摘要:
An optical multi/demultiplexing circuit includes at least one phase generating optical coupler and an optical delay line coupled to the phase generating optical coupler. The phase generating optical coupler consists of at least one input and at least two outputs. At least one of the phase generating optical coupler has a wavelength dependent or frequency dependent output phase difference in the passband of the circuit so that it can change the transmittance characteristics of the optical multi/demultiplexing circuit.
摘要:
The present invention discloses an interferometer optical switch that can carry out switching over a broad band and has a high extinction ratio and large fabrication tolerance. The interferometer optical switch employs a phase generating coupler, the phase difference of the output of which has wavelength dependence, as at least one of the optical multi/demultiplexing device included in the interferometer optical switch. A wavelength insensitive interferometer optical switch is implemented by making the sum 2π{φ1(λ)+φΔL(λ)+φ2(λ)} constant regardless of the wavelength, where φ1(λ) is the phase produced by the first optical multi/demultiplexing device, 2πφΔL(λ) is the phase difference of the optical delay line with an optical path length difference of ΔL, and 2πφ2(λ) is the phase produced by the second optical multi/demultiplexing device.
摘要:
The present invention discloses an interferometer optical switch that can carry out switching over a broad band and has a high extinction ratio and large fabrication tolerance. The interferometer optical switch employs a phase generating coupler, the phase difference of the output of which has wavelength dependence, as at least one of the optical multi/demultiplexing device included in the interferometer optical switch. A wavelength insensitive interferometer optical switch is implemented by making the sum 2π{φ1(λ)+φΔL(λ)+φ2(λ)} constant regardless of the wavelength, where φ1(λ) is the phase produced by the first optical multi/demultiplexing device, 2πφΔL(λ) is the phase difference of the optical delay line with an optical path length difference of ΔL, and 2πφ2(λ) is the phase produced by the second optical multi/demultiplexing device.
摘要:
A planar lightwave circuit is provided. The planar lightwave circuit includes a waveguide and a spotsize converter which is a part of the waveguide, wherein a core is embedded in a cladding in the waveguide, and the spotsize converter is located near an end face of a substrate on which the planar lightwave circuit is formed, the spotsize converter including: a core width fine-tuning part in an end face side of the substrate; and a core width converting part which follows the core width fine-tuning part; wherein core width of the spotsize converter is minimum at an end face of the substrate, a mean taper angle θ1 of the core width fine-tuning part is larger than 0° and smaller than a mean taper angle θ2 of the core width converting part.
摘要:
It is an object of the present invention to reduce the size of a circuit and the adverse effects of fabrication errors, while increasing yield. Signal light incident on a circuit through input waveguides propagates from the exterior to interior of the circuit while rotating counterclockwise. The signal light passes through a point of inflection in the center of the circuit, subsequently propagate clockwise from the interior to exterior of the circuit, and then exit output waveguides. Two arms constituting a delay circuit and optical couplers can be integrated together at such an interval that they are not coupled together. Therefore, the size of the circuit can be reduced compared to the prior art.
摘要:
A interferometer type polarization beam combiner and splitter, which can combine or split polarized light over a wide band, is provided. The interferometer type polarization beam combiner and splitter includes: an optical splitter; an optical coupler; an optical path length difference imparting unit, which includes a plurality of optical waveguides arranged between the optical splitting unit and the optical coupling unit; one or two input/output ports connected to the optical splitter; and two input/output ports connected to the optical coupler. A half-integer of a wavelength of λc is set as a normalized phase difference, for the optical path length difference imparting unit, between two polarization states, and means for generating a difference in refractive index dispersion is provided between the optical waveguides of the optical path length difference imparting unit, so that the change rate of the transmittance with respect to wavelength is suppressed for the two polarization states.
摘要:
A interferometer type polarization beam combiner and splitter, which can combine or split polarized light over a wide band, is provided. The interferometer type polarization beam combiner and splitter includes: an optical splitter; an optical coupler; an optical path length difference imparting unit, which includes a plurality of optical waveguides arranged between the optical splitting unit and the optical coupling unit; one or two input/output ports connected to the optical splitter; and two input/output ports connected to the optical coupler. A half-integer of a wavelength of λc is set as a normalized phase difference, for the optical path length difference imparting unit, between two polarization states, and means for generating a difference in refractive index dispersion is provided between the optical waveguides of the optical path length difference imparting unit, so that the change rate of the transmittance with respect to wavelength is suppressed for the two polarization states.
摘要:
A Mach-Zehnder interferometer circuit (700) is provided with two couplers (722, 724) and two arm waveguides (706, 708) connecting the couplers with each other, each fabricated on a substrate, in which a polarization rotation device (732) is disposed in a groove dividing each of the two arm waveguides into two, the polarization rotation device (732) for converting vertically polarized light into horizontally polarized light, and birefringence is adjusted by performing laser irradiation or the like partially into at least one of the two arm waveguides such that a difference between birefringence values divided by an optical wavelength to be used is within a range of 2 m-0.2 to 2 m+0.2 (m is an integer including zero), the birefringence values being those integrated linearly along the respective two arm waveguides in an optical signal travelling direction.
摘要:
A Mach-Zehnder interferometer circuit (700) is provided with two couplers (722, 724) and two arm waveguides (706, 708) connecting the couplers with each other, each fabricated on a substrate, in which a polarization rotation device (732) is disposed in a groove dividing each of the two arm waveguides into two, the polarization rotation device (732) for converting vertically polarized light into horizontally polarized light, and birefringence is adjusted by performing laser irradiation or the like partially into at least one of the two arm waveguides such that a difference between birefringence values divided by an optical wavelength to be used is within a range of 2m−0.2 to 2m+0.2 (m is an integer including zero), the birefringence values being those integrated linearly along the respective two arm waveguides in an optical signal travelling direction.
摘要:
It is an object of the present invention to provide an optical filter which allows parameters to be easily adjusted, which allows birefringence and temperature dependence to be easily compensated for, and which is essentially free from dispersion. The optical filter includes an optical coupler that splits light into two beams, optical couplers connected to outputs of the optical coupler, a first group of two optical waveguide delay lines connected to the coupler, a second group of two optical waveguide delay lines connected to the coupler, an optical coupler that combines lights from the first group of the lines, an optical coupler that combines lights from the second group of the lines, and a multimode interference optical coupler that combines lights from the couplers together.