Rare-Earth-Ion-Doped Channel Waveguide Lasers on Silicon

Abstract

This paper reviews the recent developments in rareearth-ion-doped planar and channel waveguide lasers. Optical gain in rare-earth-ion-doped waveguides has been increased by two orders of magnitude to ~1000 dB/cm and waveguide lasers with extremely high slope efficiencies and output powers exceeding the Watt level have been demonstrated. Of particular interest in integrated optics is the recent integration of rareearth-ion-doped channel waveguide lasers in amorphous materials directly deposited on a silicon substrate. Remarkable performance with respect to slope efficiency, output power, and laser linewidth has been achieved.

High-gain waveguide amplifiers in Si3N4 technology via double-layer monolithic integration

“…Recently, monolithic integration of rare-earth-ion-doped (RE 3 ) aluminum oxide (Al 2 O 3 ) and Si 3 N 4 was demonstrated [18][19][20][21][22][23], showing potential for high-performance scalable light sources on the Si 3 N 4 platform. Compared to III-V semiconductors [24], RE 3 -ion-doped materials have a longer excitedstate lifetime (0.1-10 ms) [25] and less refractive index change (∼10 −6 ) [26] induced by the excitation of the doped ions, properties that are beneficial for thermally and spatially stable gain [27]. The high rare-earth ion dopant concentration achievable in crystalline host materials has allowed the demonstration of very high gain per unit length in an Yb 3 -doped KYWO 4 2 waveguide (∼935 dB∕cm at 980 nm) [28] and in an Er 3 -doped chloride silicate nanowire (∼100 dB∕cm at 1530 nm).…”

Room-temperature near-infrared up-conversion lasing in single-crystal Er-Y chloride silicate nanowires

“…For example, by embedding the EYCS nanowires into high-index silicon, the radiative efficiency of Er 3+ in the double slot waveguides will be significantly improved 25 26 27 . Building an external cavity can provide light feedback, which will also help to enhance the proportion of the remaining light in the nanowires 27 28 29 30 31 32 . What’s more, in view of the high-intensity radiation over a wide wavelength range, there is a tremendous opportunity to achieve an effective and cheap monolithic white laser by adopting three parallel-placed Er-Y silicate nanowires if an additional grating or photonic crystal is etched and integrated into the surface of the nanowires to help separate light from blue, yellow and red band, respectively 33 34 35 .…”

Rare-earth ion doped Al2O3 for active integrated photonics

“…Al 2 O 3 can be deposited using a variety of methods including synthesis by the solgel method [52][53][54][55][56][57], chemical vapor deposition (CVD) [58,59], pulsed laser deposition (PLD) [60][61][62][63][64][65], atomic layer deposition (ALD) [11,27,[66][67][68][69][70][71][72][73] and reactive sputtering [3][4][5][6][7][8][9][10][12][13][14][15][16][20][21][22]26,[29][30][31][32][33][34][35][36][37][38]…”

“…Rare-earth ion doped Al 2 O 3 has been used in the last few decades for the realization of on-chip amplifiers [7,9,15,20,[23][24][25][26][27][28]46] and lasers [8,10,12,15,18,19,21,22,[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] that exhibited ultra-narrow linewidths down to 1.7 kHz [31], broad tunability [39] and relatively high output power [41,45]. Its monolithic integration with different passive photonic integration platforms, including Si 3 N 4 [8,10,[12][13][14]27,[33][34][35]...…”