A superconducting chip comprising: a ground plane; a coiled coupled-line hybrid coupler, the coupler comprising: a first port configured to receive an input signal from a microwave object; second and third ports (112, 114) amongst which the power of the input signal is split with about 90° phase separation; a primary transmission line galvanically connecting the first port and one of the two other ports (112, 114), the primary transmission line being coiled in at least two biplanar coils (402, 404) in series with each other; and a coiled secondary transmission line galvanically connected with the other of the two other ports (112, 114) and not galvanically connected with the primary transmission line, the secondary transmission line coiled in the at least two biplanar coils (402, 404) and about uniformly spaced by a coupling distance from the primary transmission line in at least one planar dimension over a coupling length that includes the at least two biplanar coils (402, 404), the secondary transmission line thereby being capacitively and inductively coupled to the primary transmission line; wherein, over at least a portion of the coupling length in each of the at least two biplanar coils (402, 404), one of the primary and secondary transmission lines (116, 118) is surrounded by, and is substantially the coupling distance from, the other of the transmission lines (116, 118) on at least three sides, as viewed from a transverse-plane cross-section of the one transmission line, wherein the at least two biplanar coils (402, 404) are between about one hundred nanometers and about five hundred nanometers separated from the ground plane, as viewed from the transverse-plane cross-section, and wherein the coupling distance is selected such that an odd-mode impedance of the coupler is between about fifteen ohms and about twenty-five ohms, and an even-mode impedance between about one hundred ohms and about one hundred forty ohms. a ground plane; a coiled coupled-line hybrid coupler, the coupler comprising: a first port configured to receive an input signal from a microwave object; second and third ports (112, 114) amongst which the power of the input signal is split with about 90° phase separation; a primary transmission line galvanically connecting the first port and one of the two other ports (112, 114), the primary transmission line being coiled in at least two biplanar coils (402, 404) in series with each other; and a coiled secondary transmission line galvanically connected with the other of the two other ports (112, 114) and not galvanically connected with the primary transmission line, the secondary transmission line coiled in the at least two biplanar coils (402, 404) and about uniformly spaced by a coupling distance from the primary transmission line in at least one planar dimension over a coupling length that includes the at least two biplanar coils (402, 404), the secondary transmission line thereby being capacitively and inductively coupled to the primary transmission line; a first port configured to receive an input signal from a microwave object; second and third ports (112, 114) amongst which the power of the input signal is split with about 90° phase separation; a primary transmission line galvanically connecting the first port and one of the two other ports (112, 114), the primary transmission line being coiled in at least two biplanar coils (402, 404) in series with each other; and a coiled secondary transmission line galvanically connected with the other of the two other ports (112, 114) and not galvanically connected with the primary transmission line, the secondary transmission line coiled in the at least two biplanar coils (402, 404) and about uniformly spaced by a coupling distance from the primary transmission line in at least one planar dimension over a coupling length that includes the at least two biplanar coils (402, 404), the secondary transmission line thereby being capacitively and inductively coupled to the primary transmission line; wherein, over at least a portion of the coupling length in each of the at least two biplanar coils (402, 404), one of the primary and secondary transmission lines (116, 118) is surrounded by, and is substantially the coupling distance from, the other of the transmission lines (116, 118) on at least three sides, as viewed from a transverse-plane cross-section of the one transmission line, wherein the at least two biplanar coils (402, 404) are between about one hundred nanometers and about five hundred nanometers separated from the ground plane, as viewed from the transverse-plane cross-section, and wherein the coupling distance is selected such that an odd-mode impedance of the coupler is between about fifteen ohms and about twenty-five ohms, and an even-mode impedance between about one hundred ohms and about one hundred forty ohms.