The paper reports on M Squared Lasers' recent work in the field of narrow-linewidth, continuous wave (CW) optical
parametric oscillators (OPO) that utilise the semiconductor disk laser (SDL) format for intra- and extracavity pumping
schemes. For the experimental investigation, InGaAs quantum well gain structures were employed to produce compact
SDLs which were subsequently used to pump OPOs based on periodically poled lithium niobate (PPLN).
Using the intracavity architecture, a compact, CW, narrow-linewidth OPO was developed, capable of delivering up to
250 mW of narrow-linewidth idler output power (at ~3.3 μm). The SDL maintained stable single longitudinal mode
operation and the spectral bandwidth of the OPO output was measured to be <0.14nm. A full discussion of the
experimental set-up and results will be presented, together with a review of the potential issues and limitations in
pursuing the development of intracavity pumped, single frequency OPOs.
In addition to the intracavity work, extracavity approaches will also be discussed and their performance compared to
those produced from the intracavity device. For the purpose of pumping singly resonant extracavity PPLN OPOs, high
power (>15W), single frequency SDLs were developed using single- and multichip configurations. The extracavity OPO
pumped by these sources delivered up to 950 mW of idler output power, with a minimum threshold of 2.4 W and tuning
range from 2.8 μm to 3.6 μm. Further details of the high power, single frequency SDLs as well as the extracavity OPO
will be discussed, with specific focus on the advantages and disadvantages of multi-chip and single-chip arrangements
for single frequency SDLs.