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Itf Optical Technologies Inc.

Fran&ccedil;ois Gonthier

Bruno Y Dion

Alain Villeneuve

Nicolas Godbout

Pierre Cottin

An all-fiber Mach-Zehnder interferometer has a central fiber structure in which two single-mode fibers are placed to have a desired path difference and are stabilized in such position by bonding them in certain spots. A coupler is then made on each side of the central fiber structure to produce the Mach-Zehnder effect. The combination of the central fiber structure and of the couplers at each end is mounted on a substrate and packaged to produce the interferometer.

All-fiber Mach-Zehnder interferometer and method of making the same

An optical fiber filter ( ) with a non-sinusoidal wavelength response is produced by forming an adiabatic taper in a single mode fiber ( ) and forming non-adiabatic tapers ( ) on slopes at each end of the elongated central region of this adiabatic tape and in the middle of the central region ( ). The non-adiabatic taper ( ) in the middle of the central region ( ) produces a phase shift in the wavelength response leading to non-sinusoidal filtering characteristics. The filter may be combined with a Mach-Zehnder interferometer to produce a Mach-Zehnder device with a non-sinusoidal wavelength response.

Non-sinusoidal optical fiber filters and method of making the same

Multiplexing and demultiplexing single-mode fiber optic couplers are fabricated by aligning two single-mode fibers which have been stripped of their protective plastic jackets and cleaned so that they are held in parallel contact with each other, and then fusing these fibers to achieve a desired fusion profile and elongating the fused fibers to achieve a match point between the wavelength period and the polarization phase. The elongation process is interrupted and resumed as required to obtain a precise match point required to produce the desired multiplexing or demultiplexing coupler.

Fabrication of multiplexing and demultiplexing single-mode fiber optic couplers

An all-fiber optical depolarizer is provided in which polarized light is controllably injected into a polarization beam splitter at a 45&deg; angle. The beam splitter is combined with a loop made of standard non-birefringent fiber through which one of the polarizations split by the beam splitter circulates. The loop has a length greater than the coherence length of the light source. The interaction of the beam splitter and the loop produces incoherent depolarized light at the output transmission port of the beam splitter.

All-fiber depolarizer

An optical filter is produced that has a desired spectral response. This is done by first decomposing the desired spectral response into individual simulated responses (F . . . F ) using a suitable computer program. Then tapered fiber filters are manufactured with parameters that closely match the individual responses. And finally the tapered fiber filters are concatenated on a single-mode fiber to produce the optical filter with a total response that closely matches the desired spectral response.

Optical filters and method of making the same

A temperature stabilized tapered fiber optic component is produced, such as a fiber optic coupler or a fiber optic filter. In the case of the component such as a coupler, at least two fibers are fused and tapered to achieve a desired taper profile with suitable mechanical and wavelength properties. In the case of a component such as a fiber filter, only one fiber is tapered. Once the component is formed, it is solidly secured to a rigid substrate that produces a mechanical stress such as to compensate for any modal phase shift of the component due to temperature variation. Also, the mechanical phase dependence of the component may be adjusted in relation to the substrate to provide the desired temperature compensating effect. Preferably, both these features are used to achieve the best possible temperature stabilization.

Temperature stabilization of tapered fiber optic components

A polarization-combining fused-fiber optical coupler is made of polarization maintaining (PM) fibers spliced to non-birefringent single mode (SM) fibers which are fused and drawn near the splicing to form a coupler with an adiabatic tapered profile. The linearly polarized light injected into PM fibers travels through the coupler where the power of the two polarizations is combined and transmitted to one output fiber. The method for producing such coupler involves splicing a pair of PM fibers to a pair of SM fibers, then injecting linearly polarized light into each PM fiber and fusing and drawing SM fibers to form an adiabatic coupler with maximum power transmission at a desired wavelength going to only one output fiber.

Polarization-combining fused-fiber optical coupler and method of producing the same

An optical fiber filter is produced which has a sinusoidal response or a modulated sinusoidal response with any desired amplitude and wavelength period. This is achieved by first producing an elongated adiabatic taper in a single-mode fiber which has been stripped of its protective jacket. Then, on the slope of this adiabatic taper, at each end of the central zone, there is formed a non-adiabatic taper such as to obtain a predetermined sinusoidal or modulated sinusoidal response in the filter.

Growing community of inventors

Ville Mont-Royal, Canada

François Gonthier

Growing community of inventors

Ville Mont-Royal, Canada

Fran&ccedil;ois Gonthier

François Gonthier