Abstract: A hybrid type passively and actively mode-locked laser scheme is disclosed, in which not only the capability of producing ultra-short optical pulses by the conventional passively mode-locked optical fiber laser scheme is utilized, but also the repetition rate variation capability and the optical pulse synchronization capability of the conventional actively mode-locked laser scheme are utilized. Consequently, all the advantages of the two conventional laser schemes are obtained in the present invention. Specifically, two loops are coupled together, and one of the two loops consists of a non-linear amplifying loop of the existing passively mode-locked scheme, while the other loop includes an optical modulator and an optical gain medium for the loop to perform the function of an actively mode-locked scheme. Further the other loop includes a time delay line so as to adjust the laser oscillation repetition rate.

Abstract: The wavelength tunable mode-locking optical fiber laser comprises non-linear amplifying loop mirror part having a light pumping lase diode, a gain medium doped optical fiber having the gain medium for oscillating the rambling light wave sequentially, a dispersion shifted optical fiber, and first polarization controller for making the continuous oscillation light wave to be maximized by adjusting the polarization of said propagating light. All elements of the non-linear amplifying loop mirror part are combined to each other in loop type on the above clock direction.

Abstract: A measurement of nonlinear refractive index coefficient of an optical fiber with a Sagnac interferometer, comprises the steps of employing the optical fiber in a Sagnac interferometer, splitting a signal beam into two signals, launching the two split signals into the interferometer in opposite directions, combining and detecting the signals counter-propagated in the interferometer, and detecting the refractive index coefficient of the optical fiber in accordance with the difference between the two signal powers determined by a control beam. The quasi-static phase shift of the signal beam counter-propagating the same paths of the interferometer is induced by rotating the optical fiber loop of the interferometer. The present invention gives rise to little error because it does not require precise information about the pulse width of a used beam or a high-power light.

Abstract: An optical fiber laser is disclosed capable of generating an ultrashort pulse which has intensive energy and is stable against polarization by using a sagnac loop mirror and a Faraday rotator mirror, which includes a light pumping laser diode; an erbium doped fiber-added optical fiber; a wavelength division multiplier fiber coupler; a dispersion shifted fiber; and an optical fiber directional coupler; a nonlinear amplifier loop mirror; a second polarization controller; a linear mirror having a Faraday rotator mirror for rotating the polarization plane of a proceeding light wave; and a directional coupler being connected between the nonlinear amplifier loop mirror and the linear mirror.

Abstract: An all-optical signal processing apparatus of a non-linear fiber loop mirror type comprises a very high-speed all-optical switch that can be used as a reverse multiplexed switch in a high-speed time division optical communication. The apparatus includes a non-linear loop mirror for switching signal light by adjusting light using the non-linear effect of an optical fiber and the characteristics of a sagnac interferometer as the fundamental configuration. The all-optical switch is constructed so that another adjustment light having an appropriate time delay with respect to an existing adjusting light is additionally introduced in order to compensate for the limitation on the switching bandwidth imposed by the walk-off between adjusting and signal lights in a conventional non-linear optical fiber loop mirror. This compensates for the cross-talk of the noise signals due to DC components generated in the conventional apparatus.

Abstract: A wavelength-varying multi-wavelength optical filter laser using a single pump light source is disclosed.

Abstract: The present invention relates to planar integration of an optical system. The optical system is an integration of a crossover switching network having several optical elements such as mirrors, lenses, beam splitters etc., spatially separated on a single wafer using an acute-angle prism array disposed on the surface of a substrate in which the optical elements are integrated.