Ding Yuan Tang

MEMS widely tunable lasers for WDM system applications

Tunable lasers have wide applications in DWDM systems to save inventory cost and to improve the optical network functionalities. The Microelectromechanical Systems (MEMS) technology has shown strong promise to miniaturize the conventional mechanical tunable lasers with adding merits of high compactness, high speed, batch production and so on. In this paper, external cavity tunable diode lasers using MEMS movable mirrors and rotary gratings as the external reflectors are presented. One tunable laser of 2 um x 1.5 um is formed by integration of a surface-micromachined 3D mirror with a diode laser and an optical fiber. A wavelength tuning range of 16 nm is obtained. In addition, deep-etched structures such rotary gratings, circular mirror, microlens, and grooves for diode laser and fiber are illustrated to form widely tunable lasers.

MEMS variable optical attenuator (VOA) for DWDM applications

Variable optical attenuators (VOAs) have wide applications in DWDM optical communication systems, for example, equalizing the power levers of different wavelength channels, flattening the gain of optical amplifiers, etc. A MEMS variable optical attenuator with fibers connectorized has been developed using proprietary drawbridge structure, which has achieved 1.5 dB insertion loss, 45 dB dynamic range and 37 ms response time, and requires only 8 V driving voltage. Finite element model and analytical model have also been studied and compared with the experimental data, showing that the two models predict the mechanical characteristics of MEMS VOA with reasonable accuracy.

Mechanism of bound soliton pulse formation in a passively mode locked fiber ring laser

Bound solitons with a soliton pulse width of 326 fs and a pulse separation of 938 fs are obtained in a passively mode locked fiber laser. Its creation and annihilation mechanism is experimentally investigated. Due to the existence of a strong cw laser in the cavity, the generation of bound solitons is found to be different from that of the nonbound normal solitons. We find that the number of stable bound soliton pairs in the cavity can be controlled only under lower pump power.

Novel cavity length feedback and stable operation of actively mode locked fiber ring laser

An actively harmonic mode locked fiber ring laser was setup and the stability in the vicinity of the harmonic modulation frequency was analyzed. A new cavity length feedback system was implemented to realize long-term stability. A chaos phenomena in the actively harmonic mode locked fiber ring laser was observed.

Observation of noise-like solitons

Noise-like ultra-short soliton pulses train of 72fs without CW components are observed from Figure-8 passively mode locked fiber laser; noise-like bound states of asymmetrical solitons train with pulse width of 103fs and separation of 585.5fs are also observed. The bound soliton separation and pulsewidth keep unchanged even after 1.2Km Single Mode Fiber transmission.

Tunable external-cavity laser using MEMS technology

This paper reports a tunable external-cavity diode laser using a MEMS curved mirror fabricated on a silicon-on-insulator (SOI) wafer. In addition to the many advantages coming with the MEMS technology, this laser has the benefits of low alignment requirement, easy integration/packaging and potentially large wavelength tuning range. It has a size of 1.5 mm/spl times/1 mm (not including the optical fiber), and obtains a wavelength tuning range of 10.6 nm. The output power is about 5 mW at 40 mA injection current (I/sub th/ = 26 mA).

Widely tunable lasers using MEMS gratings and mirrors

Tunable lasers have wide applications in DWDM systems to save inventory cost and to improve the optical network functionalities. The Microelectromechanical Systems (MEMS) technology has shown strong promise to miniaturize the conventional mechanical tunable lasers with adding merits of high compactness, high speed, batch production and so on. In this paper, external cavity tunable diode lasers using MEMS movable mirrors and rotary gratings as the external reflectors are presented. One tunable laser of 2 mm × 1.5 mm is formed by integration of a surface-micromachined 3D mirror with a diode laser and an optical fiber. In addition, deep-etched structures such rotary gratings, circular mirror, microlens, and grooves for diode laser and fiber are illustrated to form widely tunable lasers.

Closely spaced bound solitons with FWHM duration of 326 fs and separation of 938 fs from a passively mode locked fiber ring laser

Stable bound soliton pulses with FWHM duration 326 fs and fixed separation 938 fs were first observed in a passively mode locked fiber laser. The bound solitons formation mechanism and the transmission effects in fiber were investigated.

Compound pulse solitons in a passively mode-locked fiber laser

We demonstrate experimentally a novel form of double-pulse solitary waves in a passively mode-locked fiber ring laser. The new solitons are characterized as that they consist of two single solitons with fixed, discrete pulse separations. Through studying the interaction between bound-soliton pairs observed in a passively mode-locked fiber laser, we firstly revealed that the bound soliton pair behaves as a unit, and has exactly the same interaction properties as those of the single pulse soliton in the laser. Numerical simulations confirm the existence of the new form of solitons in the laser.

Operation stability of an actively mode-locked fiber ring laser

An actively harmonic mode locked fiber ring laser was setup, stability under the nearby of harmonic modulation frequency was analyzed. A new cavity length feedback system was implemented to realize the long-term stability. A chaos phenomena in the actively harmonic mode locked fiber ring laser was observed.