharper optical pulse lets the receiver resolve closer targets and separate returns that arrive nearly together, while a slow or smeared pulse blurs the timing and coarsens the measurement. That puts the burden on the driver to deliver a fast rise and a tightly controlled width into a diode that may demand tens or more than a hundred amps during the pulse. High current and a fast edge fight each other in any real circuit, because current wants inductance and a fast edge cannot tolerate it.
There is a second tension. Different ranging tasks want different pulses. A short-range, high-resolution scan favors the fastest, narrowest pulse the diode can survive, while a long-range shot may favor more energy in a slightly wider pulse. A driver fixed to one rise time forces a sensor designer to compromise, so the ability to tune the edge becomes a system-level capability rather than a detail. And because most of these drivers live inside a product, they have to fit, run from the available supplies, and accept a trigger from the host without dragging the timing budget with them.
It helps to be concrete about the link between pulse width and range. The receiver separates two returns only when the gap between them is wider than the emitted pulse, so the pulse width sets a practical floor on how close two targets can be and still be told apart. Rise time matters for the same reason at the leading edge: a slow edge delays and softens the moment the timer keys on, which adds uncertainty to every single-target measurement. A driver that controls both the width and the edge therefore controls the two quantities that most directly bound a pulsed system resolution, which is why edge control is treated as a first-order specification rather than a convenience.
The BNC approach
DEI rangefinder and LiDAR drivers are built as fast current sources with the edge under the designer's control. Variable rise-time control is a defining feature of the OEM modules: rather than living with a single fixed edge, the integrator sets the rise to match the ranging task, trading edge speed against pulse energy where the application calls for it. That single knob lets one driver serve a short-range, high-resolution mode and a longer-range mode in the same product.
The modules are designed to drop into a sensor. They present a defined trigger interface, run from practical supply rails, and are packaged for embedding rather than for a bench. The output stage and the recommended cabling are treated together, because a fast edge into a low-impedance diode survives only if the path between driver and emitter stays low in inductance. Keep that connection short and tightly paired and the diode sees the edge the driver produced; let it grow and the edge softens and the range resolution suffers with it.
For the fast, embedded case, the PCO-7121 is the OEM module built for rangefinder, LiDAR, and atmospheric-communication service, producing fast high-current pulses into pulsed laser diodes. Where a design needs more current with adjustable edges, the PCO-6141 delivers up to 60 A with variable rise-time control and the PCO-6131 delivers up to 125 A, also with variable rise-time control, both as OEM modules. Treat the current, rise-time, and rate figures as model capabilities and confirm them against the current published datasheet for your exact build.
Recommended instruments
Choose by current and by how much edge control the sensor needs. A compact rangefinder may run happily on the dedicated fast module, while a higher-current LiDAR emitter benefits from the adjustable-edge modules.
- PCO-7121: OEM module purpose-built for fast, high-current pulses into pulsed laser diodes in rangefinders, LiDAR, and atmospheric optical links.
- PCO-6141: 60 A OEM module with variable rise-time control, for tuning the emitted pulse to the ranging task.
- PCO-6131: 125 A OEM module with variable rise-time control, for higher-current emitters and longer-range work.
Getting started
Begin with the ranging requirement and work back to the pulse. Decide the minimum range resolution you need and the maximum range you have to reach, then translate that into a target pulse width and rise time at the emitter. Pick the diode and its peak current, choose the module whose current and rise-time range cover the task, and plan the trigger interface and the low-inductance connection to the diode early, because both shape the timing the finished sensor delivers. Talk to a BNC applications engineer at info@berkeleynucleonics.com or 800-234-7858 to match a driver to your sensor and integration.