In-phased second harmonic wave array generation with intra-Talbot-cavity frequency-doubling.

The Talbot cavity is one promising method to synchronize the phase of a laser array. However, it does not achieve the lowest array mode with the same phase but the highest array mode with the anti-phase between every two adjacent lasers, which is called out-phase locking. Consequently, their far-field images exhibit 2-peak profiles. We propose intra-Talbot-cavity frequency-doubling. By placing a nonlinear crystal in a Talbot cavity, the Talbot cavity generates an out-phased fundamental wave array, which is converted into an in-phase-locked second harmonic wave array at the nonlinear crystal. We demonstrate numerical calculations and experiments on intra-Talbot-cavity frequency-doubling and obtain an in-phase-locked second harmonic wave array for a Nd:YVO4 array laser.

A 113 fs fiber laser operating at 1.56 mum using a cascadable film-type saturable absorber with P3HT-incorporated single-wall carbon nanotubes coated on polyamide.

We successfully fabricated a cascadable film-type single-wall carbon nanotube (SWNT) saturable absorber coated on aromatic polyamide film, in which the saturable absorption effect can be controlled with the number of films. A conductive polymer P3HT (poly-3-hexylthiophene) was adopted to obtain a uniform SWNT solution. We applied saturable absorber films to a passively mode-locked fiber laser and successfully generated a 113 fs, 42 MHz pulse by inserting two film layers between fiber connectors in the cavity.

131 fs, 33 MHz all-fiber soliton laser at 1.07 microm with a film-type SWNT saturable absorber coated on polyimide.

We present a 1.07 microm all-fiber femtosecond soliton laser employing a film-type saturable absorber with a P3HT (poly-3-hexylthiophene) incorporated SWNT coated on polyimide film. We optimized the laser cavity as a dispersion-managed soliton laser with photonic crystal fiber (PCF) as an anomalous dispersion fiber at 1.07 microm. As a result, a 131 fs, 33 MHz pulse was successfully generated with a simple laser configuration.

An 88 fs fiber soliton laser using a quantum well saturable absorber with an ultrafast intersubband transition.

We demonstrate a 1.5 microm passively mode-locked fiber laser using an intersubband transition (ISBT) in a quantum well as a saturable absorber. The saturable absorption characteristic of faster than 1 ps in the ISBT was utilized for femtosecond pulse generation. We designed the laser cavity as a soliton laser, which enabled us to generate a stable pulse. As a result, an 88 fs, 42 MHz soliton pulse was successfully generated.

A passively mode-locked femtosecond soliton fiber laser at 1.5 microm with a CNT-doped polycarbonate saturable absorber.

We report a new 1.5 mum femtosecond fiber soliton laser incorporating a polymer saturable absorber that consists of polycarbonate (PC) with carbon nanotubes (CNTs). We installed the polymer in a fiber laser with a cavity length of 5.1 m, in which an erbium-doped fiber was used as the gain medium. Stable passive mode-locking was achieved for a pump power of 303 mW at 39 MHz, and a pulse width of 115 fs with an average output power of 3.4 mW was obtained.

147 fs, 51 MHz soliton fiber laser at 1.56 microm with a fiber-connector-type SWNT/P3HT saturable absorber.

We fabricated a fiber-connector-type saturable absorber in which SWNTs and P3HT (poly-3-hexylthiophene) were coated on the fiber connector end. This saturable absorber allowed us to realize a short laser cavity length. We used a soliton cavity configuration to generate the shortest pulse (147 fs) at the highest repetition rate (51 MHz) yet obtained with carbon nanotubes (CNT) related saturable absorbers.