Abstract: Apparatus for monitoring the output of an optical system. The apparatus comprises first and second fibre optic sections, a reflective coating, and a detector. The first fibre optic section has a first cladding and a first core, and is configured to receive light from the optical system at one end and has at the other end a first angled, polished face. The second fibre optic section has a second cladding and a second core, and has at one end a second angled, polished face. The first and second fibre optic sections are arranged such that the first and second angled, polished faces are substantially parallel and adjacent and the first and second cores are substantially aligned. The reflective coating is applied to the first or second angled, polished face, and is configured to reflect a portion of light transmitted through the first core. The detector is arranged to receive the reflected light.

Abstract: There is described an interferometer for use in an optical locker. The interferometer comprises at least two transparent materials having different thermal path length sensitivities. The interferometer is configured such that an input beam is split by the interferometer into first and second intermediate beams, which recombine to form an output beam, the first and second intermediate beams travelling along respective first and second intermediate beam paths which do not overlap. At least one of the intermediate beam paths passes through at least two of the transparent materials. A length of each intermediate beam path which passes through each transparent material is selected such that an optical path difference between the first and second intermediate beam path is substantially independent of temperature.

Abstract: There is described an interferometer for use in an optical locker. The interferometer comprises at least two transparent materials having different thermal path length sensitivities. The interferometer is configured such that an input beam is split by the interferometer into first and second intermediate beams, which recombine to form an output beam, the first and second intermediate beams travelling along respective first and second intermediate beam paths which do not overlap. At least one of the intermediate beam paths passes through at least two of the transparent materials. A length of each intermediate beam path which passes through each transparent material is selected such that an optical path difference between the first and second intermediate beam path is substantially independent of temperature.

Abstract: A device and method for controlling light by wavelength in a device with a switch plane and a dispersion plane uses optics providing an imaging function in the dispersion plane, and a Fourier transform function in the switch plane, so as to enable crosstalk to be reduced.

Abstract: Methods and apparatus for use in coherent transmission and reception of optical data signals. An integrated optics block (100) for use in a coherent optical transmitter comprising: a beam splitter (102) configured to split an input light signal into first and second input light signals, to output the first input light signal for use in an optical transmitter chip and to output the second input light signal for use as a local oscillator signal; a polarization combiner (104) configured to combine first and second received modulated light signals to form an output; and a polarization rotator (106) configured to rotate the polarization of the second modulated light signal such that it is substantially orthogonal to the polarization of the first modulated light signal prior to combining.

Abstract: Methods and apparatus for use in coherent transmission and reception of optical data signals. An integrated optics block (100) for use in a coherent optical transmitter comprising: a beam splitter (102) configured to split an input light signal into first and second input light signals, to output the first input light signal for use in an optical transmitter chip and to output the second input light signal for use as a local oscillator signal; a polarisation combiner (104) configured to combine first and second received modulated light signals to form an output; and a polarisation rotator (106) configured to rotate the polarisation of the second modulated light signal such that it is substantially orthogonal to the polarisation of the first modulated light signal prior to combining.

Abstract: The invention relates to a beam combiner for a Raman pump unit. The beam combiner is configured to receive and propagate at least two orthogonally polarized collimated light beams. The beam combiner comprises a birefringent prism and an optically isotropic prism. Each of the prisms is located in the path of the beams and configured so that the beams are substantially parallel to each other when they emanate from the beam combiner.

Abstract: An assembly includes an etalon assembly for dynamically locking a frequency of an optical beam to a set frequency, the etalon assembly being external to a laser source assembly that outputs the optical beam. The etalon assembly includes an etalon that receives the optical beam and generates via interference effects a transmission beam, the etalon having a thermal tuning range greater than one half of a free spectral range of the etalon. The etalon assembly also includes an etalon heater mounted to the etalon such that the etalon heater is configured to adjust the temperature of the etalon. The assembly includes a controller configured to retrieve calibration data based on the set frequency, calculate a set temperature for the etalon using a thermal tuning algorithm and the calibration data, and control the etalon heater such that the etalon has a temperature equal to the calculated set temperature.

Abstract: The invention relates to a beam combiner for a Raman pump unit. The beam combiner is configured to receive and propagate at least two orthogonally polarised collimated light beams. The beam combiner comprises a birefringent prism and an optically isotropic prism. Each of the prisms is located in the path of the beams and configured so that the beams are substantially parallel to each other when they emanate from the beam combiner.

Abstract: Optical devices are disclosed consisting of optical chips (planar lightwave circuits) which have optically symmetric or matching designs and properties and optical components which create asymmetry in the optical devices. The devices find application in detection in coherent and non-coherent optical communications systems.

Abstract: An assembly includes an etalon assembly for dynamically locking a frequency of an optical beam to a set frequency, the etalon assembly being external to a laser source assembly that outputs the optical beam. The etalon assembly includes an etalon that receives the optical beam and generates via interference effects a transmission beam, the etalon having a thermal tuning range greater than one half of a free spectral range of the etalon. The etalon assembly also includes an etalon heater mounted to the etalon such that the etalon heater is configured to adjust the temperature of the etalon. The assembly includes a controller configured to retrieve calibration data based on the set frequency, calculate a set temperature for the etalon using a thermal tuning algorithm and the calibration data, and control the etalon heater such that the etalon has a temperature equal to the calculated set temperature.

Abstract: The present invention discloses an optical fibre (20) for coupling to an optical source (18) which includes a core (22) and a tip portion (36). The core (22) is for receiving light directed from the optical source along an optical axis; wherein the core is expanded near one end of the optical fibre, and the expanded core (24) having a diameter larger than other portions of the core that are not expanded. The tip portion (36) is on the end of the optical fibre, wherein the tip portion further includes an endmost face (26), the endmost face being non-perpendicular to the optical axis. A coupling system including such an optical fibre and a method of fabricating a coupling device for the optical fibre are also disclosed. The optical fibre as provided by the present invention not only enables high coupling efficiency with different laser mode sizes, but also reduces the back reflected laser from the optical fibre which may otherwise damage the laser semiconductor chip.

Abstract: Optical devices are disclosed consisting of optical chips (planar lightwave circuits) which have optically symmetric or matching designs and properties and optical components which create asymmetry in the optical devices. The devices find application in detection in coherent and non-coherent optical communications systems.