Single-mode Microchip Research Articles

Passively Q-Switched Single-Mode Microchip Laser Amplifying System Pumped with a Fiber Coupling QCW-LD Stack

Passively Q-Switched Single-Mode Microchip Laser Amplifying System Pumped with a Fiber Coupling QCW-LD Stack

Intensity modulation in single-mode microchip Nd:YAG lasers with asymmetric external cavity

Intensity modulation induced by the asymmetric external cavity in single-mode microchip Nd:YAG lasers is presented. Two kinds of experimental results are discussed based on multiple feedback effects. In one case, the intensity modulation curve is a normal sine wave, whose fringe frequency is four times higher than that of a conventional optical feedback system, caused by multiple feedback effects. In the other case, the intensity modulation curve is the overlapping of the above quadruple-frequency signal and conventional optical feedback signal, which is determined by the additional phase difference induced by the asymmetric external cavity. The theoretical analyses are in good agreement with the experimental results. The quadruple-frequency modulation of the laser output intensity can greatly increase the resolution of displacement measurement of an optical feedback system.

Intensity Tuning in Single Mode Microchip Nd:YAG Laser withExternal Cavity

We investigate the characteristics of intensity tuning in a single modemicrochip Nd:YAG laser with an external cavity. The undulation of laserintensity in a period of λ/2 change of the internal cavity length isobserved. Two different optical feedback cases are performed. One is anexternal cavity reflector perfectly aligned and the other is anexternal cavity reflector tilted. However, the fluctuation frequency oflaser intensity in a period of λ/2 change of the internal cavity lengthin these two cases is found to be determined by the ratio of externalcavity length to internal cavity length. Meanwhile, for the tiltedexternal cavity, the fluctuation frequency is also related to multiplefeedbacks in the tilted external cavity.

Mode hopping in single-mode microchip Nd:YAG lasers induced by optical feedback

The mode hopping phenomenon induced by optical feedback in single-mode microchip Nd:YAG lasers is presented. With optical feedback, mode hopping strongly depends on two factors: the ratio of external cavity length to intra-cavity length, and initial gains of the two hopping modes. When external cavity length equals an integral multiple of intra-cavity length, there is almost no mode hopping. However, if the external cavity length does not equal an integral multiple of intra-cavity length, mode hopping occurs. The ratio of external cavity length to intra-cavity length determines the position of two-mode hopping. The initial gains of the two hopping modes determine the corresponding peak values and oscillating periods of them in the intensity modulation curves.

Non-stationary characteristics of instability in a single-mode Nd:YVO 4 laser with fiber feedback

Random chaotic burst generation was experimentally observed in a single-mode microchip Nd:YVO4 laser with ber feedback. As the feedback strength was increased, a transition from stable relax- ation oscillation state to unstable random chaotic burst state appeared. Furthermore, the non-stationary characteristic of probability association was experimentally identied at the transition of the two states while similar characteristics were reported only by numerical simulations of simple dynamical systems. This implies the general feature of non-stationary property of the dynamic switching between two states at transition. The observed chaotic burst generation and non-stationary nature were reproduced numerically based on the Lang-Kobayashi model. PACS. 42.55.Rz Doped-insulator lasers and other solid state lasers

Phase-noise-driven instability in a single-mode microchip Nd:YVO/sub 4/ laser with feedback

We report the instability behaviors of a single-mode microchip solid-state laser subjected to external feedback. Two kinds of instabilities, random chaotic burst generations and random sinusoidal burst generations, were observed experimentally in an LD-pumped microchip Nd:YVO/sub 4/ single-mode solid-state laser with fiber feedback. These results are totally different form those observed in laser diodes with delay feedback systems, which have been widely studied in the last decades. The main features were reproduced numerically by utilizing the Lang-Kobayashi equations with phase noise, indicating phase-noise-driven dynamic instabilities.