Rapid infrared wavelength access with a picosecond PPLN OPO synchronously pumped by a mode-locked diode laser

Abstract

We theoretically and experimentally investigate wavelength tuning of synchronously pumped optical parametric oscillators (OPOs) on changing the cavity length or the pump-repetition rate. Conditions for rapid and wide-range wavelength access are derived. Using an OPO pumped directly by a mode-locked diode-laser master-oscillator poweramplifier (MOPA) system, an all-electronically controlled access to near-and mid-infrared wavelengths is demonstrated. The singly (signal) resonant OPO is based on periodically poled lithium niobate (PPLN) and emits 8 ps idler pulses at a repetition rate of 2.5 GHz in the wavelength range 1986 to 2348 nm (signal: 1530 to 1737 nm). Wavelength tuning over 114 nm (signal) and 189 nm (idler) is achieved solely by electronically varying the repetition rate of the diode-laser oscillator over 720 kHz. By controlling the repetition rate with a programmable driver, an arbitrary emission sequence of the OPO on two wavelength channels is generated, with access times as short as 10 µs. 11 OPO wavelengths equally spaced in the range 1627-1689 nm (signal) or 2054-2154 nm (idler) could be addressed.

1-GHz repetition rate femtosecond OPO with stabilized offset between signal and idler frequency combs

“…Here, ΔL is the offset between the geometrical cavity lengths of the OPO and the pump laser, L C is the length of the PPLN crystal and n g the group index of the signal pulse in the PPLN. This effect is widely used for wavelength tuning of synchronously pumped OPOs [23]. As a second condition, the signal comb teeth resonating in the OPO cavity must fulfill the standing wave condition.…”

“…More precise cavity length control is enabled by using a translation stage to adjust the OC2 position and a piezoelectric transducer (PZT) supporting M3. Here, cavity length tuning [23] of the signal center wavelength is continuously feasible from 1480 to 1580 nm. The signal output power for a center wavelength at 1558 nm is 80 mW and its spectral full width at half maximum (FWHM) is 40 nm.…”

Narrowband, tunable, infrared radiation by parametric amplification of a chirped backward-wave OPO signal

“…Additionally it would be very challenging to generate picosecond, narrowband and tunable pulses with energies in the µJ range with this technique. Synchronously-pumped OPOs with intra-cavity spectral filtering have been used to generate dual narrowband, tunable picosecond pulses [10,11], but with low output powers. Reaching µJ energies would require employing a separate synchronized laser to pump an additional optical parametric amplifier (OPA) and a pulse-picker to reduce the repetition rate appropriate for the pump laser.…”

Synchronously pumped optical parametric oscillator driven by a femtosecond mode-locked fiber laser

“…The explanation of this effect is based on the presence of group-velocity dispersion in the resonator, arising predominantly from the PPLN crystal. 10,14 In the absence of any element to select the signal wavelength deliberately, oscillation occurs at the wavelength that maximizes the net gain, this being determined by a compromise between the temporal constraint imposed by synchronism and the frequency constraint imposed by the parametric gain line. An increase in cavity length requires, for synchronism, a higher signal group velocity.…”