A high power ultra-bright pump source HPUBPS, comprising: at least one seed source generating a low-noise signal light at a first wavelength; a sub-pump unit (14, 18) being seperate from the at least one seed source configured to receive and amplify the signal light generated from the at least one seed source and having: a plurality of sub-pump multimode laser diodes combined together to emit a sub-pump light at a second wavelength shorter than the first wavelength, and a Nd wavelength fiber converter which is a fiber amplifier configured with a Nd-doped fiber having a core supporting multiple modes and at least one cladding operative to convert the second wavelength of the sub-pump light to the first wavelength of the signal light, the Nd wavelength fiber converter being configured to emit the amplified signal light having: a noise level substantially identical to that one of the low-noise signal light, a brightness substantially equal to nB, wherein n is a number of the sub-pump laser diodes, and B is brightness of each sub-pump laser diode, and an output power substantially equal to nPd, wherein Pd is a power of each sub-pump laser diode, and n is the number thereof; and a single mode Yb fiber oscillator receiving the amplified signal light and having peak emission at a third wavelengths around 976 nm. at least one seed source generating a low-noise signal light at a first wavelength; a sub-pump unit (14, 18) being seperate from the at least one seed source configured to receive and amplify the signal light generated from the at least one seed source and having: a plurality of sub-pump multimode laser diodes combined together to emit a sub-pump light at a second wavelength shorter than the first wavelength, and a Nd wavelength fiber converter which is a fiber amplifier configured with a Nd-doped fiber having a core supporting multiple modes and at least one cladding operative to convert the second wavelength of the sub-pump light to the first wavelength of the signal light, the Nd wavelength fiber converter being configured to emit the amplified signal light having: a noise level substantially identical to that one of the low-noise signal light, a brightness substantially equal to nB, wherein n is a number of the sub-pump laser diodes, and B is brightness of each sub-pump laser diode, and an output power substantially equal to nPd, wherein Pd is a power of each sub-pump laser diode, and n is the number thereof; and a single mode Yb fiber oscillator receiving the amplified signal light and having peak emission at a third wavelengths around 976 nm. a plurality of sub-pump multimode laser diodes combined together to emit a sub-pump light at a second wavelength shorter than the first wavelength, and a Nd wavelength fiber converter which is a fiber amplifier configured with a Nd-doped fiber having a core supporting multiple modes and at least one cladding operative to convert the second wavelength of the sub-pump light to the first wavelength of the signal light, the Nd wavelength fiber converter being configured to emit the amplified signal light having: a noise level substantially identical to that one of the low-noise signal light, a brightness substantially equal to nB, wherein n is a number of the sub-pump laser diodes, and B is brightness of each sub-pump laser diode, and an output power substantially equal to nPd, wherein Pd is a power of each sub-pump laser diode, and n is the number thereof; and a noise level substantially identical to that one of the low-noise signal light, a brightness substantially equal to nB, wherein n is a number of the sub-pump laser diodes, and B is brightness of each sub-pump laser diode, and an output power substantially equal to nPd, wherein Pd is a power of each sub-pump laser diode, and n is the number thereof; and a single mode Yb fiber oscillator receiving the amplified signal light and having peak emission at a third wavelengths around 976 nm.