Abstract: A VCSEL transmitter includes a first VCSEL terminal disposed on a substrate and a second VCSEL terminal adjacent thereto. The transmitter also includes a first diffraction element within a first optical path of the first VCSEL terminal which receives and changes a first direction of a first light transmission having a low-order Laguerre Gaussian mode emitted from the first VCSEL terminal. The transmitter further includes a second diffraction element within a second optical path of the second VCSEL terminal which receives the second light transmission and converts the received light into a high-order Laguerre Gaussian mode. The transmitter also includes a mode combiner to direct the first light transmission into a lens which directs the light into a multi-mode optical fiber.

Abstract: A VCSEL transmitter includes aa first VCSEL terminal disposed on a substrate and a second VCSEL terminal adjacent thereto. The transmitter also includes a first diffraction element within a first optical path of the first VCSEL terminal which receives and changes a first direction of a first light transmission having a low-order Laguerre Gaussian mode emitted from the first VCSEL terminal. The transmitter further includes a second diffraction element within a second optical path of the second VCSEL terminal which receives the second light transmission and converts the received light into a high-order Laguerre Gaussian mode. The transmitter also includes a mode combiner to direct the first light transmission into a lens which directs the light into a multi-mode optical fiber.

Abstract: A controllable optical ring resonator, a photonic system and a method of controlling an optical ring resonator employ control electrodes periodically spaced apart along a closed loop optical path of an optical waveguide. The controllable optical ring resonator includes the optical waveguide and a plurality of the periodically spaced control electrodes. The photonic system includes an input optical waveguide segment and the controllable optical ring resonator adjacent and optically coupled to the segment. The method includes providing the plurality of periodically spaced control electrodes, providing an optical signal within the optical path, and addressing one or more of the control electrodes to interact with the optical signal within the optical path.

Abstract: A hybrid guided-mode resonance (GMR) grating, an optical filter and a method of optical filtering employ distributed Bragg reflection. The hybrid GMR grating includes a waveguide layer that supports a GMR having a GMR resonant frequency. The hybrid GMR grating further includes a diffraction grating that couples a portion of a signal incident on the hybrid GMR grating into the waveguide layer; and a distributed Bragg reflector (DBR) that reflects another portion of the incident signal. The coupled portion of the incident signal has a frequency corresponding to the GMR resonant frequency. The reflected portion has a frequency away from the GMR resonant frequency. The optical filter includes the hybrid GMR grating and a coupler. The method includes coupling an optical signal into the hybrid GMR grating and further coupling a reflected signal out of the hybrid GMR grating.

Abstract: A hybrid guided-mode resonance (GMR) grating, an optical filter and a method of optical filtering employ distributed Bragg reflection. The hybrid GMR grating includes a waveguide layer that supports a GMR having a GMR resonant frequency. The hybrid GMR grating further includes a diffraction grating that couples a portion of a signal incident on the hybrid GMR grating into the waveguide layer; and a distributed Bragg reflector (DBR) that reflects another portion of the incident signal. The coupled portion of the incident signal has a frequency corresponding to the GMR resonant frequency. The reflected portion has a frequency away from the GMR resonant frequency. The optical filter includes the hybrid GMR grating and a coupler. The method includes coupling an optical signal into the hybrid GMR grating and further coupling a reflected signal out of the hybrid GMR grating.

Abstract: A nanowire-based photodiode and an interdigital p-i-n photodiode use an i-type semiconductor nanowire in an i-region of the photodiode. The nanowire-based photodiode includes a first sidewall of a first semiconductor doped with a p-type dopant, a second sidewall of the first semiconductor doped with an n-type dopant, and an intrinsic semiconductor nanowire that spans a trench between the first and second sidewalls. The trench is wider at a top than at a bottom adjacent to a substrate. The first semiconductor of one or both of the first sidewall and the second sidewall is single crystalline and together the first sidewall, the nanowire and the second sidewall form a p-i-n semiconductor junction of the photodiode.

