Abstract: A multi-channel mode converter includes a lens array having a first lens and a second lens, a glass block coupled to the lens array, and a fiber assembly unit (FAU) array coupled to the glass block, the FAU array including a first fiber corresponding to the first lens, and a second fiber corresponding to the second lens. The FAU array provides for a corresponding number of fibers and lenses such that a specific single fiber corresponds to a specific single lens, there being a 1:1 relationship between fibers and lenses. A mode converter system comprises: a lens array comprising: a first silicon lens configured to convert a first mode between a first waveguide and a first fiber, and a second silicon lens configured to convert a second mode between a second waveguide and a second fiber, and a glass block coupled to the lens array and configured to provide an optical path for a first light beam corresponding to the first silicon lens and a second light beam corresponding to the second silicon lens.

Abstract: A multi-channel mode converter includes a lens array having a first lens and a second lens, a glass block coupled to the lens array, and a fiber assembly unit (FAU) array coupled to the glass block, the FAU array including a first fiber corresponding to the first lens, and a second fiber corresponding to the second lens. The FAU array provides for a corresponding number of fibers and lenses such that a specific single fiber corresponds to a specific single lens, there being a 1:1 relationship between fibers and lenses. A mode converter system comprises: a lens array comprising: a first silicon lens configured to convert a first mode between a first waveguide and a first fiber, and a second silicon lens configured to convert a second mode between a second waveguide and a second fiber, and a glass block coupled to the lens array and configured to provide an optical path for a first light beam corresponding to the first silicon lens and a second light beam corresponding to the second silicon lens.

Abstract: A gapless optical mode converter comprising a fiber holder configured to receive and hold an optical transmission line, a first glass block coupled via an optical adhesive at a first side to the fiber holder, a lens coupled via the optical adhesive at a first side to a second side of the first glass block, and a holder configured to hold the fiber holder, the first glass block, and the lens.

Abstract: An optical modulator for generating quadrature amplitude modulation (nQAM) and phase-shift keying (nPSK) signals with tunable modulation efficiency. The modulator includes a controlling circuit for adjusting the modulation efficiency or modulation depth of the modulator by controlling the direct current (DC) bias.

Abstract: An optical transceiver comprising an optical signal input, a first modulation section coupled to the optical signal input, a second modulation section coupled to the optical signal input and positioned in serial with the first modulation section, wherein the first modulation section comprises a first digital electrical signal input, a first digital driver coupled to the first digital electrical signal input, and a first modulator coupled to the first digital driver, and wherein the second modulation section comprises a second digital electrical signal input, a second digital driver coupled to the second digital electrical signal input, and a second modulator coupled to the second digital driver, and an optical signal output coupled to the first modulation section and the second modulation section.

Abstract: An apparatus comprises: a first input tap; a first optical modulator coupled to the first input tap; a first output tap coupled to the first optical modulator so that the first optical modulator is positioned between the first input tap and the first output tap; and a controller indirectly coupled to the first input tap and the first output tap.

Abstract: A method comprising coupling a circuit to an opto-electronic package via an anisotropic conductive film (ACF), wherein the opto-electronic package is configured to communicate electrical signals via the coupling at a maximum frequency of about 10 gigahertz (GHz) to about 40 GHz. An apparatus comprising, an opto-electronic package comprising a plurality of first electrodes, and a circuit comprising a plurality of second electrodes, wherein at least one of the first electrodes is coupled to at least one of the second electrodes via an ACF, and wherein the opto-electronic package is configured to communicate electrical signals via the coupling at a maximum frequency of about 10 GHz to about 40 GHz.

Abstract: An apparatus comprises: a first input tap; a first optical modulator coupled to the first input tap; a first output tap coupled to the first optical modulator so that the first optical modulator is positioned between the first input tap and the first output tap; and a controller indirectly coupled to the first input tap and the first output tap.

Abstract: A gapless optical mode converter comprising a fiber holder configured to receive and hold an optical transmission line, a first glass block coupled via an optical adhesive at a first side to the fiber holder, a lens coupled via the optical adhesive at a first side to a second side of the first glass block, and a holder configured to hold the fiber holder, the first glass block, and the lens.

Abstract: An optical modulator for generating quadrature amplitude modulation (nQAM) and phase-shift keying (nPSK) signals with tunable modulation efficiency. The modulator includes a controlling circuit for adjusting the modulation efficiency or modulation depth of the modulator by controlling the direct current (DC) bias.

Abstract: Embodiments of the invention provide regioselectively substituted carbohydrate and polysaccharide derivatives, such as cellulose esters, and methods for preparing them. Particular methods of the invention include deacylation of esters using tetrabutylammonium fluoride to obtain selective substitution at desired hydroxyl position(s) of the ester. Preferred is deacylation of an ester, which shows selectivity for removal of acyl groups from the ester of the secondary alcohols at C-2 and C-3, and which affords cellulose-6-O-esters with high regioselectivity by a simple one-step process employing no protective groups. Inventive regioselectively substituted cellulose esters can be prepared by such methods to obtain esters with the following anhydroglucose repeating units: wherein R1, R2, and R3 are each independently chosen from a hydrogen atom, and, whether substituted or unsubstituted, branched or unbranched, an alkanoyl group, an aroyl group, and a heteroaroyl group.

