US 12,468,184 B2
High performance optical modulators and drivers
Mian Zhang, Cambridge, MA (US); Christian Reimer, Wellesley, MA (US); and Prashanta Kharel, Cambridge, MA (US)
Assigned to HyperLight Corporation, Cambridge, MA (US)
Filed by HyperLight Corporation, Cambridge, MA (US)
Filed on Jun. 1, 2021, as Appl. No. 17/335,915.
Claims priority of provisional application 63/033,666, filed on Jun. 2, 2020.
Prior Publication US 2021/0373364 A1, Dec. 2, 2021
Int. Cl. G02F 1/035 (2006.01); G02F 1/225 (2006.01); G02B 6/12 (2006.01)
CPC G02F 1/0356 (2013.01) [G02F 1/2255 (2013.01); G02B 2006/12142 (2013.01); G02F 2201/127 (2013.01); G02F 2202/20 (2013.01)] 28 Claims
OG exemplary drawing
 
1. An interface to an optical modulator, comprising:
a first differential line pair having a first differential line pair negative line and a first differential line pair positive line arranged on opposing sides of a first waveguide, wherein the first differential line pair negative line is arranged on a distal side of the first waveguide relative to a second waveguide and the first differential line pair positive line is arranged on a proximal side of the first waveguide relative to the second waveguide, wherein each of the first waveguide and the second waveguide is formed from a thin film of at least one of lithium niobate or lithium tantalate, the thin film having a thickness of not more than two micrometers; and
a second differential line pair having a second differential line pair negative line and a second differential line pair positive line arranged on opposing sides of the second waveguide, wherein the second differential line pair negative line is arranged on a distal side of the second waveguide relative to the first waveguide and the second differential line pair positive line is arranged on a proximal side of the second waveguide relative to the first waveguide;
wherein the first waveguide and the first differential line pair in combination with the second waveguide and the second differential line pair provide optical modulation for a frequency bandwidth of 50-100 GHZ;
a first line coupled to the first differential line pair negative line and to the second differential line pair negative line, the first line being connectable to an output of a differential driver;
a second line coupled to the first differential line pair positive line and to the second differential line pair positive line, the second line being connectable to another output of the differential driver; and
wherein the first differential line pair, the second differential line pair, the first waveguide and the second waveguide are on a substrate structure including a substrate and an underlayer on the substrate, the substrate having a substrate microwave dielectric constant, the underlayer having an underlayer dielectric constant less than the substrate microwave dielectric constant such that the substate structure has a total microwave dielectric constant less than eleven in a region of a microwave mode for each line of the first differential line pair and the second differential line pair;
wherein the first differential line pair negative line and the second differential line pair negative line and the first differential line pair positive line and the second differential line pair positive line have a first impedance difference; and
wherein the first line and the second line have a second impedance difference configured to compensate for the first impedance difference.