The Seal-355 series is UV DPSS laser system manufactured by JPT of Shenzhen. These are self-contained lasers with an integrated driver and digital control. They are intended for industrial uses such as marking and etching. The wavelength of the system is 355nm and the maximum output power varies from 3-5 watts depending on the model. The lasers are fully sealed from the elements and water cooled. It appears that all lasers of this series from JPT feature a TEM00 spatial mode beam.
Removing the top cover reveals an inner resonant cavity and the q-switch driver. On the reverse side is the driver board.
The resonant cavity cover has a tiny fan and associated wiring mounted to it, just to move some air around the sealed cavity.
The q-switch is manufactured by Coherent and the data sheet for this system mentions a frequency range of 20-200 kHz.
Wiring for the TECs, diode, and coax for the q-switch all enter through sealed ports on the rear of the resonant cavity. JPT used an interesting removable wiring harness and plate for the TEC and diode wiring to avoid an expensive sealed passthrough connector.
On the rear are just a few connections and indicators. The yellow LED indicates laser power/status. The red LED will illuminate to indicate a fault or temperature issue. The top D-SUB connector is for the 12V DC input, the bottom connector is for modulation, interlocks, and RS-232 control. The two plumbing fittings are for water cooling.
This interface board was included with this unit. It breaks out the signals from the D-SUB control connector to a terminal block and DB-9 for RS-232 control. The silkscreen descriptions along with the manual are a bit ambiguous. We have tested this laser, but presume it may be inoperable as we never got it to even enable the diodes, despite trying various combinations of modulation and interlocks. It also completely refused to communicate over the RS-232 serial interface. This unit is still a work in progress, we'll update this page if we get any further.
Removing the bottom cover reveals the combined laser diode driver, TEC driver, and digital control board. This board features an STM32 microprocessor, serial interface, temperature sensor inputs, and various outputs for the TECs and diodes. Many connections are labeled and there are some potentiometers. We have not yet evaluated their functions. Also visible is the fiber-coupled, 30W, 808nm pump diode. The output fiber is coiled up above the circuit board and enters the resonant cavity through an opening in the frame. The temperature of the pump diode is regulated by a TEC, for which the heat is dumped by water cooling.
