Ultracompact zigzag fiber-feedback multipass optical parametric oscillator

Area of Science:

• Nonlinear Optics
• Laser Physics
• Ultrafast Photonics

Background:

• Fiber-feedback optical parametric oscillators (OPOs) are crucial for tunable ultrashort pulse generation.
• Limited single-pass gain in OPOs often requires additional amplification stages, increasing system complexity and cost.

Purpose of the Study:

• To overcome the gain-bandwidth limitations of traditional OPOs.
• To develop a compact and efficient multipass amplification technique for OPOs.
• To eliminate the need for post-amplification in tunable ultrashort pulse sources.

Main Methods:

• Implementation of a novel zigzag geometry for multipass amplification within a single nonlinear crystal.
• Integration of the zigzag amplification into a fiber-feedback OPO cavity.
• Dispersion engineering across multiple passes to maintain pulse quality.

Main Results:

• Achieved shot-noise-limited 100 fs pulses with a zigzag fiber-feedback multipass OPO (FFMOPO).
• Demonstrated continuous tunability from 1360 nm to 1800 nm at a 76 MHz repetition rate.
• Obtained up to 1.2 W average power and 40% system conversion efficiency.

Conclusions:

• The ultracompact zigzag FFMOPO design breaks the gain-bandwidth limit, offering high gain and broad bandwidth.
• This technology eliminates the need for post-amplification, reducing size and cost.
• The FFMOPO is ideal for applications in ultrafast spectroscopy and bioimaging requiring compact tunable pulse sources.