Abstract: A passive optical network for transmitting digital signals incorporates sub-octave filters for the removal of distortions introduced into the signals as they are transmitted over the fiber optic cable of the network. Stated differently, second order distortions that result when the light beam carrying the digital signals is passed through a fiber optic cable are removed by the sub-octave filter. Further, the employment of another passive optical network on the same fiber optic cable with the present network is provided for. And, considerations for ensuring the compatibility of upstream and downstream transmission frequencies with the sub-octave filters are disclosed.

Abstract: A system and method are provided for controlling the transmission of RF signals that are to be carried as optical signals over an optical fiber network. Operationally, the optical signals are transmitted as “bursts” in accordance with a standard protocol. For the present invention, transmission control requires an ON/OFF control that incorporates a time delay. Specifically, a “burst” of signals (RF/optical) is initiated when power in the RF input signal passes a predetermined threshold. After an established turn-on time that is set by the time delay, the ON/OFF control activates a laser diode for transmission of the “burst.” Further, the present invention provides control for constant optical output power from the laser diode. Importantly, the laser diode is OFF when a “burst” is not being transmitted.

Abstract: Techniques and system implementations for fiber optic transmission systems for suppressing fiber induced distortions and modulation-induced distortions as well as increasing the link power and RF gain.

Abstract: Techniques and system implementations for fiber optic transmission systems for suppressing fiber induced distortions and modulation-induced distortions as well as increasing the link power and RF gain.

Abstract: Techniques and systems for reducing nonlinear distortions in an output optical beam from an optical transmitter by using both electrical pre-distortion compensation and optical compensation.

Abstract: Techniques and systems for reducing nonlinear distortions in an output optical beam from an optical transmitter by using both electrical pre-distortion compensation and optical compensation.

Abstract: A method and apparatus for optically clocked optoelectronic track and hold (“OCOETH”) device. The OCOETH device includes a diode bridge, input node, at least two current sources and at least two photodetectors. The input node is operatively coupled to the diode bridge and can receive an analog input signal. The at least two current sources are operatively coupled to the diode bridge and can forward bias the diode bridge. The at least two photodetectors are operatively coupled to the diode bridge and can receive an optical input clocking signal, and can reverse bias and forward bias the diode bridge in response to the optical input clocking signal. The hold capacitor is operatively coupled to the diode bridge and can track the analog input signal when the diode bridge is forward biased, and can hold the analog input signal when the diode bridge switches from forward biased to reverse biased.

Abstract: A dynamic range extender for optical transmitters comprises a bipolar distortion compensator for increasing drive signal gain as the absolute level of an input signal increases beyond a selected input voltage threshold, a signal coupler for dividing the input signal into complementary signals, a unipolar distortion compensator for increasing drive signal gain of each complementary signal beyond a selected forward current threshold, a signal clipper for pre-clipping each complementary signal below a selected clipping threshold, and complementary driver outputs to drive each of a pair of laser diodes in a complementary push-pull arrangement. The pre-clipping prevents the laser diodes from being driven below their threshold current level, and the distortion compensation suppresses second and third order harmonic distortion when the complementary signals generated by the laser diodes are combined by differential photodiodes.

Abstract: A method for linearizing optical transmission systems that includes an optical linearizer connected to the output of the optical transmitter. From the output, which includes a modulated signal and a transmitter distortion, the linearizer interacts with the wavelength chirping (d&lgr;c) of the transmitter output. More specifically, the linearizer is characterized by a wavelength dependent optical transfer curve F(&lgr;) that utilizes d&lgr;c to induce a compensation distortion. Further, the optical transfer curve F(&lgr;) has a reference wavelength (&lgr;p) and an operating point wavelength offset (&Dgr;&lgr;b). In operation, (&lgr;p+&Dgr;&lgr;b) of the optical transfer curve F(&lgr;) is aligned with (&lgr;c) of the output to establish an effective value for the compensation distortion. This compensation distortion is then added with the transmitter distortion to cancel the transmitter distortion from the modulated signal; to thereby linearize the output.

Abstract: A method for linearizing optical transmission systems that includes an optical linearizer connected to the output of the optical transmitter. From the output, which includes a modulated signal and a transmitter distortion, the linearizer interacts with the wavelength chirping (d&lgr;c) of the transmitter output. More specifically, the linearizer is characterized by a wavelength dependent optical transfer curve F(&lgr;) that utilizes d&lgr;c to induce a compensation distortion. Further, the optical transfer curve F(&lgr;) has a reference wavelength (&lgr;p) and an operating point wavelength offset &Dgr;&lgr;b. In operation, (&lgr;p+&Dgr;&lgr;b) of the optical transfer curve F(&lgr;) is aligned with (&lgr;c) of the output to establish an effective value for the compensation distortion. This compensation distortion is then added with the transmitter distortion to cancel the transmitter distortion from the modulated signal; to thereby linearize the output.

Abstract: An optoelectronic switch for switching an input signal comprises two PIN des connected in series with opposed polarity, an input signal choke connected to the PIN diodes for presenting a high impedance to the input signal and a low impedance to a PIN diode bias, and a photovoltaic cell connected to the PIN diodes and the input signal choke for generating the PIN diode bias to switch the PIN diodes between a substantially conductive state while the photovoltaic cell receives optical energy from a light source and a substantially non-conductive state while the photovoltaic cell does not receive optical energy from the light source.

Abstract: A resonant driving circuit for a laser diode comprises an impulse generator for generating narrow output pulses, a delay line for generating a composite output of reflections of the output pulses from terminations of the transmission line, a laser diode for generating an optical output from the composite output, and a forward bias network to bias the laser diode.

Abstract: The optoelectronic switch of the present invention comprises two PIN diodes onnected in series with opposed polarity having their intrinsic regions coupled to a light source for maintaining both diodes in the conductive state while the light source is on and in the non-conductive state while the light source is off.

Abstract: A novel bridge type optoelectronic (OE) sample and hold circuit based upon current steering demonstrates a clear superiority in performance with respect to a direct OE sample and hold circuit. The bridge type OE sample and hold circuit permits a high-speed signal to be sampled with high accuracy to offer high charging capability, commanding signal isolation, reduced time jitter and reduced holding charge leakage which are distinct advantages over conventional electronic sample and hold circuits.