Single-frequency 45-mJ pulses from a MOPA system using an Er,Yb:glass planar waveguide amplifier and a large mode area Er-doped fiber amplifier

Abstract

We demonstrate a master oscillator power amplifier (MOPA) system that emits single-frequency high-energy optical pulses at 1540 nm using an Er,Yb:glass planar waveguide amplifier and a large mode area Er-doped fiber amplifier. A double under-cladding and a 50-µm-thick core structure are employed for the planar waveguide amplifier to increase the output energy without degrading the beam quality. A pulse energy of 45.2 mJ with a peak power of 27 kW is generated at a pulse repetition rate of 150 Hz with a pulse duration of 1.7 µs. Moreover, the beam quality factor M2 of the output beam is 1.84 at the highest pulse energy thanks to its waveguide structure.

Single-frequency erbium-doped fiber amplifier with high energy gain at low repetition rates

“…1 Recently, 0.65 mJ output from a fiber amplifier was further boosted to 45 mJ by an Er:Yb doped planar waveguide power amplifier at a low repetition rate of 150 Hz. 2 Polarization-maintaining (PM) fiber-amplifiers based on a master-oscillator-power-amplifier (MOPA) configuration are attractive candidates for such systems, provided their design overcomes the challenge of achieving together high beam quality and high pulse energy, while also minimizing the impact of stimulated Brillouin scattering (SBS). Undesirable power build-up in between signal pulses increases with decrease in repetition rate in CW-pumped amplifiers.…”

Single-frequency high-energy pulses from an Er:Yb glass planar waveguide amplifier with good beam quality

“…6) In particular, pulses with a high energy (>1 mJ), a long pulse duration (>100 ns), a single frequency and good beam quality (M 2 < 2) are required in the research field of coherent Doppler wind lidars (CDWLs). [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] Several groups have developed master oscillator power amplifier (MOPA) systems using an Er, Yb: co-doped fiber amplifier [10][11][12][13][14][15][16] or an Erdoped fiber amplifier (EDFA) [17][18][19][20][21][22][23] with a large mode area (LMA) to avoid stimulated Brillouin scattering (SBS) and laser induced damage (LID). Most work on all-fiber MOPA systems has been demonstrated with pulse energies of up to 1.5 mJ due to SBS or amplified spontaneous emission (ASE) dynamics.…”

“…14,16) Planar waveguide amplifiers (PWAs) made of Er, Yb:glass enable us to obtain higher pulse energies. 24,25) Good heat dissipation due to plane-to-plane bonding between the PWA and a heat sink enables high density pumping and avoids thermal lensing. A planar waveguide structure can suppress the degradation of the beam quality associated with the expansion of the mode field area compared to a twodimensional waveguide.…”

“…CDWL measurements over 30 km have been demonstrated using a PWA which emits 3.2 mJ pulses with a M 2 of 1.3 at 4 kHz. 24) 45.2 mJ pulses at 150 Hz have also been demonstrated using an improved large PWA as the main amplifier and an LMA EDFA as the preamplifier 25) for spaceborne mission. [25][26][27] A symmetrical double under-cladding structure with a 50 μm core was employed to increase the volume of the PWA's active area and to mitigate the possibility of LID.…”

“…24) 45.2 mJ pulses at 150 Hz have also been demonstrated using an improved large PWA as the main amplifier and an LMA EDFA as the preamplifier 25) for spaceborne mission. [25][26][27] A symmetrical double under-cladding structure with a 50 μm core was employed to increase the volume of the PWA's active area and to mitigate the possibility of LID. An LMA EDFA 20,23) was introduced to increase the energy of the input pulses significantly over that of a single-mode EDFA.…”