Mindspeed Technologies, Inc.

Macom Technology Solutions Holdings, Inc.

Daniel Draper

Maurice M Reintjes

Gilberto Isaac Sada

Keith R Jones

Cristiano Bazzani

Charles E Chang

Merrick Brownlee

Jerome Garez

Wim F Cops

Krishna Shivaram

Michael P Khaw

Kevin McDonald

Hehong Zou

Quazi Ikram

Anping Liu

Kenneth Tsui

A multi-level optical signal is sampled to generate an eye diagram. The signal can be adjusted when eyes in the eye diagram have different heights. More specifically, a first value is determined, and the height of a first eye is adjusted using the first value. The first value is multiplied by a stored factor to produce a second value, and the height of a second eye is adjusted using the second value, and so on for other eyes. As a result, eye heights are the same. Similarly, optical power levels of the signal can be adjusted when the levels are not equally spaced. As a result, the optical power levels are equally spaced.

Adjusting eye heights and optical power levels of a multi-level optical signal

An optical signal generator is configured with an associated control system and driver configured to reduce speckle. Speckle reduction occurs by pulsing the drive signal between a first current level and a second current level. These pulses force the optical signal generator to introduce oscillations into the optical signal. The coherence of the emitted light is reduced during the period of oscillations in the optical signal, which reduces speckle. In one embodiment, the pulsing of the drive signal brings the drive signal down to a level near or below threshold, which in turn intermittently turns off the optical signal output. Returning the optical signal to a desired optical output intensity introduces the speckle reducing oscillation. The pulse frequency, and duty cycle is controlled by a duty cycle control signal to modulate overall optical power and adjust amount of despeckle.

Method and apparatus for reducing optical signal speckle

The invention relates to amplifiers and in particular, to a transimpedance amplifier for high rate applications. Disclosed is a two stage transimpedance amplifier having a first stage comprising an amplifier and a load and a second stage comprising an amplifier and a resistor. Negative feedback is provided through a feedback resistor. Only two voltage conversions occur which reduces phase distortion, as compared to three stage transimpedance amplifiers which perform 3 voltage conversions.

High sensitivity two-stage amplifier

A projection system with one or more light sources reduced power consumption and optional scanning capability is disclosed. A controller processes image data to generate light source control signals and pixel screen control signals which are coordinated to generate an image. Reductions in power consumption occur by matching the light output from the light source to the brightest pixel(s) in the pixel screen for a particular frame. By setting the light output level to an intensity or duration matched to only the maximum level corresponding to a image frame, power consumption is reduced as compared to an embodiment which sets the light source output to its maximum level or maximum duration. The pixel screen, which may be an LCD screen, sets pixel areas corresponding to the brightest pixels as transparent and other, less bring pixels on the pixel screen are set to appropriate levels of reduced transparency.

Reducing power dissipation in portable LCoS/LCD/DLP projection systems

An optic signal transmit system and biasing method and apparatus and system is disclosed to reduce power consumption during non-transmit periods. An optic signal generator receives a bias signal and an outgoing signal. A burst/transmit enable signal enables the transmit system into transmit mode, such as during a transmit window in a time multiplexed environment such as PON networks. A bias circuit biases the driver and/or optic signal generator. To realize power savings, the bias circuit includes one or more stages which are selectively enabled to adequately bias the driver and optic signal generator during transmit windows but disabled during periods when the system is not transmitting. The bias circuit may comprise a current mirror with a reference device, a fixed device, and switched device, which is selectively included in the circuit by a bias switch. The bias switch is responsive to a burst/transmit enable signal or a signal related thereto.

Bias circuit for burst-mode/TDM systems with power save feature

Various circuits and methods are provided for driving a laser. A laser driver circuit is configured to generate a modulated current through a laser. Also, a peak current source is employed to generate a peak current that is differentially applied to the laser to enhance a transition rate of the laser.

Enhancing the transition rate of a laser

Various laser drivers and methods are provided. In one embodiment, a laser driver is provided that comprises a laser driver circuit having a common anode portion and a common cathode portion. The common anode portion and the common cathode portion are each configured to drive a laser. Also, the laser driver includes a control input to alternatively enable one of the common anode portion and the common cathode portion to drive the laser.

