An optical assembly, such as a multiple output diode laser pump source for EDFAs, is formed by pressing an optical array emitter chip against a standoff structure protruding from a submount such that the emitter chip deforms to match the curvature of the standoff structure. An IO chip is also juxtaposed against the standoff structure such that its optical receivers can receive optical energy from the emitter chip. The IO chip can provide various optical functions, and then provide an optical array output for coupling into an optical fiber array. The standoff structure preferably contacts the emitter chip over an aggregate contact area much smaller than the area by which the emitter chip overlaps the submount. The materials used for bonding the emitter chip and the IO chip to the submount are disposed in the recesses between standoffs and not on the contact surfaces of the standoff structure.

Multi-channel laser pump source for optical amplifiers

A mode converter for converting an optical signal from a first propagation mode (e.g., LP 01 ) to a second propagation mode (e.g., LP 02 ). The mode converter includes a first waveguide supporting a first mode of propagation. The mode converter also includes a second waveguide supporting a second mode of propagation. The first and second waveguides each having a group index characteristic, wherein the first group index characteristic is matched with the second group index characteristic such that electromagnetic energy propagating through the first waveguide at the first mode couples to the second waveguide at the second mode.

Broadband mode converter

Multimode fiber links suffer from intermodal dispersion, which, at high data rates, produces intersymbol interference in the received optical signal. Without signal processing or equalization, this limits the achievable data rates. We consider the combination of a spatially resolved equalizer (SRE) (in the optical domain) and forward error correction (FEC) to increase the achievable data rates and reliability on these links. Our performance results obtained with actual measured impulse responses show that SRE and FEC on a multimode fiber link enable a significant increase (about 2.5 times) in data rate and/or a reduction in bit error rate (BER) at relatively low cost. Furthermore, we show that improvements in data rate and reliability are generally not possible using FEC alone, making the SRE/FEC combination a cost-effective, attractive approach.

Spatially resolved equalization and forward error correction for multimode fiber links

An optical semiconductor device includes a semiconductor laser diode having a first electrode for receiving a current for driving the laser diode, and a grounding electrode; a modulator for modulating light emitted from the semiconductor laser diode, the modulator having a second electrode for receiving a current for driving the modulator, and a grounding electrode connected to the grounding electrode of the semiconductor laser diode; a first resistor having a terminal connected to the first electrode of the laser diode; a second resistor connected between the second electrode of the modulator and the grounding electrode of the modulator; and a third resistor having a first terminal connected to the grounding electrode of the modulator and a grounded second terminal. Therefore, the laser diode driving current can be made larger when the modulator absorbs the laser light than when the modulator does not absorb the laser light, so that the oscillating wavelength is shortened, resulting in an inexpensive optical semiconductor device that hardly degrades optical pulse transmission performance.

Optical semiconductor device

A method and corresponding apparatus is disclosed for determining a particular Optical Network Terminal (ONT) in a Passive Optical Network (PON) is malfunctioning by sending a continuous stream of light up a shared fiber, which results in adversely affecting communications between the ONT and an Optical Line Terminal (OLT). The example embodiment verifies the failure is due to a faulty optical transmitter in the ONT and not a different network fault, such as a fiber optic line cut or power outage. Through the use of the example embodiment, a service provider can determine in an automated manner which specific ONT of a PON is malfunctioning.

Methods and apparatus for identifying a passive optical network failure

A novel device and method of beam steering for semiconductor lasers or optical amplifiers is disclosed. The method of the present invention achieves high signal extinction ratios, high speed, low chirp modulation by biasing a multi-lateral mode beam steering section. The device of the present invention comprises an active single vertical and lateral mode optical waveguide, a multi-lateral mode waveguide, and a mode converter. The mode converter efficiently couples output from an active single mode waveguide to two or more modes of a multi-lateral mode waveguide. Two guided modes arrive at a device facet with a particular intermodal phase difference based on initial mode phasing, multi-lateral mode waveguide length and modal dispersion properties, and facet angle. Beam steering is achieved through carrier antiguiding effect by injecting current into the multi-lateral mode waveguide from the mode converter thus changing the intermodal dispersion. Changing the intermodal phase difference changes the direction of beam propagation relative to the device facet, providing enhanced beam steering.

Scott A. Merritt

Papers

Intermodal phase difference controller for beam angle modulation in index guided semiconductor devices