An apparatus including a single-chip integrated-optics-based optical spectrometer, wherein the spectrometer comprises: a coupler (102, 1006) for distributing an input light signal (110, 1010) into a first light signal (110A, 1010A) on a sample bus (104A, 1008A) and a second light signal (110B, 1010B) on a reference bus (104B, 1008B); a plurality of nested interferometers (MZI-1 through MZI-N), each interferometer of the plurality thereof being a Mach-Zehnder interferometer (MZI-i) that includes: (i) a sample path operative for conveying the first light signal (110A, 1010A), the sample path having a first length and including a portion of the sample bus (104A, 1008A); (ii) a reference path operative for conveying the second light signal (110B, 1010B), the reference path having a second length and including a portion of the reference bus (104B, 1008B); (iii) an interference section (106-1 through 106-N) that includes a beam combiner (406-1 through 406-N) that is operative for combining the first light signal (110A, 1010A) and second light signal (110B, 1010B) into an interference signal (118-i, 1022-i); and (iv) a photodetector (120-1 through 120-N) for providing an output signal (122-i) that is based on the optical power of the interference signal (118-i, 1022-i); wherein each interferometer (MZI-i) of the plurality thereof is characterized by a different path-length difference between its respective first length and second length. a coupler (102, 1006) for distributing an input light signal (110, 1010) into a first light signal (110A, 1010A) on a sample bus (104A, 1008A) and a second light signal (110B, 1010B) on a reference bus (104B, 1008B); a plurality of nested interferometers (MZI-1 through MZI-N), each interferometer of the plurality thereof being a Mach-Zehnder interferometer (MZI-i) that includes: (i) a sample path operative for conveying the first light signal (110A, 1010A), the sample path having a first length and including a portion of the sample bus (104A, 1008A); (ii) a reference path operative for conveying the second light signal (110B, 1010B), the reference path having a second length and including a portion of the reference bus (104B, 1008B); (iii) an interference section (106-1 through 106-N) that includes a beam combiner (406-1 through 406-N) that is operative for combining the first light signal (110A, 1010A) and second light signal (110B, 1010B) into an interference signal (118-i, 1022-i); and (iv) a photodetector (120-1 through 120-N) for providing an output signal (122-i) that is based on the optical power of the interference signal (118-i, 1022-i); (i) a sample path operative for conveying the first light signal (110A, 1010A), the sample path having a first length and including a portion of the sample bus (104A, 1008A); (ii) a reference path operative for conveying the second light signal (110B, 1010B), the reference path having a second length and including a portion of the reference bus (104B, 1008B); (iii) an interference section (106-1 through 106-N) that includes a beam combiner (406-1 through 406-N) that is operative for combining the first light signal (110A, 1010A) and second light signal (110B, 1010B) into an interference signal (118-i, 1022-i); and (iv) a photodetector (120-1 through 120-N) for providing an output signal (122-i) that is based on the optical power of the interference signal (118-i, 1022-i); wherein each interferometer (MZI-i) of the plurality thereof is characterized by a different path-length difference between its respective first length and second length.