Abstract: A signal interface comprises a non-reciprocal device having a first port that accepts a first electrical signal and a second port that accepts a second electrical signal. The non-reciprocal device passes the second electrical signal through the first port without a phase shift and passes the first electrical signal through the second port with a 180 degrees phase shift. An optical modulator receives an optical signal at an optical input port, a second signal at a first and a second electrical input port, the first electrical signal at a third electrical input port, and the phase-shifted first electrical signal from the non-reciprocal device at a fourth electrical input port. The optical modulator transmits the second electrical signal to the first port of the non-reciprocal device without a phase shift and modulates the first electrical signal on the optical signal and providing the modulated optical signal at an optical output port of the optical modulator.

Abstract: A bi-directional signal interface includes a first waveguide that propagates a first traveling wave. The first waveguide has one end that is coupled to a RF input port that receives a RF transmission signal and another end that is coupled to a RF bi-directional port that receives a RF reception signal and that transmits the RF transmission signal. A second waveguide is positioned proximate to the first waveguide. The second waveguide has one end that is coupled to an output port that passes the received RF reception signal. A non-reciprocal coupler couples fields from the first waveguide to the second waveguide so that the RF reception signal from the bi-directional port couples from the first waveguide to the second waveguide in a substantially non-reciprocal manner and then passes through the output port, and the RF transmission signal from the RF input port passes through the first waveguide to the RF bi-directional port.

Abstract: An optical component package is disclosed. The package has a housing. The interior of the housing is adapted to house an optical component. The package includes at least two fiber optic connectors, each comprising an component side adapted to connect to the optical component and each having a pluggable exterior element. Each of the at least two fiber optic connectors are mounted in the housing with their component side accessible from the interior of the package and their pluggable exterior element accessible from the exterior.

Abstract: An arrangement has a WDT (Wavelength-Dependent Tap) coupled in an OCS (Optical Communication System) and an OPM (Optical Performance Monitoring) function coupled to the WDT. The WDT is adapted to receive from the OCS an input optical signal having noise and channels at respective channel wavelengths. The WDT couples to an output some of the input optical signal at the channel wavelengths and most of a noise power at wavelengths between the channel wavelengths, and couples a remaining portion of the input optical signal back into the optical communication system. The optical performance monitoring function determines a power characteristic of the input optical signal as a function of a power from the output. The power characteristic may be an OSNR (Optical Signal-to-Noise Ratio) determined as a function of a signal power and a noise power of the output optical signal.

Abstract: An optical amplifier system and controller and a method for automatically controlling the usable signal power of an optical amplifier are provided. The method differentiates between the total optical power that includes the amplified spontaneous emission (ASE), and the useful amplified optical signal power at the output of the amplifier. The optical amplifier system comprises an optical amplifier, a first and a second photodetector operable to measure the power of the input and output signals of the optical amplifier and an amplification controller with a control input. The amplification controller is operable to compensate for the ASE power when operating in automatic signal power control mode.

Abstract: A modulator includes an interferometer waveguide structure formed on an electro-optical substrate, preferably a Z-cut lithium niobate or a Z-cut lithium tantalate. The substrate includes a domain inversion between a region near the first arm and a region near the second arm of the interferometer waveguide structure. In one example, two coplanar strip electrode structures, each extending near at least a portion of the first arm and the second arm, respectively, are electrically coupled to each other.

Abstract: Approaches to bias control are disclosed for an optical modulator that modulates an optical carrier with a data input signal. In one embodiment an electrical bias input signal provided to the modulator is adjusted based on a characteristic of the data input signal detected from the modulated optical output signal. Another embodiment injects an additive dither signal into an optical modulator receiving a data input signal having a modulation depth of at least on the order of 50%. These embodiments can obtain and maintain a correct bias point on a modulator's transfer function curve when the modulation signal has a modulation depth on the order of 100%.

Abstract: An optical amplification apparatus is provided comprising a plurality of fiber amplification media segments which are concatenated in series wherein subsequent to each fiber amplification media segment one or more wavelengths is dropped so as to exploit a gain versus fiber amplification media physical length characteristic. By exploiting the gain versus fiber amplification media physical length characteristic in such a manner it is possible to achieve a substantially flat gain response for a multi-wavelength output of the optical amplification apparatus. Some embodiments of the invention combine noise suppression and additional gain flattening on one or more wavelengths. Embodiments of the optical amplification apparatus can be used in red-band wavelength range applications of coarse wavelength division multiplexing (CWDM). Some embodiments of the invention also provide that the optical amplification apparatus can be used as a hybrid dense wavelength division multiplexing (DWDM) and CWDM optical amplifier.

