Improvement of bandwidth in a 100 kHz swept laser source with phase controllable signal driving

Swept source optical coherence tomography(SS-OCT)is a new noninvasive technique for assessing tissue.Although it hasadvantages,such as being label-free,noninvasive,and with high resolution,it also has drawbacks:there has been no indepth research into identifying the driving of swept source.Based on preliminary research,we demonstrate a novel drivingmodulation method of a fiber Fabry–Perot tunable filter ranging phase adjustable as a tool for making bandwidth compensation of a swept laser source.This novel method is analyzed in detail;a swept laser source with a sweep rate of100.5 kHz over a range of 152.25 nm and at a center wavelength of 1335.45 nm is demonstrated.

Stable noise-like pulse generation in all-PM mode-locked Tm-doped fiber laser based on NOLM

A stable noise-like(NL)mode-locked Tm-doped fiber laser(TDFL)relying on a nonlinear optical loop mirror(NOLM)was experimentally presented.Different from the previous NL mode-locked TDFL with NOLM,the entire polarization-maintaining(PM)fiber construction was utilized in our laser cavity,which makes the oscillator have a better resistance to environmental perturbations.The robust TDFL can deliver stable bound-state NL pulses with a pulse envelope tunable from〜14.1 ns to〜23.6 ns and maximum pulse energy of〜40.3 nj at a repetition rate of〜980.6 kHz.Meanwhile,the all-PM fiber laser shows good power stability[less than〜0.7%)and repeatability.

0.33 mJ, 104.3 W dissipative soliton resonance based on a figure-of-9 double-clad Tm-doped oscillator and an all-fiber MOPA system

We demonstrate, for the first time, to the best of our knowledge, an all-fiber figure-of-9 double-clad Tm-doped fiber laser operating in the dissipative soliton resonance(DSR) regime. Stable mode-locked rectangular pulses are obtained by using the nonlinear amplifying loop mirror(NALM) technique. A long spool of high-nonlinearity fiber(HNLF) and a segment of SMF-28 fiber are used to enhance the nonlinearity of the NALM loop and to obtain a large all-anomalous regime. Output power and pulse energy are further boosted by using a three-stage master oscillator power amplifier(MOPA) system. At the maximum pump power, average output power of up to 104.3 W with record pulse energy of 0.33 mJ is achieved with a 2 μm DSR-based MOPA system.

Facile active control of a pulsed erbium-doped fiber laser using modulation depth tunable carbon nanotubes

Short pulsed fiber lasers have been widely made using single-walled carbon nanotubes as a saturable absorber(SA). However, most of the currently used devices can only operate in one determined operation state with an unchangeable modulation SA depth in the cavity, which significantly limits their application in photonic devices.In this paper, well-aligned carbon nanotube arrays are synthesized using zeolite AlPO_4-5 as a template, which features anisotropic optical absorption. The linear optical absorption of the as-synthesized carbon nanotube arrays can easily be tuned by adjusting a polarization controller, thus providing a tunable modulation depth for the carbon nanotube SA. By exploiting this SA in an erbium-doped fiber laser cavity, both Q-switched and modelocked pulsed lasers are achieved by simply adjusting a polarization controller under a fixed pump power of 330 mW. In addition, the repetition rate of the Q-switching and pulse duration of the mode-locking can be tuned according to the variation of modulation depth. Moreover, soliton molecules can be obtained when the modulation depth of the SA is 4.5%.

Two-micron all-fiberized passively mode-locked fiber lasers with high-energy nanosecond pulse

We report on mode-locked thulium-doped fiber lasers with high-energy nanosecond pulses,relying on the transmission in a semiconductor saturable absorber(SESA)and a carbon nanotube(CNTs-PVA)film separately.A section of an SMF-MMF-SMF structure multimode interferometer with a transmission peak wavelength of^2003 nm was used as a wavelength selector to fix the laser wavelength.When the SESA acted as a saturable absorber(SA),the mode-locked fiber laser had a maximum output power of^461 mW with a pulse energy of^0.14µJ and a pulse duration of^9.14 ns.In a CNT-film-based mode-locked fiber laser,stable mode-locked pulses with the maximum output power of^46 mW,pulse energy of^26.8 nJ and pulse duration of^9.3 ns were obtained.To the best of our knowledge,our experiments demonstrated the first 2µm region‘real’SA-based dissipative soliton resonance with the highest mode-locked pulse energy from a‘real’SA-based all-fiberized resonator.