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Picosecond Pulsed Drivers

PDL 828 "Sepia II"

Computer Controlled Multichannel Picosecond Diode Laser Driver

  • Modular system, drives up to 8 lasers or LED heads
  • Adjustable repetition rates from single shot to 80 MHz or CW operation
  • Computer controlled through USB
  • Various operation modes: bursts, simultaneous, delayed, sequential, burst sequence
  • Pulse energy control of attached laser or LED heads
  • Synchronization output, two gating options (fast/slow gate)
  • Suited for LDH Series, LDH-FA Series and PLS Series

5 year limited warrantyThe PDL 828 "Sepia II" is a high-end, multichannel driver for the picosecond pulsed laser diode heads of the LDH Series and LDH-FA Series as well as for the sub-nanosecond pulsed LEDs of the PLS Series. Wavelength changes are simply performed by plugging in a different laser or LED head. The high quality and reliability of the PDL 828 is expressed by a unique 5-year limited warranty.

Ultra flexible driver solution

Screenshot of the operation software of the PDL 828 The PDL 828  “Sepia II” provides maximum flexibility for multiple wavelengths applications. It drives any combination of up to eight laser or LED heads in parallel or in a user defined sequence. The whole system has no manual controls – instead it is easily configured and controlled through a dedicated Windows control software via a USB connection. Last settings are saved inside the PDL 828 to allow stand-alone operation, making it a powerful device for measurement automation. A computer library to access the functions of the PDL 828 for custom development is also provided with the device.

Individual modular assembly

The PDL 828 is available in different sizes to control any number of laser / LED heads between 2 and 8 at the same time.  Each PDL 828 is assembled individually from a mainframe with power supply and computer interface and two modules: an oscillator and burst generator module and up to eight laser driver modules. The communication between the modules is achieved via external cabling – delays can thus be easily inserted by using different cable lengths. The PDL 828 allows to produce a wide range of user-definable pulse patters such as sequences or bursts. All connected laser/LED heads can also be fired at the same time.

Powerful oscillator module

PDL 828  in a small configurationTwo models of oscillator and burst generator modules are available, each with eight individually addressable trigger outputs (output channels). Both modules feature a rotary sequencer with programmable channels where one channel must be completed before the next one activates.
The SOM 828 module allows grouping of adjacent output channels so that they can be activated at the same time. The 8 channels of the SOM 828-D module can be freely combined with each other to yield complex pulse patterns where one channel will activate simultaneously with its combination partners. Alternatively, instead of combining channels, an individual, software controlled delay can be introduced for any non-combined channel.
Both modules offer burst operation, where multiple pulses can be output from either single, grouped, or combined channels before the next channel becomes active. Both oscillator modules have their own (variable) synchronization output, external trigger input as well as auxiliary input and output connectors.

Flexible laser driver module

A laser driver module is necessary for each laser/LED head that needs to be connected and controlled at the same time by the PDL 828. The timing of the emitted pulses can be controlled by an external trigger signal, which is typically provided by the oscillator module or any other source providing a NIM compatible signal. As a special feature, each Laser Driver Module can also operate independently from the other modules driven by its internal low-jitter oscillator at six fixed, user-selectable frequencies (80, 40, 20, 10, 5 or 2.5 MHz). All emitted laser pulses are accompanied by a synchronization output at the front panel of the laser driver module. This signal is always synchronised to the trigger source, independent from the selection of triggering mode (i.e., external or internal triggering).

Complete control of laser power and CW operation

The intensity of the laser emission is controlled via an internal voltage in steps of 0.1% of its full scale value. However, due to the non-linear behaviour of laser diodes, the voltage setting does not linearly correspond to the output power, i.e., a voltage of 50% does not correspond to 50% of the maximum output power. A special feature of the PDL 828 is to switch between CW and pulsed mode with the LDH-D Series of laser heads.