Abstract: An optical resonant modulator includes an optical ring resonator and an optical loop that is coupled to the optical ring resonator by two couplers. The optical ring resonator can have a hybrid design in which the ring resonator is formed on an electro-optically passive material and the optical loop is formed on an electro-optically active material. An amplification section can be inserted between the electro-optically passive and the electro-optically active sections. In analog applications, an optical resonator includes a Mach Zehnder interferometer section having an input and an output, with a feedback path coupling the output to the input. Applications of the optical modulator of the invention, and a method for modulating an optical signal also are disclosed.

Abstract: In the system of the present invention, two DFB laser outputs are combined in a first stage to produce a beat signal. The two main channels interfere with each other to form beat signals. This combined signal is then used as the seed to create multi-channels through optical fiber non-linearity in a multiplier stage.

Abstract: A modulator includes an interferometer waveguide structure formed on an electro-optical substrate, preferably a Z-cut lithium niobate or a Z-cut lithium tantalate. The substrate includes a domain inversion between a region near the first arm and a region near the second arm of the interferometer waveguide structure. In one example, two coplanar strip electrode structures, each extending near at least a portion of the first arm and the second arm, respectively, are electrically coupled to each other.

Abstract: New systems and methods for wavelength locking for a class of multi-wavelength laser sources (MWLS) are provided. In this type of MWLS, the set of output wavelength channels are produced from a limited number of initial laser sources, such as a single laser or dual laser. In this invention, the initial lasers are locked based on the wavelengths of the outer channels in the set of output channels to provide tighter channel locking than that of a single laser source. This is mainly possible since the error in channel spacing caused by channel wavelength offset of the seed lasers is amplified by channel multiplication done in MWLS. This provides better resolution than applying wavelength locking to the seed lasers.

Abstract: An optical resonant modulator includes an optical ring resonator and an optical loop that is coupled to the optical ring resonator by two couplers. The optical ring resonator can have a hybrid design in which the ring resonator is formed on an electro-optically passive material and the optical loop is formed on an electro-optically active material. An amplification section can be inserted between the electro-optically passive and the electro-optically active sections. In analog applications, an optical resonator includes a Mach Zehnder interferometer section having an input and an output, with a feedback path coupling the output to the input. Applications of the optical modulator of the invention, and a method for modulating an optical signal also are disclosed.

Abstract: A Mach-Zehnder interferometer having two optical couplers interconnected by two optical fibers at least one of which is temperature insensitive. In use, temperature induced changes in the geometrical length and refractive index of the temperature insensitive fibers offset each other so that the optical path length of the fiber is unaffected by the temperature change. Where two temperature insensitive fibers are included these may be of the same or of different lengths. The interferometer may be used in a Dense Wavelength Division Multiplex system.

Abstract: In the present invention a Multi-Wavelength Ring Laser Source (MWRLS) design based on Erbium Doped Fiber Laser is provided. A LiNbO3 modulator is used to extend laser channels and as mode-locking device.

Abstract: In the system of the present invention, two DFB laser outputs are combined in a first stage to produce a beat signal. The two main channels interfere with each other to form beat signals. This combined signal is then used as the seed to create multi-channels through optical fiber non-linearity in a multiplier stage.

Abstract: In this invention an optical gain element is used where a fraction of the optical output signal is passed through a periodic filter and fed back to the gain medium. This configuration simply forms a multi-wavelength ring laser. The optical gain element provides the gain medium for the laser and the filter forces the laser to lase on the predetermined wavelengths. The periodic filter can simply be an asymmetric Mach-Zehnder Interferometer (MZI). It is known that asymmetric MZIs have an almost sinusoidal wavelength response where its period is a function of the length difference of the arms of the asymmetric MZI. Therefore, channel spacing may be controlled by changing the arms length difference in an Asymmetric MZI.

Abstract: The present invention introduces a novel and simple method to adjust the MZ filter channels to those of the ITU grid. This is done through inducing an optical path length difference by using a UV light source to create a change in the index of refraction of the fiber arms after the device is packaged. The UV light is launched into the MZI filter through one of its input ports in order to achieve the phase adjustment. Since the exposure length is the entire length of one of the arms of the MZI, the required refractive index change is much smaller than the localized UV tuning of the previous methods. This allows for a weaker UV source power and shorter treatment times, thus reducing the chances of localized fiber damage.

Abstract: A Mach-Zehnder interferometer having two optical couplers interconnected by two optical fibers at least one of which is temperature insensitive. In use, temperature induced changes in the geometrical length and refractive index of the temperature insensitive fibers offset each other so that the optical path length of the fiber is unaffected by the temperature change. Where two temperature insensitive fibers are included these may be of the same or of different lengths. The interferometer may be used in a Dense Wavelength Division Multiplex system.

Abstract: A method of making an asymmetric Mach-Zehnder Interferometer (MZI) adjusts the length of the arms of two Michelson Interferometers, (MI) to achieve desired wavelength response then combines the MIs to provide the MZI. An asymmetric MZI is, therefore, provided which comprises two asymmetric MIs optically connected back-to-back.