Programmable integrated photonic circuits offer a compact, low-power and ver-satile method for the control of light. Unlike conventional electronics, photonictechnologies can operate at higher speeds and have increased bandwidth as mul-tiple wavelengths of light can be sent through a single optical fiber allowing forunparalleled transfer of information. By combining these impressive attributeswith single photons, the advantages of such circuits can be greatly enhancedas this allows for the possibility of secure quantum communication and thepossibility to use these circuits as a testbed for fundamental quantum physicsexperiments.The photonic circuit investigated in this thesis was a universal multiport inter-ferometer consisting of eight modes was calibrated for use in single photon exper-iments. This circuit used the rectangular architecture developed by Clementswhich consists of a mesh of MZIs and phase shifters in a silicon-on-insulatorplatform. The structure was designed using Nazca, with the waveguides andMMI couplers fabricated by SiPhotonIC technologies and the photonic packag-ing completed by Quix.Entangled photon pairs at 1550 nm generated by a Type- II periodically poledpotassium potassium titanyl phosphate crystal were used as the single photonsource in an experiment to emulate coherent perfect absorption. Given thatthe primary attraction of such an interferometer is the implementation of anyunitary operator, demonstrating an emulation of coherent absorption allows forthe possibility of implementing non-unitary matrices on such an interferome-ter through ancilla modes. The experiment modelled this absorption throughcoherent loss to an ancilla mode, tuning the absorption value by utilising thephase shifters to re-route the light while the input phase of the circuit was beingswept.This thesis opens up the door to further experiments involving loss and gainusing single photons by being able to tune their quantum interference. Modellingquantum phenomena has been a challenge for classical computers since theadvent of quantum mechanics due to the inherent differences between classicaland quantum computing and the inability to be able to accurately represent thequirks of quantum physics such as entanglement and superposition Thus, thedevelopment of these integrated quantum photonic circuits can directly lead tothe development of sophisticated, programmable quantum gates as well as theeventual execution of quantum information processing and simulation protocols.

Programmerbara integrerade fotoniska kretsar erbjuder en kompakt, str¨omsn˚aloch m˚angsidig metod f¨or att kontrollera ljus. Till skillnad fr˚an konventionellelektronik kan fotoniska teknologier arbeta i h¨ogre hastigheter och med ¨okadbandbredd eftersom flera v˚agl¨angder av ljus kan s¨andas genom en enda op-tisk fiber, vilket m¨ojligg¨or en o¨overtr¨affad informations¨overf¨oring. Genom attkombinera dessa imponerande egenskaper med enskilda fotoner kan f¨ordelarnamed s˚adana kretsar f¨orb¨attras avsev¨art, d˚a detta m¨ojligg¨or s¨aker kvantkommu-nikation samt anv¨andning av dessa kretsar som testb¨addar f¨or fundamentalaexperiment inom kvantfysik.Den fotoniska krets som unders¨oktes i detta examensarbete var en universellmultiport-interferometer best˚aende av˚atta l¨agen, som kalibrerades f¨or anv¨andningi experiment med enskilda fotoner. Denna krets anv¨ande den rektangul¨araarkitektur som utvecklats av Clements f¨or att f¨orb¨attra noggrannheten hos deunit¨ara operatorer som genereras med n¨atet av MZI er och fasv¨axlare. Struk-turen designades med hj¨alp av Nazca, d¨ar v˚agledare och MMI-kopplare tillverkadesav SiPhotonIC Technologies och den fotoniska paketeringen slutf¨ordes av Quix.Str¨ommodulatorer fr˚an f¨oretaget Quix anv¨andes f¨or att m¨ojligg¨ora exakt kon-troll av de termo-optiska fasv¨axlarna i kretsen.Entanglade fotonpar vid 1550 nm, genererade av en typ-II periodiskt polad kali-umtitanylfosfatkristall (KTP), anv¨andes som enskilda fotoner i ett experimentf¨or att efterlikna koherent perfekt absorption. Eftersom den fr¨amsta styrkan hosen s˚adan interferometer ¨ar m¨ojligheten att implementera godtyckliga unit¨ara op-eratorer, visar demonstrationen av en emulering av koherent absorption att det¨ar m¨ojligt att implementera icke-unit¨ara matriser p˚a en s˚adan interferometergenom anv¨andning av ancillal¨agen. Experimentet modellerade denna absorp-tion genom koherent f¨orlust till detta ancillal¨age, d¨ar absorptionsv¨ardet juster-ades genom att utnyttja fasv¨axlarna f¨or att omdirigera ljuset, samtidigt soming˚angsfasen i kretsen sveptes.Detta examensarbete ¨oppnar upp f¨or vidare experiment som involverar f¨orlustoch f¨orst¨arkning med enskilda fotoner genom att m¨ojligg¨ora justering av kvantin-terferens. Att modellera kvantfenomen har l¨ange varit en utmaning f¨or klassiskadatorer sedan kvantmekanikens uppkomst, p˚a grund av de inneboende skill-naderna mellan klassisk och kvantdatorer samt sv˚arigheten att exakt represen-tera kvantfysikens egenheter s˚asom sammanfl¨atning och superposition. D¨arf¨orkan utvecklingen av dessa integrerade kvantfotoniska kretsar direkt leda tillutvecklingen av sofistikerade, programmerbara kvantgrindar samt till slutlig im-plementering av kvantinformationsbearbetning och simuleringsprotokoll.