150 MHz, All-Polarization-Maintaining Fiber Integrated Figure-9 Femtosecond Laser

We accomplish a compact 150-MHz figure-9 Er:fiber laser through the use of a hybrid device of wavelength division multiplexer and phase shifter. By combining the time-independent rate equation and nonlinear Schrödinger equation, evolution of the intracavity field towards stable mode locking state is presented. We further quantify the output characteristics of the 150-MHz figure-9 laser. Explicitly, 5.8-mW average power, center wavelength of 1561.2 nm and 3-dB spectral bandwidth of 29.2 nm are obtained. More importantly, an integrated root-mean-square relative intensity noise of 0.0016% [1 Hz, 1 MHz] and 75.8 fs timing jitter [100 Hz, 1 MHz] are measured at the fundamental repetition rate. Moreover, by referencing to a stable radio frequency, the fundamental repetition rate is locked with an in-loop relative instability of $2.78\times 10^{-12}$ at 1-s gate time.