Abstract: An optical transceiver comprising an optical signal input, a first modulation section coupled to the optical signal input, a second modulation segment coupled to the optical signal input and positioned in serial with the first modulation section, wherein the first modulation section comprises a first digital electrical signal input, a first digital driver coupled to the first digital electrical signal input, and a first modulator coupled to the first digital driver, and wherein the second modulation section comprises a second digital electrical signal input, a second digital driver coupled to the second digital electrical signal input, and a second modulator coupled to the second digital driver, and an optical signal output coupled to the first modulation section and the second modulation section.

Abstract: An apparatus comprising a thick waveguide comprising a first adiabatic tapering from a first location to a second location, wherein the first adiabatic tapering is wider at the first location than at the second location, and a thin slab waveguide comprising a second adiabatic tapering from the first location to the second location, wherein the second adiabatic tapering is wider at the second location than at the first location, and a third adiabatic tapering from the second location to a third location, wherein the third adiabatic tapering is wider at the second location than at the third location, wherein at least a portion of the first adiabatic tapering is adjacent to the second adiabatic tapering, and wherein the first adiabatic tapering and the second adiabatic tapering are separated from each other by a constant gap.

Abstract: An optical transceiver comprising an optical signal input, a first modulation section coupled to the optical signal input, a second modulation section coupled to the optical signal input and positioned in serial with the first modulation section, wherein the first modulation section comprises a first digital electrical signal input, a first digital driver coupled to the first digital electrical signal input, and a first modulator coupled to the first digital driver, and wherein the second modulation section comprises a second digital electrical signal input, a second digital driver coupled to the second digital electrical signal input, and a second modulator coupled to the second digital driver, and an optical signal output coupled to the first modulation section and the second modulation section.

Abstract: An optical transceiver comprising an optical signal input, a first modulation section coupled to the optical signal input, a second modulation section coupled to the optical signal input and positioned in serial with the first modulation section, wherein the first modulation section comprises a first digital electrical signal input, a first digital driver coupled to the first digital electrical signal input, and a first modulator coupled to the first digital driver, and wherein the second modulation section comprises a second digital electrical signal input, a second digital driver coupled to the second digital electrical signal input, and a second modulator coupled to the second digital driver, and an optical signal output coupled to the first modulation section and the second modulation section.

Abstract: An apparatus comprising a thick waveguide comprising a first adiabatic tapering from a first location to a second location, wherein the first adiabatic tapering is wider at the first location than at the second location, and a thin slab waveguide comprising a second adiabatic tapering from the first location to the second location, wherein the second adiabatic tapering is wider at the second location than at the first location, and a third adiabatic tapering from the second location to a third location, wherein the third adiabatic tapering is wider at the second location than at the third location, wherein at least a portion of the first adiabatic tapering is adjacent to the second adiabatic tapering, and wherein the first adiabatic tapering and the second adiabatic tapering are separated from each other by a constant gap.

Abstract: An optical apparatus, comprising a polarization beam splitter (PBS) comprising a birefringent crystal having a front-end and a back-end, and an optical rotator positioned on the back-end of the birefringent crystal. Included is an optical apparatus comprising a PBS comprising a birefringent crystal and an optical rotator, wherein the PBS is configured to receive a multiplexed optical signal comprising a first polarized optical signal and a second polarized optical signal, wherein the second polarized optical signal is orthogonal to the first polarized optical signal, separate the first polarized optical signal from the second polarized optical signal using the birefringent crystal, and rotate the second polarized optical signal using the optical rotator such that the rotated second polarized optical signal is parallel to the first polarized optical signal. The PBS may further comprise only one lens, wherein the lens is positioned on the front-end of the birefringent crystal.

Abstract: An optical transceiver comprising an optical signal input, a first modulation section coupled to the optical signal input, a second modulation segment coupled to the optical signal input and positioned in serial with the first modulation section, wherein the first modulation section comprises a first digital electrical signal input, a first digital driver coupled to the first digital electrical signal input, and a first modulator coupled to the first digital driver, and wherein the second modulation section comprises a second digital electrical signal input, a second digital driver coupled to the second digital electrical signal input, and a second modulator coupled to the second digital driver, and an optical signal output coupled to the first modulation section and the second modulation section.

Abstract: Embodiments of the invention provide regioselectively substituted carbohydrate and polysaccharide derivatives, such as cellulose esters, and methods for preparing them. Particular methods of the invention include deacylation of esters using tetrabutylammonium fluoride to obtain selective substitution at desired hydroxyl position(s) of the ester. Preferred is deacylation of an ester, which shows selectivity for removal of acyl groups from the ester of the secondary alcohols at C-2 and C-3, and which affords cellulose-6-O-esters with high regioselectivity by a simple one-step process employing no protective groups. Inventive regioselectively substituted cellulose esters can be prepared by such methods to obtain esters with the following anhydroglucose repeating units: wherein R1, R2, and R3 are each independently chosen from a hydrogen atom, and, whether substituted or unsubstituted, branched or unbranched, an alkanoyl group, an aroyl group, and a heteroaroyl group.