The High Photon Efficiency (HPE) standard is a promising approach for, low Size, Weight and Power (SWaP) optical terminal for space communications. In this paper, we report the creation of a breadboard demonstrator CCSDS compliant HPE source, capable of a Pulse Position Modulation (PPM) order of 256 with an average power of 4W and kW level peak power. The HPE source operates in the optical C-band utilising high bandwidth external intensity modulation and high power optical fibre amplifier technology to enable a range of modulation/data-rates to be accessed. Additional external phase modulation is employed as an active Stimulated Brillouin Scattering (SBS) mitigation to achieve the high output peak power requirements. This laser breadboard utilises a 19” rack enclosure allowing easy integration with a HPE transmitter demonstrator breadboard at TNO to demonstrate the combined modem and laser performance. We present testing results such as electrical to optical efficiency and optical pulse characteristics of the system under a range of modes of Continuous Wave (CW) and pulsed operation. Employing the HPE pulsed laser source, we simulated an optical link and introduce results alongside the road-map toward space qualification.