Process margin relaxation

A photonic element, comprising:

• an optical switch including a first splitter arm and a second splitter arm;
• a first optical device including a first input arm, a first output arm, and a second output arm, wherein the first input arm is connected to the first splitter arm, and wherein the first optical device satisfies a first fabrication tolerance range, wherein the first fabrication tolerance range includes a first upper range value and a first lower range value;
• a second optical device including a second input arm in communication with the second splitter arm, a third output arm, and a fourth output arm, wherein the second input arm is connected to the second splitter arm, wherein the second optical device satisfies a second fabrication tolerance range, wherein the second fabrication tolerance range includes (i) a second upper range value lower than the first lower range value and (ii) a second lower range value, and wherein the second fabrication tolerance range is different from the first fabrication tolerance range;
• a third optical device including a third input arm, a fifth output arm, and a sixth output arm, wherein the third input arm is connected to the first output arm, and wherein the third optical device satisfies the first fabrication tolerance range;
• a fourth optical device including a fourth input arm, a seventh output arm, and an eighth output arm, wherein the fourth input arm is connected to the third output arm, and wherein the fourth optical device satisfies the second fabrication tolerance range;
• a first optical combiner connected to the second output arm and the fourth output arm;
• a second optical combiner connected to the sixth output arm and the eighth output arm;
• and
• a third optical combiner connected to the fifth output arm and the seventh output arm;
• wherein the first optical device and the second optical device are respectively configured to output first optical signals in a first wavelength range via the first output arm and the third output arm and output second optical signals in a second wavelength range via the second output arm and the fourth output arm;
• and
• wherein the third optical device and the fourth optical device are respectively configured to output third optical signals in a third wavelength range via the fifth output arm and the seventh output arm and output fourth optical signals in a fourth wavelength range via the sixth output arm and the eighth output arm.

A method, comprising:

• fabricating a first optical device in a first substrate to satisfy a first fabrication tolerance range and comprising a first upper range value and a first lower range value;
• fabricating a second optical device in the first substrate to satisfy a second fabrication tolerance range comprising (i) a second upper range value lower than the first lower range value and (ii) a second lower range value;
• fabricating a first optical switch in the first substrate connected to an input and configured to output an optical signal received from the input to one of the first optical device and the second optical device;
• and
• fabricating a first optical combiner in the first substrate configured to combine outputs from the first optical device and the second optical device.