Abstract: A telecommunications system that includes an external memory, an internal memory and a system clock. A boot component is configured to use the clock signal generated by the system clock to load data from external memory into internal memory when the telecommunication system operates in initialization mode. The telecommunication system is configured to operate based on the loaded data in internal memory when the system operates in normal mode. Once the initialization mode is complete, the system clock may be shut down since the telecommunication system does not need the system clock to perform normal mode operations. Subsequently, the system clock may be restarted if need be. Accordingly, the system clock is generated when it is needed, but not continuously. Therefore, cross-talk between the system clock and the receive and transmit path is reduced.

Abstract: Systems and methods for continuously compensating a modulation current of a laser. A temperature compensation circuit has circuitry with a positive temperature coefficient connected with circuitry having a negative temperature coefficient. The temperature compensation circuit generates a temperature dependent reference current that is mirrored to a gain circuit. The gain circuit provides variable gain. The gain circuit also provides inputs that can be set to select a particular gain. The output of the gain circuit, which changes as temperature affects the reference current, is used to compensate the modulation current of the laser.

Abstract: A laser driver circuit with signal transition enhancement is disclosed. The laser driver circuit comprises a pair of laser driver input terminals, a current modulator circuit, a transition boost circuit, and a nonlinear integrator circuit. The pair of laser driver input terminals are configured to receive a pair of differential input signals. The current modulator circuit generates a pair of current modulator output signals in accordance with the pair of differential input signals. The transition boost circuit generates a pair of transition boost signals for enhancing signal transitions of the pair of current modulator output signals. The nonlinear integrator circuit integrates the pair of transition boost signals to generate a pair of differential current output signals.

Abstract: An optical transceiver in which one or more bias currents provided to the laser driver are adjusted at cold temperatures such that transition speeds are reduced. A preliminary current generation circuit generates a preliminary current. In addition, a programmable cold temperature bias current compensation circuit draws a configurable amount of current from the preliminary current if the ambient temperature is below a threshold temperature to generate a final current. A laser driver bias current delivery circuit then provides at least one laser driver bias current to the laser driver. These delivered bias currents are dependent at least in part upon the final current. Accordingly, the bias currents provided to the laser current reduce the transition speed of the optical signal at low temperatures, thereby reducing jitter and electromagnetic interference, and allowing user control over the amount of compensation.

Abstract: A method of filtering a differential signal. The method includes receiving the differential signal. Transitions of the differential signal are accelerated after the differential signal has passed through a cross-over point to create an accelerated differential signal. A delayed differential signal is created that is a delayed version of the accelerated differential signal delayed by a predetermined amount of time with respect to the accelerated differential signal. The accelerated differential signal is amplified to create an amplified accelerated differential signal. The delayed differential signal is amplified to create an amplified delayed differential signal. The amplified delayed differential signal and the amplified accelerated differential signal are combined to create an output signal.

Abstract: A laser driver circuit for reducing electromagnetic interference is disclosed. The laser driver circuit includes a first differential amplifier circuit, a second differential amplifier circuit and a glitch smoothing circuit. The first differential amplifier circuit is coupled to a pair of differential input signals, and is configured to generate a first amplified signal. The second differential amplifier circuit is coupled to the pair of differential input signals, and is configured to generate a second amplified signal. The first and second amplified signals together form a differential pair of output signals. The glitch smoothing circuit has a first output terminal coupled to the first differential amplifier circuit and a second output terminal coupled to the second differential amplifier circuit. The glitch smoothing circuit is configured to reduce glitches on the differential pair of output signals when the pair of differential input signals switch states.

Abstract: A laser filter circuit includes an input terminal configured to receive an input laser signal and a first filter chain configured to generate a filtered signal. The first filter chain is coupled to the input terminal and has one or more filters connected in series. Each filter includes one or more adjustable capacitor networks. An adjustable capacitor controller generates one or more capacitor switch control signals based on an operating frequency of the input laser signal. The one or more control signals are for adjusting the capacitance of the one or more adjustable capacitor networks in the first filter chain. A plurality of output terminal output the filtered signal from the first filter chain.

Abstract: An eye safety detection circuit for use in a laser transmitter. The eye safety detection circuit shuts the laser down if the laser is emitting excessive optical energy to the point of being unsafe to a user. The eye safety detection circuit includes a laser current detection circuit that is configured to detect when there is a potential that the laser is emitting light at levels that exceed a predetermined threshold. If the laser were to immediately turn off under this condition, the laser may be turned off prematurely. Instead, the eye safety detection circuit includes a timer circuit that causes the laser to cease operation only after one or more such conditions have been met for a predetermined period of time.

Abstract: Systems and methods for regulating a current mirror. A current mirror includes mirror circuits that each include a transistor or a transistor network. A mirror circuit in the current mirror is used by a detector of an optical receiver to draw current in response to an incident optical signal on the photodiode. The transistor in the current mirror is connected with a regulating amplifier that drives a gate of the transistor. The regulating amplifier uses the drain voltage of the transistor as an input such that the amplifier's output drives the gate such that the drain voltage substantially matches a reference voltage that is also an input to the regulating amplifier. The regulating amplifier can be integrated with the current mirror and eliminates the need for an external capacitor to reduce the effects of noise on current drawn by the detector.

Abstract: First, second and third pole tip components of a write head are formed with the second pole tip located between the first and third components and a write gap layer located between the first and second pole tip components. The second pole tip is formed with a width that defines a track width of the write head. The third pole tip component is formed with top and bottom surfaces wherein the bottom surface interfaces a top surface of the second pole tip component and has a width equal to the track width and wherein the top surface of the third pole tip has a width greater than the track width.

Abstract: The present invention concerns at least an antiferromagnetic layer, which is in direct contact with a ferromagnetic layer for inducing an exchange bias in the ferromagnetic layer. Thus, the ferromagnetic layer is pinned by the antiferromagnetic layer, also referred to as the pinning layer. The antiferromagnetic or pinning layer comprises a compound from the group of orthoferrites, which show a variety of advantages. For example, these antiferromagnets can have a Néel temperature TN ranging from at least 623 K to 740 K depending on the compounds, and they can display a weak ferromagnetic moment. Therefore, a magnetic device comprising the mentioned structure can be used properly in an environment of a high operating temperature. The compound can be described by the formula RFe1−xTMxO3with R a rare earth element or Yttrium, and TM a transition metal which can be one element of the groups IB to VIII.