Waferscale nanophotonic circuits made from diamond-on-insulator substrates

Abstract

Wide bandgap dielectrics are attractive materials for the fabrication of photonic devices because they allow broadband optical operation and do not suffer from free-carrier absorption. Here we show that polycrystalline diamond thin films deposited by chemical vapor deposition provide a promising platform for the realization of large scale integrated photonic circuits. We present a full suite of photonic components required for the investigation of on-chip devices, including input grating couplers, millimeter long nanophotonic waveguides and microcavities. In microring resonators we measure loaded optical quality factors up to 11,000. Corresponding propagation loss of 5dB/mm is also confirmed by measuring transmission through long waveguides.

High quality-factor optical nanocavities in bulk single-crystal diamond

“…From measured Q-factors, an upper limit on the diamond waveguide transmission loss (a) is estimated to be B1.5 dB cm À 1 for both guided modes via the relationship 25 : a % 2pn g Q i l = , where n g is the mode group index and l is the resonant wavelength. While this loss value is roughly five times greater than that recently reported for single-crystal diamond waveguides fabricated via the membrane-thinning approach 18 , it is also an order of magnitude smaller than losses of polycrystalline diamond ring resonators 26 .…”

Diamond Nanophotonics

“…In contrast, Ref. [111] demonstrated diamond microring resonators (Q=11000) on the SiO 2 substrate coupled to mm long waveguides with propagation losses of 5 dB/mm. It should be noted, that these circuits are optimal for the near infrared region (~ 1.5 µm) where the absorption and scattering from the grain boundaries is minimal.…”

“…Using this technique, 1-2 nm thick layers containing NV centers have been demonstrated, however, the lateral placement can´t be controlled and the efficiency of NV creation is low [35] . Very recently, NV centers in high-purity (111) oriented CVD diamonds have been shown to align almost perfectly along the [111] growth direction instead of aligning along all 4 equivalent <111> directions [36,37] . Thus, optimal alignment of the NV`s emission dipoles with respect to photonic structures is feasible in contrast to previous work using (100) oriented diamonds [38] .…”

Synthesis of luminescent europium defects in diamond

“…Currently, diamond is one of the pre-eminent platforms for high resolution magnetometry and quantum information processing, owing to the nitrogen vacancy (NV) defect [12][13][14][15] . Diamond possesses a very large band gap (5.5 eV) that can accommodate a variety of optically active defects.…”