Compact laser diode array based on epitaxially integrated AlGaAs/GaAs heterostructures
Programmable Pulsed Diode Laser
Programmable pulse shape
200 ps bin width
512 time bins
8 bit resolution
The PPL 512 is a programmable diode laser that can generate arbitrary pulse shapes with a timing resolution of 200 ps. An amplitude level with 8 bit resolution can be assigned to each time bin having a width of 200 ps. A laser signal with the defined pulse shape is the output to a single mode fiber.
By programming fast current slopes, gain switched operation can be achieved, which results in picosecond optical output pulses. Also, undesired ringing effects at fast switch-on transients can be reduced by defining specific current ramps. Moreover, saturation effects of optical amplifiers can be pre-compensated, which makes the device an ideal seeding source for fiber or solid-state amplifiers.
The PPL 512 can be configured to provide pulses at wavelengths such as 1030 or 1064 nm, 1.5 or 2 µm, as well as many wavelengths in the visible range.
Pulse examples
The plots presented here show pulse shapes generated by the PPL 512 connected to a laser diode. The optical output of the diode was measured using a combination of photodiode and digital sampling oscilloscope.
The pulse shape on the left has a temporal width of ca. 45 ns and features two pairs (high, low) of sharp intensity peaks in the pattern high, low, low, high. The pulse shown in the middle plot features a house-like shape with a rising slope followed by a declining one. This pulse has a temporal width of ca. 30 ns. The rightmost plot contains a periodic sawtooth shape, where each “tooth” has a temporla width of ca. 100 ns.
The repetition rate at which all of these pulse shapes were generated was ca. 9.8 MHz, corresponding to 512 time bins, each having a bin width of 200 ps.
The PPL 512 can also generate bursts patterns as shown in the plots below. Here a pattern of a repeating pattern of 4 bursts consisting of 2 packets of 5 narrow pulses each was generated. Each individual pulse has a temporal width of ca. 90 ps and the shortest spacing between two packets of 5 pulses was 23 ns. Between each couple of pulse packets, a temporal spacing of 66 ns was introduced. As for the pulse shapes shown above, the burst pattern can be generated at a rate of about 9.8 MHz.
