Micro-module with micro-lens
View Patent ↗Optical micro-modules include an integrated lens holder and microlens for passive coupling of optical signals into an optical fiber. The microlens includes a mounting surface and a curved section having an optical axis. The microlens curved section may be an aspheric silicon lens. The microlens mounting surface is attached to the lens holder mounting surface such that the microlens optical axis is centered with the optical fiber and aligned at a desired focal length from the optical fiber. The lens holder may, for example, be either in mechanical communication with a cable receptacle or be attached to a submount that has a silicon v-groove thereon for receiving an optical fiber. The optical micro-module may be part of other optical devices, for example a transmitter optical sub-assembly or a receiver optical sub-assembly.
1. A transmitter optical micro-module comprising:
a transmitter sub-module comprising:
a light emitter mounted upon a silicon substrate;
a lens holder mounted upon the silicon substrate adjacent the light emitter, the lens holder having a mounting surface;
a lens attached to the mounting surface of the lens holder at a desired focal distance from the light emitter for receiving an emitted optical signal from the light emitter and collimating the optical signal; and
a back monitor positioned adjacent a back facet of the light emitter for monitoring the wavelength and/or power of the light emitted by the light emitter; and
a light coupling sub-module comprising:
a submount comprising a silicon substrate, the submount being in mechanical communication with an optical fiber receptacle;
a lens holder attached to the submount, the lens holder having a mounting surface; and
a microlens comprising:
a mounting surface; and
a curved section having an optical axis;
wherein the microlens mounting surface is attached to the lens holder mounting surface and the optical axis is aligned with the optical fiber receptacle such that, when an optical fiber is connected to the optical fiber receptacle, an optical signal can be effectively created by the light emitter, received by the microlens, and coupled into the optical fiber.
2. An optical micro-module as defined in claim 1 , wherein the back monitor comprises:
a reflective surface that receives light from a back facet of the light emitter and redirects the light;
a first lens that receives a first portion of the redirected laser light reflected by the reflective surface, wherein the first lens collimates the laser light;
a second lens that receives a second portion of the redirected laser light reflected by the reflective surface, wherein the second lens collimates the laser light;
a filter layer that receives the collimated light from at least one of the first lens and the second lens; and
a detector selected from the group consisting of a power sensor and a wavelength sensor, wherein the detector receives light through the filter to detect a signal and wherein at least one of the light power or light wavelength is determined from the signal.
3. An optical micro-module as defined in claim 1 , further comprising a micro isolator attached to the submount to prevent backreflections from interfering with the operation of the light emitter.
4. An optical micro-module as defined in claim 1 , wherein the microlens mounting surface has a metal coating thereupon and the metal coating is soldered to the lens holder mounting surface, thereby affixing the microlens to the lens holder.
5. An optical micro-module as defined in claim 1 , wherein the microlens comprises an aspheric silicon microlens.
6. An optical micro-module as defined in claim 1 , wherein:
the submount has a silicon v-groove thereon; and
the optical fiber is attached to the silicon v-groove.