Configurable laser driver with common anode and common cathode outputs

A method and apparatus is disclosed for optic signal power control to maintain a desired or optimum optic signal power level. During start-up, a default or target value from memory may be utilized to bias or otherwise control operation of an optic signal generator or driver. During operation, pre-stored values may continue to be utilized or an open loop or closed loop control system may be utilized. An open loop control system may incorporate a temperature module or a timer module to account for changes in environment or changes due to aging that may undesirably affect system operation. A closed loop control system may incorporate one or more feedback loops that generate a compensation value to account for detected changes. In one configuration one or more peak values of the actual optic signal, or a portion thereof, are detected and processed to generate the compensation signal.

Laser power control with automatic compensation

A method and apparatus is disclosed for optic signal power control to maintain a desired or optimum optic signal power level. During start-up, a default or target value from memory may be utilized to bias or otherwise control operation of an optic signal generator or driver. During operation, one or more parameters or aspects of the optic module or the environment may be monitored. In response to the monitoring one or more control signal may be generated to created to modify bias level, modulation level, or both. The monitoring may monitor the optic signal itself. The bias level and modulation level may be changed simultaneously.

Multiple parameter laser power control with automatic compensation

A method and apparatus configured to incorporate system data for transmission as part of or concurrently with network data. The system data may comprise communication system data for use in controlling or monitoring a communication system. The system data may be is utilized to control or adjust the amplitude or intensity of the network data to thereby amplitude modulate the system data into or with the transmission of the network data. By monitoring the amplitude or intensity of the received network data signal, the system data may be recovered. An automatic gain control or bias loop may be monitored to detect the amplitude modulation of the network data. The system data may be encoded.

Module to module signaling utilizing amplitude modulation

A method and apparatus configured to transmit module data between optic modules over a primary communication channel, such as an optic fiber configured to carry network data or outgoing data. A control center may send the module data, such as any type of DDMI data, over the optic fiber to control one or more aspects of the optic module system. The optic module may also be configured to send module data regarding any aspect of module status or operation, to a control center, via the optic fiber. Use of the primary communication channel, normally reserved for only network data, allow for module to module communication or module to control center communication without need of cumbersome two wire interface or supplement channels. Optic module data communication may occur concurrent with network data transmission. Optic module data back-up may occur via the optic channel to provide rapid re-load of important optic module data.

Module to module signaling

In one system embodiment, the system is characterized by: a differential amplifier including but not limited to at least one amplifying transistor having an emitter coupled directly to a ground. In one embodiment of a method of making a system, the method is characterized by: operably coupling at least one amplifying transistor of a differential amplifier directly to a ground. In one embodiment of a method of driving a system, the method is characterized by: driving at least one amplifying transistor of a differential amplifier with an emitter-follower feedback loop. In one system embodiment, the system is characterized by: a differential amplifier including but not limited to a first amplifying transistor having a base operably coupled with a first emitter-follower feedback loop.

Driver circuits and methods

The power control system utilizing a normal average power control loop to control average power and modulation level of an optic signal generated by an optic signal generator. The target average power is adjusted by a small percentage, and the corresponding change in bias current needed to adjust the average power level is monitored. The change in average power divided by the change in bias current is a measure of the optic signal generator's slope efficiency. Modulation current is adjusted up or down based on the change in slope efficiency compared to the slope efficiency stored at the time of module calibration. By adjusting the modulation current, the desired optic signal output from the transmitter may be maintained.

Optical modulation amplitude compensation system having a laser driver with modulation control signals

A method and apparatus for signal amplification and decision device operation on a signal which has a magnitude, peak value, or other average power that varies over time. In general, a peak detector detects the peak value of a received signal and responsive to the peak value, selectively enables a decision device when the signal is amplified to increase decision device accuracy. The decision may occur before the amplification forces the signal into saturation. Multi-stage amplification in combination with controlled switching or multiplexing may be utilized to selectively amplify the signal and selectively initiate decision device operation. The peak detector value may also control signal amplification levels in a multi-stage amplifier. Responsive to the peak value, a switch, which receives as its input the output from one or more amplifier stages, may be controlled to output the signal after a desired amount of amplification.

Growing community of inventors

Portland, OR, United States of America

Daniel Draper