Direct Determination of Optical Gain in Semiconductor Crystals

Shaklee, K. L.; Leheny, R. F.

doi:10.1063/1.1653501

Cited by 445 publications

(248 citation statements)

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“…If the modal gain exceeds the total losses, the spontaneous emission is amplified along the waveguide. To measure the net gain, including propagation losses due to non-resonant residual absorption as well as disorder-induced scattering, we use a standard method originally introduced in the seminal work of Shaklee et al 33 The output intensity may be written as…”

Section: Resultsmentioning

confidence: 99%

Slow-light-enhanced gain in active photonic crystal waveguides

Lunnemann

Chen

et al. 2014

Nat Commun

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Passive photonic crystals have been shown to exhibit a multitude of interesting phenomena, including slow-light propagation in line-defect waveguides. It was suggested that by incorporating an active material in the waveguide, slow light could be used to enhance the effective gain of the material, which would have interesting application prospects, for example enabling ultra-compact optical amplifiers for integration in photonic chips. Here we experimentally investigate the gain of a photonic crystal membrane structure with embedded quantum wells. We find that by solely changing the photonic crystal structural parameters, the maximum value of the gain coefficient can be increased compared with a ridge waveguide structure and at the same time the spectral position of the peak gain be controlled. The experimental results are in qualitative agreement with theory and show that gain values similar to those realized in state-of-the-art semiconductor optical amplifiers should be attainable in compact photonic integrated amplifiers.

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Section: Resultsmentioning

confidence: 99%

Slow-light-enhanced gain in active photonic crystal waveguides

Lunnemann

Chen

et al. 2014

Nat Commun

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“…However, for the optical gain measurements, the ASE was detected from the in-plane direction and the gain coefficients of the ASE were obtained by using the VSL excitation method. 15,16 In the measurements, the stripe length of a rectangular excitation beam focused through cylindrical lenses and an aperture was varied from 0 to 0.15 mm, and the emitted light passing through the stripe region was detected. Figure 1 shows PL spectra of the BP1T crystal under the weak excitation by a He-Cd laser as a function of temperature.…”

Section: Methodsmentioning

confidence: 99%

Origin of the amplified spontaneous emission from thiophene/phenylene co-oligomer single crystals: Towards co-oligomer lasers

Bando

Nakamura

Masumoto

et al. 2006

Journal of Applied Physics

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Photoluminescence ͑PL͒ and optical gain measurements have been performed for single crystals of thiophene/phenylene co-oligomer at room and low temperatures. Broad PL bands are transformed to be an ensemble of several spectrally narrower vibronic peaks with decreasing temperature. Very sharp lines as narrow as ϳ3 meV are observed at 10 K under weak excitation. Intensities of sharp emission lines superlinearly increased at 10 K under intense excitation, showing the amplified spontaneous emission ͑ASE͒. The ASE bands were clearly identified to the sidebands of B 1 and A 1 + B 1 vibronic modes. The ASE is also observed at room temperature under the intense excitation. Spectroscopic investigation at varied temperatures enabled us to identify the origin of the ASE band to the vibronic sidebands of the electronic transition of the thiophene/phenylene co-oligomer crystals. In addition, highly polarized optical gains ϳ50 cm −1 were obtained for the two ASE bands at room temperature.

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“…A relatively straightforward technique to determine the steady-state gain spectrum for an optically active medium is the variable stripe length method, originally introduced in Ref. 5. Here, the emission from a homogeneously illuminated stripe of varying length is collected out of a cleaved edge as a function of the stripe length.…”

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confidence: 99%