Abstract: A controllable optical ring resonator, a photonic system and a method of controlling an optical ring resonator employ control electrodes periodically spaced apart along a closed loop optical path of an optical waveguide. The controllable optical ring resonator includes the optical waveguide and a plurality of the periodically spaced control electrodes. The photonic system includes an input optical waveguide segment and the controllable optical ring resonator adjacent and optically coupled to the segment. The method includes providing the plurality of periodically spaced control electrodes, providing an optical signal within the optical path, and addressing one or more of the control electrodes to interact with the optical signal within the optical path.

Abstract: A modulator having a waveguide and a microdisk resonator is disclosed. The waveguide has an input port for receiving a light signal of wavelength ? and an output port for transmitting modulated light. The microdisk resonator has a resonance at ? and is coupled to the waveguide between the input and output ports such that at least 10 percent of the light traveling in the waveguide is coupled to the microdisk resonator. The microdisk resonator further includes a material having a first state and a second state, the material absorbing more of the light in the first state than in the second state. The first and second states are selectable by a signal that is applied to the microdisk resonator. In one embodiment, the waveguide and the microdisk resonator occupy different portions of a sheet of material having the various layers used to construct the resonator.

Abstract: A laser, a p-spacer, an n-spacer, and an active region is disclosed. The p-spacer has a p-doped region and an undoped region, and the n-spacer has an n-doped region and an undoped region. The active region is located between the undoped regions of the p-spacer and the n-spacer. The active region generates light of wavelength &lgr; through the recombination of holes and electrons. The undoped region of the p-spacer has a thickness that is different from that of the undoped region of the n-spacer. In one embodiment, the p-spacer has a thickness greater than the n-spacer. If the laser is a VCSEL, the p-spacer and the n-spacer form an optical cavity having a thickness Lc=(n+1)&lgr;/2, n is an integer greater than 2. In another embodiment, the cavity has a standing electromagnetic wave and wherein the active layer is located at a maximum of the standing electromagnetic wave.

Abstract: A light source that includes first and second waveguides and a passive resonator for coupling light between the waveguides. The waveguides include a gain region for amplifying light of a desired wavelength, a transparent region, and an absorption region. The passive resonator couples light of the desired wavelength between the first and second transparent regions of the first and second waveguides and has a resonance at that wavelength. The resonator is preferably a microdisk resonator. The index of refraction of the microdisk resonator can be altered to select the desired wavelength. A second microdisk resonator having a different radius may be incorporated to increase the tuning range of the light source. The resonator is preferably constructed over the waveguides with an air gap between the resonator and the substrate in which the waveguides are constructed.

Abstract: A VCSEL 101 comprising an optical cavity having an optical loss and a loss-determining element 117 coupled to the optical cavity. The loss-determining element 117 progressively increases the optical loss of the optical cavity with increasing lateral distance from the optical axis 105. The optical cavity includes a first mirror region 111, a second mirror region 107, a plane light-generating region 125 sandwiched between the first mirror region 111 and the second mirror region 107, perpendicular to the optical axis 105, and an element 113 that defines the lateral extent of the optical cavity in the plane of the light-generating region 125. The first mirror region 111 and the second mirror region 107 are both conductive and have opposite conductivity modes.

Abstract: A contact structure for a vertical cavity surface emitting laser is described. The contact structure comprises a surface metal contact, a degeneratively doped layer of low bandgap material less than 200 .ANG. thick, and a plurality of current spreading layers. The contact structure provides a low ohmic path between the metal contact and the active region of the vertical cavity surface emitting laser.

Abstract: The present invention provides a low noise multimode VCSEL that can be used to transmit data reliably on multimode optical media at data rates up to and exceeding 1 gigabit per second with bit error rates less than 1.times.10.sup.-9 errors/bit. In contrast to conventional multimode lasers where optimal mirror reflectivity is designed for maximum power output, in the present invention mirror reflectivity is increased to a point where the output power is less than half the maximum output power. Preferably, the reflectivity of the first and second mirror regions of the multimode laser is high, typically greater than 99.5%.