Gating options

For special applications using, e.g., scanning devices, the PDL 828 provides two special gating options that allow to suppress the laser emission by an external signal: A slow gate, that reduces setting times of the laser heads to a minimum at slow on / off periods (seconds) and a fast gate, that can perform transitions within nanoseconds, i.e., in between two pulses. The fast gate also provides high pulse stability when the on/off signal is periodic and fast (milliseconds).

For applications that require only a single wavelength, the alternative single channel driver PDL 800-D can be provided.

Large, L: 1 slot for oscillator module, 8 slots for laser driver modules
Small, S: 1 slot for oscillator module, 2 slots for laser driver modules
Power supply 220/240 or 110/120 VAC, 50/60 Hz, max. 150 Watts (large) or 70 Watts (small)
Dimensions large: 464 × 310 × 140 mm (w × d × h)
  small: 250 × 310 × 140 mm (w × d × h)
Oscillator module
Outputs 8 trigger (NIM), 1 synchronization (NIM), 1 auxiliary
Inputs 1 external trigger, 1 auxiliary (TTL)
Operation mode rotary, programmed sequence of one channel must be completed before next channel is activated, adjacent channels can be grouped; multiple channels can be either combined or delayed (SOM 828-D only)
Oscillator type crystal locked
Master oscillator frequencies 80, 64, 50 MHz (selectable)
Repetition frequency user-selectable, derived from the selected master frequency or an external trigger source by division through any integer factor between 1 and 256 (SOM 828) or 1 and 65536 (SOM 828-D)
Synchronization output
Timing synchronous to repetition frequency, timing position stepwise adjustable within the limits of the repetition frequency, stepsize equals master oscillator period
Masking synchronization pulses can be inhibited (masked), mask size selectable in integer steps between 0 and 255, stepsize equals repetition period
Amplitude < -800 mV into 50 Ohms (NIM)
Auxiliary output
Timing at start of complete trigger sequence
Amplitude +500 mV into 50 Ohms (SOM 828); +1.5 into 50 Ohms (SOM 828-D)
External trigger input
Amplitude -5 to +5 V (maximum limits)
Trigger level -1.2 to +1.2 V
Frequency range up to 40 MHz (SOM 828); up to 60 MHz (SOM 828-D)
External synchonization 6.25 to 100.00 MHz (SOM 828-D only)
Burst length up to 16.7 million pulses
Laser driver module
Inputs 1 trigger (NIM), 2 gating (TTL)
Outputs 1 synchronization (NIM)
Operation mode pulsed or continous-wave
Master oscillator frequency 80 MHz
Repetition frequency 80, 40, 20, 10, 5 or 2.5 MHz (user-selectable)
Operating system WindowsTM 7 / 8 / 8.1 / 10
PC interface USB 2.0

All Information given here is reliable to our best knowledge. However, no responsibility is assumed for possible inaccuracies or omissions. Specifications and external appearances are subject to change without notice.

Understanding the flexibility of the oscillator module

Both types of oscillator modules (SOM 828 and SOM 828-D) have a rotary sequencer with eight so-called burst channels that can each be addressed individually. These burst channels can be either activated individually one after another, grouped with adjacent channels, or freely combined (SOM 828-D only) for simultaneous activation. Burst operation can be enabled for single as well as grouped or combined burst channels, allowing outputting multiple pulses before the next channel becomes active. The SOM 828-D module allows introducing individual, software controlled delays in burst channels that are not combined. Additionally, both oscillators have their own synchronization output, external trigger input as well as auxiliary input and output connector.

The oscillator module has eight (individual) trigger outputs (channels) that can each be addressed individually. For example, channels can be combined to be activated at the same time or each channel can be individually activated in a sequence. To enable burst operation, multiple pulses can be output from one channel (or from combined channels) before the next channel becomes active. Additionally, the oscillator has its own synchronization output, an external trigger input as well as an auxiliary input and output connector.

