This thesis presents new techniques for the development of compact and reliable laser sources using advanced fibre laser technology, aiming to enhance the multiphoton microscopy (MPM) for biomedical imaging applications. Our work explores second-order multiphoton-based imaging systems, including second harmonic generation (SHG), two-photon exited fluorescence (TPEF), and coherent antiStokes Raman scattering (CARS) microscopy. These systems require picosecond (ps) pulsed lasers with specific spectral and tunability characteristics. I demonstrate a compact, continuous wave (CW) seeded, synchronization-free optical parametric amplifier (OPA), bypassing the complex cavity design of optical parametric oscillators (OPOs). The OPA with 175 mW power level, 8 cm−1 spectral resolution, and 2 ps pulse duration is optimized for CARS microscopy, with rapid and precise tuning achieved through the periodically-poled lithium niobate (PPLN) OPA crystal. We also delve into third-order multiphoton imaging and three-photon microscopy (3PM) systems, which offer improved resolution and penetration depth. These systems require ultrafast lase.