Opnext Patent Grants

Automatic gain control for high-speed coherent optical receivers

Granted: July 1, 2014
Patent Number: 8768178
Feed-forward and feedback strategies are used to control local oscillator power and transimpedance amplifier gain in a high-speed coherent optical receiver.

Green laser system

Granted: March 18, 2014
Patent Number: 8675698
A green laser is made by constructing a laser cavity that includes within it a laser diode, a non-linear crystal such as KTP, and a lens. The boundaries of the cavity are not defined by the ends of the diode itself, but are instead defined by the ends of an apparatus that includes the lens and the KTP or similar crystal.

Alignment of in-phase and quadrature data in quadrature phase shift keying optical transmitters

Granted: February 4, 2014
Patent Number: 8644420
I/Q data skew in a QPSK modulator may be detected by sending identical or complementary data streams to I and Q channel PSK modulators, setting the relative carrier phase between I and Q to zero or ?, and monitoring the average QPSK output power, where the data streams sent to the I and Q channels include streams of alternating ones and zeroes.

Polarization and differential-group-delay insensitive digital timing error detection for polarization-multiplexed coherent optical systems

Granted: January 21, 2014
Patent Number: 8634726
Digital timing error detection systems and techniques are described. The described techniques are independent of polarization and differential-group-delay and are used to perform timing recovery of polarization-multiplexed coherent optical systems.

Multiplexer lane alignment for high-speed data systems

Granted: October 22, 2013
Patent Number: 8565271
Patterns detected by a low-speed receiver at the output of a high-speed multiplexer are used to determine when multiplexer input lanes are deskewed.

Quadrature time skew detection for coherent optical signals

Granted: October 22, 2013
Patent Number: 8565621
A method for detecting and measuring time skew in high-speed DP-QPSK coherent optical receivers is described.

Coherent optical receiver with adaptive equalizer initialization system

Granted: September 10, 2013
Patent Number: 8532504
An adaptive-equalizer initialization system performs three functions: frequency offset estimation, taps estimation for chromatic dispersion filters, and taps initialization for an adaptive equalizer. The system contains hardware FFT and peak detector units that sense a pure tone that marks the beginning of a known, short data sequence.

Polarization monitoring in polarization division multiplexing in optical communications

Granted: May 7, 2013
Patent Number: 8437632
Systems and techniques for optical communications based on polarization division multiplexing are described.

In-phase and quadrature pattern alignment for quadrature phase shift keying optical transmitters

Granted: April 23, 2013
Patent Number: 8428183
I/Q data skew in a QPSK modulator may be detected by sending identical or complementary data streams to I and Q channel PSK modulators, setting the relative carrier phase between I and Q to zero or ?, and monitoring the average QPSK output power, where the data streams sent to the I and Q channels include pseudorandom streams of ones and zeroes.

Optical transceiver and projection covering member

Granted: November 20, 2012
Patent Number: 8313251
An optical transceiver has a projection covering member that can suppress EMI noise radiated from a pig-tail part. An elastic covering member covers a projection which includes an optical coupler of an optical sub assembly. The covering member is made of a conductive elastic material having a predetermined resistivity. At least a part of an outer circumference surface of the elastic covering member comes into intimate contact with an outer periphery of a conductive opening part of a case…

Optical transmission module, wavelength monitor, and wavelength drift detection method

Granted: September 25, 2012
Patent Number: 8275011
To detect a wavelength drift of laser light with no error, an optical transmission module (10) includes: a laser diode (20); a laser temperature calculation section (52) for detecting the temperature of the laser diode (20) that monotonously increases with respect to a wavelength of the laser light; a wavelength calculation section (44) for detecting a transmittance of the laser light incident on an etalon filter (36) whose transmittance periodically varies with respect to the wavelength…

Optical receiver having fractional sampling

Granted: August 14, 2012
Patent Number: 8244142
Apparatus and methods for receiving and processing optical signals carrying symbols that represent data, including an optical receiver having fractional sampling analog-to-digital conversion and interpolation timing recovery synchronization for processing an optical signal.

Optical transmitter device and optical transmitter module

Granted: July 10, 2012
Patent Number: 8218973
Provided are an optical transmitter device and an optical transmitter module which are capable of reducing the optical transmitter module size while maintaining a state where an excellent optical transmission waveform quality is obtained over a wide range of frequencies. The optical transmission module (2) includes a semiconductor laser diode device (10), an optical modulator device (12), and a first termination resistor circuit (14-1). A printed circuit board (4) includes a driver IC…

Optical transmitter and optical communications device

Granted: July 3, 2012
Patent Number: 8213472
Disclosed is an optical transmission module in which effects of conductive heat from sides of a metal case upon a thermistor are reduced, thereby allowing steady optical beam wavelengths to be obtained over a wide range of temperatures, regardless of the temperature of the usage environment. Specifically, the optical transmission module includes Peltier elements disposed inside a metal case, a metal base disposed upon the Peltier elements, a laser diode substrate disposed upon the metal…

Optical module

Granted: June 19, 2012
Patent Number: 8204351
Provided is an optical module including: an optical assembly incorporating a light emitting or receiving device for converting one of an electrical signal and an optical signal into another of the electrical signal and the optical signal; a circuit board electrically connected to the optical assembly; an optical fiber optically connected to the optical assembly; a tray for winding the optical fiber therein and pulling out the optical fiber therefrom; and a case receiving the optical…

Wavelength tunable filter and wavelength tunable laser module

Granted: May 15, 2012
Patent Number: 8179931
A wavelength tunable filter and a wavelength tunable laser module are a codirectional coupler type whose characteristics do not vary significantly with a process error. They are structured so as to include a semiconductor substrate which has a first optical waveguide and a second optical waveguide. The first and the second optical waveguides are extended from a first side of the semiconductor substrate to an opposing second side thereof. The first optical waveguide includes a first core…

Optical transmission circuit

Granted: March 6, 2012
Patent Number: 8131158
Provided is an optical transmission circuit capable of realizing a high-quality optical signal waveform with low power consumption. An optical transmission circuit (10) includes: a laser diode (800); a modulator (900) for supplying a differential modulation current to an anode terminal and a cathode terminal of the laser diode (800) through transmission lines (301 to 304); a current source (101) for supplying a forward bias current to the laser diode (800); and a magnetic sheet (wave…

Nitride semiconductor optical element and manufacturing method thereof

Granted: February 28, 2012
Patent Number: 8124432
In an InGaN-based nitride semiconductor optical device having a long wavelength (440 nm or more) equal to or more than that of blue, the increase of a wavelength is realized while suppressing In (Indium) segregation and deterioration of crystallinity. In the manufacture of an InGaN-based nitride semiconductor optical device having an InGaN-based quantum well active layer including an InGaN well layer and an InGaN barrier layer, a step of growing the InGaN barrier layer includes: a first…

Balanced phase-shaped binary transmission in optical communications

Granted: February 28, 2012
Patent Number: 8126337
Optical communication apparatus, methods, systems are provided based on balanced-detection phase-shaped binary transmission (BD-PSBT).

Optical receptacle, optical module, and method of manufacturing an optical module

Granted: February 21, 2012
Patent Number: 8118498
Provided are an optical receptacle capable of manufacturing an optical module thereby, while suppressing a manufacturing cost, preventing a quality degradation, and suppressing a quantity of returning light by reflection. In the optical receptacle, a recess for receiving a lens and a lens support and a through-hole penetrating from a bottom of the recess toward an exterior are formed, and the recess is formed so that an inner peripheral surface of the recess is fixed to a desired…