A broadband external cavity tunable InAs/GaAs quantum dot laser by utilizing only the ground state emission

A broadband external cavity tunable laser is realized by using a broad-emitting spectral InAs/GaAs quantum dot （QD） gain device. A tuning range of 69 nm with a central wavelength of 1056 nm, is achieved at a bias of 1.25 kA/cm^2only by utilizing the light emission from the ground state of QDs. This large tunable range only covers the QD ground-state emission and is related to the inhomogeneous size distribution of QDs. No excited state contributes to the tuning bandwidth. The application of the QD gain device to the external cavity tunable laser shows its immense potential in broadening the tuning bandwidth. By the external cavity feedback, the threshold current densitycan be reduced remarkably compared with the free-running QD gain device.

Broadband tunable external cavity laser using a bent-waveguide quantum-dot superluminescent diode as gain device

A broadband tunable grating-coupled external cavity laser is realized by employing a self-assembled InAs/GaAs quantum-dot （QD） superluminescent diode （SLD） as the gain device. The SLD device is processed with a bent-waveguide structure and facet antireflection （AR） coating. Tuning bandwidths of 106 nm and 117 nm are achieved under a-A and 3.5-A injection currents, respectively. The large tuning range originates essentially from the broad gain spectrum of self-assembled QDs. The bent waveguide structure combined with the facet AR coating plays a role in suppressing the inner-cavity lasing under a large injection current.

High-Q whispering gallery modes in a polymer microresonator with broad strain tuning

We have reported the high-Q whispering gallery modes(WGMs) in a polydimethylsiloxane(PDMS) optical microresonators with broad tuning range. The PDMS microresonators are fabricated at the center of two collimating fiber tips, which can be controlled by the piezoelectric stage. Through stretching the fiber stem, the tuning range of WGMs are demonstrated more than 50 nm.Further investigations demonstrated that the WGM shift has a high force sensitivity(～ 19.7 pm/μN) of the gravitation when the microcavity is stretched by a weight. The theoretical analysis reveals that the high force sensitivity of polymer microresonator can be used for the weak force or height measurement.

Laser performance of a broadband wavelength tunable Yb:germanophosphate glass with direct diode pumping

The laser performance of a new Yb：germanophosphate（Yb：GP） glass is investigated. A maximum output power of 826 m W at 1063 nm is achieved with direct diode pumping at 976 nm. The wavelength is tuned from 1034.47 to 1070.83 nm, corresponding to a tuning range of 36.36 nm. Thermal lens effects are investigated to optimize the optical cavity.

Soliton formation with controllable frequency line spacing using dual pumps in a microresonator

Temporal cavity solitons（CSs） have excellent properties that can sustain their shape in a temporal profile and with a broadband, smooth-frequency spectrum. We propose a method for controllable frequency line spacing soliton formation in a microresonator using two continuous-wave（CW） pumps with multi-free-spectral-range（FSR） spacing. The method we propose has better control over the amount and location of the solitons traveling in the cavity compared to the tuning pump method. We also find that by introducing a second pump with frequency N FSR from the first pump, solitons with N FSR comb spacing can be generated.