Lightel Technologies, Inc.

Hongyu Hu

Shyh-Chung Lin

Yong Mao

A compact tunable optical true time delay consists of an optical subassembly to apply dispersion-free time delay to the input optical signal, and a mechanical subassembly to facilitate tuning the delay using a linear actuator. The deployment of a precision optical ferrule sliding in a precision split sleeve offers a self-contained and inexpensive method to minimize optical misalignment during the tuning process, which releases the burden of the mechanical subassembly and is also advantageous in keeping the device compact. The exterior dimension remains unchanged at any moment despite the interior motion. Both reflection-type and transmission-type optical time delays are introduced, driven either manually or electrically.

Compact tunable optical time delay

An optical isolator device with minimized polarization mode dispersion includes a first polarization splitter/combiner, a non-reciprocal polarization rotator and a second polarization splitter/combiner. Only forward propagation of light is allowed to propagate in the device, with backward optical signal blocked due to non-reciprocal polarization rotation. The optical paths of o-ray and e-ray are arranged to achieve equal optical path lengths, which makes polarization mode dispersion minimal to nonexistent. When symmetrically configured, both polarization mode dispersion (PMD) and polarization dependent loss (PDL) become zero in principle.

Optical isolators

A simple, compact and low-cost passive optical transceiver device with four terminals may be used in an optical transmission system with polarization-diversity coherent detection scheme. The transceiver is composed of a first polarization splitter/combiner, a non-reciprocal polarization rotator and a second polarization splitter/combiner. The device simultaneously operates as a transmitter and a receiver with optical signals propagating along opposite directions wherein non-reciprocal polarization rotation leads to distinct effects. The received optical signal is thus split into two orthogonal polarization components directed towards two separate ports.

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Renton, WA, United States of America

Hongyu Hu