Abstract: Optical pulse compression is of importance in very high bit rate optical fiber communication systems. We are disclosing an adiabatic optical pulse compressor that can achieve substantial compression by means of a relatively short (e.g., about 100 cm) chirped periodic structure, exemplarily an apodized and chirped fiber Bragg grating. The input pulse to the periodic structure typically are not soliton pulses, but the passage through the periodic structure results in transformation of the pulses into substantially transform-limited soliton pulses that are available (typically after appropriate modification) for transmission through conventional optical fiber towards utilization means. The input pulses can be generated by any applicable method, e.g., by combining the cw outputs of two lasers that differ with regard to the frequency of their output.

Abstract: A tunable chromatic dispersion compensator for optical communication systems is disclosed. An optical grating, such as a fiber Bragg grating, nonchirped, linearly chirped or non-linearly chirped, is strained to alter the dispersion compensator characteristics, preferably with a gradient-generating body bonded onto the length of the fiber grating. The body may be latchably strained so that the grating characteristics may be changed or tuned while avoiding use of a continuous power supply. Various optical networking applications using such dispersion compensating devices are also disclosed.

Abstract: In accordance with the invention, an optical pulse compressor comprises a pulse source, a section of nonlinear optical waveguide including a periodic structure, such as a Bragg grating, for providing positive dispersion and a section of linear optical waveguide including a negative dispersion component. The nonlinear waveguide should have a second order index N.sub.2 at least ten times the second order index N.sub.2 ' of the linear waveguide. The nonlinear waveguide is preferably chalcogenide fiber, with a Bragg grating photoinduced into the core. Because the grating is 4-5 orders of magnitude more dispersive than standard optical fiber, the length of the nonlinear waveguide section can be scaled down to a few centimeters with accompanying reduction of deleterious processes. Modeling suggests that compression factors of 5 with an initial 60 ps pulse are achievable with grating lengths of about 20 cm.

Abstract: In accordance with the invention, a reconfigurable optical fiber grating comprises an optical fiber grating with a temperature sensitive material surrounding the cladding region or incorporated into the cladding region. One or more heating elements are arranged to produce a a temperature gradient along the length of the grating and thereby chirp the grating. In a preferred embodiment, a long period fiber grating is surrounded by a material in which dn/dT is 10 times as large as that of glass and in which n is close to but lower than that of the glass. A temperature gradient along the length of the grating results in a broadening of the resonance.

Abstract: In accordance with the invention, an optical switch employs a long-period grating for switching light between alternative optical paths. In essence, the device comprises a variable intensity light source, a length of optical waveguide dimensioned for co-propagating light in two distinguishable modes, and a long-period grating in the waveguide for coupling between the two modes. The waveguide is nonlinear so that the effective refractive index is a function of intensity. As a consequence the coupling produced by the grating is a function of intensity. Thus different levels of light intensity can switch between the separate modes. Advantageously a mode separator is provided for directing light in the two modes onto respectively different optical output paths. A variety of two-mode switches and optical limiters are described, as well as an optical system using the switch.