Rotary working principle

PDL 828 - rotary working principleGenerally speaking, the oscillator module works in a rotary fashion, meaning that the programmed sequence of burst channels 1 (C1) through 8 (C8) must be completed before the first one becomes active again. All channels can therefore be activated individually in a rotary sequence. Adjacent channels can also be combined for simultaneous operation. The SOM 828-D oscillator module even allows combining burst channels in any arbitrary fashion, so that the selected channel will output the same number of pulses at the same time as its combination partners do. The auxiliary input can be used to inhibit the oscillator from starting the output period, i.e., to "start" from channel 1. If the signal is provided during the rotation through the channels, one full sequencer period will be finished nonetheless. The auxiliary output is used to signal the start of a period. It is active when a period is finished (i.e., if channel 8 has been active) and a new one is about to start.

Repetition rates between 0.76 kHz or 196 kHz and 80 MHz

PDL 828 - repetition rates derived from base oscillator by divisionThe oscillator modules of the PDL 828 provide a wide range of user selectable repetition rates to be used as the main clock rate. All repetition rates are in principle derived from an internal crystal oscillator along with an integer frequency divider. Both oscillator modules feature three internal user-selectable crystal oscillators with base frequencies (F) of 80, 64 and 50 MHz. Each base frequency can be further reduced by an integer division (D) ranging from 1 to 255 (SOM 828) or 1 to 65536 (SOM 828-D). The highest repetition rate for both modules is therefore 80 MHz and the lowest repetition rates are 50 MHz/255~196 kHz and 50 MHz/65536~0.76 kHz. It is also possible to provide an external trigger signal instead of using one of the internal oscillators. The frequency divider is also active on external trigger signals, thereby allowing virtually any repetition rate between single shot and 80 MHz.Repetition rates between 196 kHz and 80 MHz

Defining bursts and combining channels

PDL 828 - burst patternsBoth oscillator modules allow outputting any number of pulses between 1 and 16.772.215 (16.7 million) from one burst channel (C) before the next one becomes active (bursts - B). Adjacent burst channels can also be grouped to emit the same number of pulses at the same time, if the burst lengths of the channels following the first one to be grouped are set to 0. The SOM 828-D oscillator module furthermore allows free combining of burst channels. The target channel will output the same number of pulses at the same time as its combination partners.

The pulse output from each channel can be enabled or disabled. However, if a burst channel is disabled, it is not "eliminated" from the rotary sequence. Instead, the programmed number of pulses is still processed, but simply no signal is present at the corresponding output port. This is useful to insert time gaps between two bursts.

Variable synchronization signal

PDL 828 - synch signalEach pulse that is output at any of the eight channels can be accompanied by a synchronization signal (S) at the sync out connector. This synchronization signal can be used to control external hardware like, e.g., providing the start pulse for a TCSPC system. It can be enabled and disabled individually for each channel. One special feature of the PDL 828 is that the synchronization signal can be time shifted at lower repetition frequencies. If the divider ratio is >1, the sync pulse can be moved within the main clock period (the divided signal) in steps of the crystal oscillator's period (pre-sync - P). If the pre-sync is set to a value equal or higher than the divider, the synchronization signal will be disabled.

PDL 828 - synch pulsed can be maskedAn additional option to influence the synchronization signal is to mask (M) a defined number of pulses. Masking in this context means that no synchronization signals are output. The number of omitted pulses can be set to any integer value between 0 and 255. The sync mask can also be inverted (iM), i.e., not the number of omitted pulses is specified, but the number of actual output pulses. Again, the number of inverted masked synchronization pulses can be set to any integer value between 0 and 255. A value of 0 leads to no synchronization output at all.

Latest 10 publications referencing Pulsed Diode Lasers (PDL Series, LDH-Series, LDH-FA Series)

The following list is an extract of 10 recent publications from our bibliography that either bear reference or are releated to this product in some way. Do you miss your publication? If yes, we will be happy to include it in our bibliography. Please send an e-mail to info@picoquant.com containing the appropriate citation. Thank you very much in advance for your kind co-operation.