Lucent Technologies Inc.

At+t Corp.

Bell Telephone Laboratories

At&t Bell Laboratories

Agere Systems Guardian Corp.

American Telephone and Telegraph, Co.

Triquint Technology Holding Co.

Fridolin L Bosch

Clarence Burke Swan

Ton V Nguyen

James Kevin Plourde

Timothy Butrie

Rao Yelamarty

Stephen James Salko

Bryon L Kasper

Hui Fu

Thomas James Miller, Jr

Shaun P Scrak

Gregory C Salvador

Gay Leon Dybwad

George Edward Andrews

Leo Anthony Procida

Timothy P Bock

An uncooled, through-hole configured laser module adapted to receive and transmit RF signals to a laser at bandwidths from direct current (DC) to about ten gigahertz. The laser module incorporates an option for two pin-out configurations. One pin-out configuration has one ground pin and one signal pin for operation at about one gigabit/second or one gigahertz. The second high performance pin-out uses two ground pins and one signal pin for operation up to about ten gigabit/second or ten gigahertz.

Uncooled universal laser module

An electronic package is adapted to be coupled in a single-ended configuration and in a differential configuration. The package provides a characteristic impedance of approximately 50 ohms when configured in a single-ended mode and also when configured in the differential mode. The package includes multiple terminals, which are coupled to ground, S, and {overscore (S)}. The package may be configured externally by the user for either mode. The package may also be fabricated to be coupled in either the differential mode or single-ended mode for user specific applications.

Optical package with dual interconnect capability

A digital driver circuit with increased maximum output voltage amplitude and therefore also increased maximum current amplitude for constant power supply voltages is provided. A current sensing resistor replaces the conventional current source transistor in the output stage of the driver circuit. In addition, the output current control circuit is applied to an earlier stage of the driver. An automatic output current control scheme is created which keeps the voltage across the current sensing resistor equal to a DC reference and therefore maintains the output current or voltage amplitude by actively level shifting the DATA and DATA drive signals for the output stage to the correct level. This eliminates the necessity to incorporate a voltage safety margin and simultaneously increases the maximum available output voltage amplitude. Therefore, by utilizing the current sensing resistor and by moving the output amplitude control circuit to an earlier stage of the driver circuit, the driver circuit of the present invention provides increased output voltage and current amplitudes to drive modulated devices. In another embodiment, the automatic output amplitude control scheme is created by keeping the voltage across the current sensing resistor equal to a Mark-Bar reference signal corresponding to input data.

Digital driver circuit

A laser transmitter that includes a heating element coupled to the laser package and controlled to allow the laser to be kept at a higher temperature than ambient when low temperature extremes occur, thus limiting the range of wavelengths output by the laser over a given temperature range. The laser transmitter includes a semiconductor laser having an associated operating temperature; a laser driver circuit coupled to the semiconductor laser to control a modulation current and bias current conducted by the semiconductor laser; a heating element thermally coupled to the semiconductor laser; and a heating control circuit that (i) senses a temperature substantially representative of the ambient temperature surrounding the laser transmitter, (ii) energizes the heating element to provide heat to the semiconductor laser only when the temperature substantially representative of the ambient temperature is sensed below a predetermined minimum temperature, and (iii) upon energizing the heating element, controls heating of the heating element based on the temperature substantially representative of the ambient temperature.

Wide temperature range uncooled lightwave transmitter having a heated

An amplitude control scheme for a high bit rate digital optical transmitter is disclosed. The data to be transmitted by the laser is pulse-width modulated by a low frequency signal. The pulse-width modulated signal is applied to the laser via a laser driver and to a mark density reference generator. The magnitude of the low frequency components from the mark density reference generator is a signal indicative of the desired amplitude of the laser light pulses. A back-face photodiode converts a portion of the laser light into an electrical signal, the magnitude of the low frequency portion thereof being a signal indicative of the actual amplitude of the laser light pulses. The actual amplitude of the laser light pulses is compared to the desired amplitude and the laser driver output amplitude may then adjusted to compensate for variations in the laser performance.

Amplitude detection scheme for optical transmitter control

An amplitude control scheme for a high bit rate digital optical transmitter is disclosed. The data to be transmitted by the laser is pulse-width modulated by a low frequency signal. The pulse-width modulated signal is applied to the laser via a laser driver and to a mark density reference generator. The magnitude of the low frequency components from the mark density reference generator is a signal indicative of the desired amplitude of the laser light pulses. A back-face photodiode converts a portion of the laser light into an electrical signal, the magnitude of the low frequency portion thereof being a signal indicative of the actual amplitude of the laser light pulses. The actual amplitude of the laser light pulses is computed to the desired amplitude and the laser driver output amplitude may then adjusted to compensate for variations in the laser performance.

Method for controlling the amplitude of an optical signal

A technique for increasing the number of manufactured laser transmitters which meet a predetermined wavelength specification is disclosed. Semiconductor lasers which exhibit a relationship between operating temperature and wavelength can be tuned by adjusting the operating temperature to ensure that the transmitter's operating wavelength will fall within the system-specified limits.

Technique for improving the percentage of semiconductor lasers usable

Disclosed is means for driving a laser whereby a dc bias current is supplied to keep the laser normally above threshold, and a modulation current brings the laser below threshold when a pulse appears. In one embodiment, a feedback controlled bias current source (11) and modulation current source (15) are coupled to the p-side terminal of the laser (10) while a constant voltage source (27) is coupled to the n-side terminal of the laser in a way which results in subtraction of the modulation current from the dc bias current. This mode of operation essentially eliminates laser overshoot and more nearly equalizes rise and fall times of the light pulses.

Laser driving means

A system for improving performance of lasers in optical digital systems. This is accomplished by superimposing a microwave modulation current on the normal digital signal input. In the case of single mode lasers, this results in essential elimination of modal noise without any eye margin degradation. In the case of multimode lasers, the superimposed signal obviates various nonlinearities in the light output versus current characteristic which can cause eye margin degradation.

Laser digital transmitter

The timing pattern of incoming pulses is modified by amplifying the pulses, selectively shifting the dc potential of the amplified pulses, and clipping or slicing the amplified pulses at a predetermined potential. The thus clipped or sliced output pulses have a predetermined timing pattern at a predetermined dc level,resulting in a time pattern correction of the incoming pulses.

Growing community of inventors

Bethlehem, PA, United States of America

Fridolin L Bosch